Bilateral subthalamic deep brain stimulation using single track microelectrode recording

Background  

Microelectrode recording (MER) is widely used during deep brain stimulation (DBS) procedures because MER can identify structural borders and eloquent structures, localize somatotopic arrangements, and provide an outline of the three-dimensional shapes of target nuclei. However, MER may cause intracranial hemorrhage. We preformed single track MER during DBS procedures, analyzed the accuracy of electrode positioning with MRI, and compared the amount of air and the potential risk of intracranial hemorrhage.     

A sine-wave-shaped skin incision for inserting deep-brain stimulators

Background

The sine-wave-shaped skin incision is a technique that minimizes skin-related complications near burr hole caps after electrode placement for deep-brain stimulation (DBS).

Methods

Between 2011 and 2013, 54 DBS electrodes were implanted in 27 consecutive patients with Parkinson’s disease (PD), essential tremor, or dystonia. The sine-wave incision was used in 26 patients and conventional bilateral linear scalp incisions were used in one patient.

Results

None of the patients whose operations involved sine-wave-shaped incisions developed hardware-linked complications such as skin infection or skin erosion. The one patient who underwent conventional bilateral linear scalp incisions developed a skin infection.

Conclusion

By preserving the vascular anatomy of the scalp and reducing skin tension at the wound site, the sine-wave-shaped incision promotes wound healing.     

Accuracy of stimulating electrode placement in paediatric pallidal deep brain stimulation for primary and secondary dystonia

Background

Accuracy of electrode placement is an important determinant of outcome following deep brain stimulation (DBS) surgery. Data on accuracy of electrode placement into the globus pallidum interna (GPi) in paediatric patients is limited, particularly those with non-primary dystonia who often have smaller GPi. Pallidal DBS is known to be more effective in the treatment of primary dystonia compared with secondary dystonia.

Objectives

We aimed to determine if accuracy of pallidal electrode placement differed between primary, secondary and NBIA (neuronal degeneration and brain iron accumulation) associated dystonia and how this related to motor outcome following surgery.

Methods

A retrospective review of a consecutive cohort of children and young people undergoing DBS surgery in a single centre. Fused in frame preoperative planning magnetic resonance imaging (MRI) and postoperative computed tomography (CT) brain scans were used to determine the accuracy of placement of DBS electrode tip in Leskell stereotactic system compared with the planned target. The differences along X, Y, and Z coordinates were calculated, as was the Euclidean distance of electrode tip from the target. The relationship between proximity to target and change in Burke-Fahn-Marsden Dystonia Rating Scale at 1 year was also measured.

Results

Data were collected from 88 electrodes placed in 42 patients (14 primary dystonia, 18 secondary dystonia and 10 NBIA associated dystonia). Median differences between planned target and actual position were: left-side X-axis 1.05 mm, Y-axis 0.85 mm, Z-axis 0.94 mm and Euclidean difference 2.04 mm; right-side X-axis 1.28 mm, Y-axis 0.70 mm, Z-axis 0.70 mm and Euclidean difference 2.45 mm. Accuracy did not differ between left and right-sided electrodes. No difference in accuracy was seen between primary, secondary or NBIA associated dystonia. Dystonia reduction at 1 year post surgery did not appear to relate to proximity of implanted electrode to surgical target across the cohort.

Conclusions

Accuracy of surgical placement did not differ between primary, secondary or NBIA associated dystonia. Decreased efficacy of pallidal DBS in secondary and NBIA associated dystonia is unlikely to be related to difficulties in achieving the planned electrode placement.     

Frameless image-guided stereotaxy with real-time visual feedback for brain biopsy

Background

Frame-based stereotaxy remains the “gold standard” for cerebral biopsies and functional neurosurgery though new frameless stereotactic systems are evolving continually. As the technique of frameless stereotaxy gains increasing acceptance among neurosurgeons, this study assesses the feasibility of a system for frameless image-guided stereotaxy.

Methods

All patients biopsied for intracranial lesions between February 2007 and August 2010 using the BrainLAB VarioGuide frameless stereotactic system were evaluated prospectively. Prior to surgery, patients underwent magnetic resonance (MR) imaging; additionally, fluoroethyl-tyrosine (FET)-positron emission tomography (PET) images were acquired and fused to MR images in selected cases. Biopsy trajectory length, lesion volume, procedure duration, and diagnostic yield were assessed.

Results

Ninety-six diagnostic biopsies in 91 patients were evaluated. Lesion volume ranged from 0.17 to 121.8?cm³; trajectory length from 25.3 to 101.9?mm. Diagnostic yield was 93.8%. Mean operation time from skin incision to wound closure was 42?min; in the operating room, it was 99?min.

Conclusions

Clinical experience indicates VarioGuide to be safe and accurate. Reachable range of lesion localisation appears to be comparable to a frame-based stereotaxy system. Operation times are brief. The unique design of this frameless stereotactic system allows real-time visual feedback of needle positioning.     

A step-wise approach to deep brain stimulation in mice

Background

Studies of deep brain stimulation (DBS) in mice are rare due to their small size, agility, aversion to handling, and high anxiety compared to larger species. Studying DBS modulation of neural circuitry in murine models of human behavior may ensure safety, guide stimulatory parameters for clinical trials in humans, and inform a long-eluded mechanism.

Methods

Stereotactic deep brain electrode implantation in a mouse is performed. Mechanical etching of the skull with a high-speed drill is used with placement of cyanoacrylate glue and molding of dental acrylate to affix the electrode in place. Stimulation experiments are conducted in the home cage after a habituation period. After testing is complete, electrode placement is verified in fixed tissue.

Results

Electrodes can be safely and accurately implanted in mice for DBS experimentation. Previous findings demonstrated accuracy in placement within the nucleus accumbens shell of 93 % [14]. In this study, there were no hardware malfunctions that required interrupting experimentation.

Conclusions

Stereotactic DBS studies may be safely and effectively performed in mice to investigate neuropsychiatric disorders. In addition, examining the biochemical and molecular mechanisms underlying these disorders may be facilitated by widely available transgenic mouse lines and the Cre-Lox recombination system.     

The efficacy and safety of chitosan dextran gel in a burr hole neurosurgical sheep model

Background

Achieving and maintaining haemostasis is of paramount importance in neurosurgery. Chitosan has been shown in both animal and human models to be significantly effective in haemostasis as well as in reducing adhesion formation.

Objectives

To evaluate the haemostatic potential and to study histopathological changes caused by novel chitosan dextran gel in a neurosurgical sheep model.

Method

Ten sheep underwent neurosurgical burr hole procedure. Bleeding control was tested at the level of bone, dura and brain separately with both chitosan gel and Gelfoam paste on separate burr holes. Baseline bleeding was measured at the time of injury using the Boezaart scale, and then every 2 min after the application of each agent until complete haemostasis or 10 min, whichever was earlier. Safety was assessed through MRI scans and histopathological analysis.

Results

Mixed modeling showed no statistical difference in time to haemostasis between chitosan gel and Gelfoam paste (means of log-normalized areas under the curve were 1.3688 and 1.3196 respectively) for each burr hole (p?=?0.7768). Logistic regression modeling showed that Chitosan significantly decreased the incidence of bleeding beyond the first time point measured after application of the treatment when compared to Gelfoam (OR?=?2.7, p?=?0.04). Average edema volume (cm³) on post-operative MRI was 0.97 for Gelfoam and 1.11 for (p?=?0.49) while average histology scores were 2.5 for Gelfoam versus 3.3 for chitosan (p?=?0.32).

Conclusion

Chitosan dextran gel is an effective haemostatic agent to control bleeding in brain tissue. It is safe and nontoxic to neural tissue.     

Analysis of hemorrhagic risk factors during deep brain stimulation surgery for movement disorders: comparison of the circumferential paired and multiple electrode insertion methods

Background  

The most serious complication of deep brain stimulation (DBS) surgery is intracranial hemorrhage. The authors have assessed risk factors for hemorrhage in DBS surgery and compared two types of microelectrode insertion technique on hemorrhagic risk.     

Expanding applications of deep brain stimulation: a potential therapeutic role in obesity and addiction management

Background

The indications for deep brain stimulation (DBS) are expanding, and the feasibility and efficacy of this surgical procedure in various neurologic and neuropsychiatric disorders continue to be tested. This review attempts to provide background and rationale for applying this therapeutic option to obesity and addiction. We review neural targets currently under clinical investigation for DBS??the hypothalamus and nucleus accumbens??in conditions such as cluster headache and obsessive-compulsive disorder. These brain regions have also been strongly implicated in obesity and addiction. These disorders are frequently refractory, with very high rates of weight regain or relapse, respectively, despite the best available treatments.

Methods

We performed a structured literature review of the animal studies of DBS, which revealed attenuation of food intake, increased metabolism, or decreased drug seeking. We also review the available radiologic evidence in humans, implicating the hypothalamus and nucleus in obesity and addiction.

Results

The available evidence of the promise of DBS in these conditions combined with significant medical need, support pursuing pilot studies and clinical trials of DBS in order to decrease the risk of dietary and drug relapse.

Conclusions

Well-designed pilot studies and clinical trials enrolling carefully selected patients with obesity or addiction should be initiated.     

Robotic implantation of deep brain stimulation leads, assisted by intra-operative, flat-panel CT

Background

There are two mandatory skills in deep brain stimulation (DBS) neurosurgery: accuracy and control.

Method

Frame-based robotic registration was performed. Prior to insertion into the skull, the guide tube’s position was checked with flat-panel computed tomography (fpCT). After registration against the pre-operative plan, we measured and corrected the robotic arm’s position so that the guide tube with the micro-electrode would follow the planned trajectory exactly. We then used fpCT again to check the DBS lead’s final position.

Conclusion

The combination of intra-operative fpCT with robotised surgery provides an appropriate, user-friendly solution to the key technical challenges in DBS lead implantation.     

Five-Year Changes in Psychiatric Treatment Status and Weight-Related Comorbidities Following Bariatric Surgery in a Veteran Population

Background

Although bariatric surgery is an established treatment for obesity, less is known regarding the long-term effects of surgery on psychiatric function. This paper reports changes in psychiatric treatment status, weight, and weight-related comorbidities over 5?years of follow-up among a population of veterans completing bariatric surgery.

Methods

We assessed 55 veterans undergoing bariatric surgery at a single Veteran Affairs medical center for 5?years post-surgery. Patients completed a pre-surgery clinical interview with a licensed psychologist. Using computerized medical records, we tracked pre- to post-surgery involvement with antidepressants, anxiolytics, psychotherapies, and overall psychiatric treatment visits along with changes in weight and metabolic function.

Results

Rates of antidepressant use and/or involvement with psychotherapy for depression declined from 56.4?% at pre-surgery to 34.6?% at 5?years post-surgery, p?=?0.01. Anxiolytic use and/or involvement with psychotherapy for anxiety, however, increased from 23.6 to 32.7?% pre- to 5?years post-surgery. Average psychiatric treatment volume remained similar to pre-surgery status across follow-up. These mixed indicators of psychiatric improvement occurred despite marked metabolic improvements from surgery. Mean percent excess weight loss?=?51.7 and 41.3 (1 and 5?years post-surgery, respectively), systolic blood pressure (?6.8?mmHg (14.3)/?6.1?mmHg (12.8), respectively), glucose levels (?18.6?mg/dL (30.2)/?10.0?mg/dL (25.9), respectively), triglycerides (?78.2?mg/dL (96.7)/?69.1?mg/dL (102.2), respectively) and high-density lipoproteins (+7.1 (9.9)/+11.3 (11.3), respectively) levels each improved.

Conclusions

We report evidence of decreased antidepressant use and depression therapies following bariatric surgery, but no improvements on rates of anxiolytic use and anxiety therapies or on overall psychiatric treatment involvement. Despite metabolic improvements, bariatric patients with psychiatric histories may warrant ongoing attention to mental health.     

Changes in Bone Mineral Density in Women Following 1-Year Gastric Bypass Surgery

Background

Roux-en-Y gastric bypass (RYGB) surgery is the gold standard surgical treatment for obesity. However, unintended nutritional deficiencies following this surgery are common, including changes in bone metabolism. We assessed changes in bone mineral density (BMD), nutritional compounds, and bone resorption markers before and 1?year following RYGB surgery.

Methods

Our study included 22 female patients with class II/III obesity. A clinical questionnaire, a 24-h recall, blood and urine samples, and dual-energy X-ray absorptiometry were provided.

Results

Mean age was 37.2?±?9.6?years; 86?% were Caucasian and 77.2?% were premenopausal. Mean preoperative body mass index was 44.4?±?5.0 and 27.5?±?4.5?kg/m² at 1-year follow-up (p?p?=?0.327]. Serum N-telopeptide (16.3?±?3.4 vs. 38.2?±?7.0 nM BCE, p?p?=?0.026) increased after RYGB surgery, reflecting bone resorption. BMD decreased after RYGB surgery in the lumbar spine (1.13?±?0.11 vs. 1.04?±?0.09?g/cm², p?=?0.001), femoral neck (1.03?±?0.15 vs. 0.94?±?0.16?g/cm², p?=?0.001), and total femur (1.07?±?0.11 vs. 0.97?±?0.15?g/cm², p?=?0.003).

Conclusions

Decreased BMD in the lumbar spine, femoral neck, and total femur is detectable in women 1?year after RYGB surgery. Calcium malabsorption, caused by vitamin D deficiency and increased bone resorption, is partially responsible for these outcomes and should be targeted in future clinical trials.     

One-step tunneling of DBS extensions—a technical note

Background

Infection constitutes a serious adverse event in deep brain stimulation (DBS) surgery, being responsible for difficult therapeutic decisions that may ultimately involve the removal of implanted material. Some cases begin with skin erosion and wound dehiscence of the retroauricular incision, which is one of the most fragile points. Several techniques of rotation flaps and skin reconstruction, as well as prolonged antibiotic regimens, have been proposed as therapeutic options. To prevent the onset of this complication, the authors propose a one-step tunneling technique of DBS extensions, avoiding the opening of the retroauricular space.

Methods

We describe a surgical technique of a one-step tunneling of DBS extensions in 20 patients submitted to subthalamic DBS for Parkinson’s disease, avoiding the opening of the retroauricular space.

Results

After implantation of the extensions using this technique, we had no erosions of the retroauricular skin, with a consequent reduction in the number of infections.

Conclusions

The authors describe an easy surgical technique that allows reduction of wound and erosion complications, with great benefits for DBS patients.     

Low-grade CSF leaks in endoscopic trans-sphenoidal pituitary surgery: efficacy of a simple and fully synthetic repair with a hydrogel sealant

Background

Intra-operative CSF leak during endoscopic trans-sphenoidal surgery is not uncommon. Surgical repair with a variety of autologous grafts, rigid buttresses and CSF diversion techniques that add time and complexity have been reported.

Objective

To describe a simple and purely synthetic closure for low-grade CSF leaks following endoscopic trans-sphenoidal pituitary surgery.

Methods

A retrospective review of all endoscopic trans-sphenoidal surgery undertaken for pituitary pathology between 2005 and 2010 was carried out. The grade of CSF leak and success of graded repair was noted. Patients with no CSF leak (grade 0) had gelatin sponge placed in the tumour cavity. In those with low-grade CSF leak through small arachnoid defects (grade 1), repair was carried out using gelatin sponge and hydrogel sealant overlay. CSF diversion was not employed for low-grade CSF leaks.

Results

Of the 255 endoscopic trans-sphenoidal surgeries, 158 (62%) had no leak (grade 0) and 74 (29%) had a low-grade leak (grade 1). Repairs in all cases were of grade 0, and all but two cases of grade 1 CSF leak were successful at a mean follow-up of 29?months. The 2 (2.7%) post-operative CSF leaks were seen within 6?weeks of surgery. Both cases were related to bouts of sneezing and were repaired using further trans-sphenoidal surgery and/or lumbar CSF diversion.

Conclusions

A simple purely synthetic repair of low-grade CSF leaks is described. This repair is safe and comparable in efficacy whilst avoiding the morbidity related to more complex sellar reconstructions previously described.     

Axis I Disorders in Adjustable Gastric Band Patients: the Relationship Between Psychopathology and Weight Loss

Background

Bariatric surgery candidates have higher rates of co-morbid psychological illnesses than those in the general population. The effect of weight loss on these illnesses is unclear.

Methods

This prospective observational study explored psychiatric co-morbidities and weight loss outcomes in 204 gastric banding surgery candidates. Psychiatric co-morbidities were assessed prior to surgery and 2 years post-surgery. One hundred and fifty patients (74 %) completed assessments at both time points.

Results

At baseline, 39.7 % of the patients met the criteria for a current axis I disorder as defined by the Diagnostic and Statistical Manual of Mental Disorders, 4th Edition (DSM-IV). Mood disorders were the most frequent (26.5 %), followed by anxiety disorders (15.2 %) and binge eating disorder (13.2 %). Preoperative psychopathology predicted clinical psychopathology at 2 years. No preoperative or post-operative axis I disorder was significantly related to weight loss at 2 years. The frequency of current axis I disorders decreased significantly from 39.7 % preoperatively to 20 % 2 years post-surgery.

Conclusions

The point prevalence of psychopathology in this sample of Australian bariatric candidates is high. Psychopathology, preoperatively and at 2 years of follow-up, was not associated with weight loss at 2 years.     

Changes in Metabolic Profile and Adipoinsular Axis in Morbidly Obese Premenopausal Females Treated with Restrictive Bariatric Surgery

Background

The aim of the present study was to evaluate the effects of surgically induced weight loss on the metabolic profile and adipocytokine levels in premenopausal morbidly obese females.

Methods

Twenty premenopausal morbidly obese (MO) women with a median age of 34?years (range: 24?C48?years) and a median body mass index (BMI) of 41.47?kg/m² (range: 38.0?C56.73?kg/m²) were studied (13 women underwent gastric banding and 7 women underwent sleeve gastrectomy). In addition, 20 lean premenopausal women with a median age of 32?years (range: 22?C44?years) and a median BMI of 20.0?kg/m² (range: 18.5?C24.7?kg/m²) were also studied. Anthropometric measurements and metabolic parameters were analyzed in each patient, along with changes in leptin, adiponectin, resistin, and interleukin-6 (IL-6) before surgery, 6?months after surgery, and 12?months after surgery. Comparisons with the reference normal-weight subjects were also performed.

Results

Both weight and BMI were found to be significantly decreased postoperatively. A 54.5% loss of excess BMI was observed 12?months after surgery, and was associated with significant improvement in all anthropometric and metabolic parameters. Twelve months after surgery we also observed decreased levels of serum leptin, resistin, and IL-6; increased levels of serum adiponectin; and a remarkable improvement in metabolic syndrome markers. Furthermore, postoperative serum resistin and IL-6 levels were found to reach those of normal-weight volunteers.

Conclusions

The results of this study suggest that weight loss through restrictive bariatric surgery results in a significant reduction in leptin, resistin, and IL-6 levels, and an increase in adiponectin levels, in addition to improving insulin sensitivity and glucose and lipid homeostasis in young morbidly obese female patients. These changes were significantly correlated with the magnitude of weight loss.     

Head positioning and risk of pneumocephalus, air embolism, and hemorrhage during subthalamic deep brain stimulation surgery

Purpose  

The objective of the present study was to evaluate the risk of pneumocephalus, venous air embolism (VAE), and intracranial hemorrhage in subthalamic nucleus (STN) deep brain stimulation (DBS) patients operated in the strict supine (head and body flat) position.     

Acute brain reaction to DBS electrodes after deep brain stimulation: chronological observation

Background

As increasing numbers of deep brain stimulation (DBS) procedures are performed, rare abnormal findings on postoperative images that are not attributable to well-known complications are reported. Between 2005 and 2012, we encountered several symptomatic patients with transient abnormal low-attenuation lesions on postoperative computed tomography (CT) scans. The aim of this study was to clarify this rare phenomenon using chronological observations and to suggest a feasible mechanism.

Results

In this period, seven (3.2 %) patients displayed transient increased low-attenuation signals, circumferentially surrounding the DBS electrodes and extending into the subcortical white matter. All these patients suffered from unexpected but transient neurological symptoms during the postoperative period. The abnormal low-attenuation lesions only disappeared completely a considerable time after the clinical symptoms had disappeared, without treatment in most patients.

Conclusions

We report here our chronological observations of acute brain reactions after DBS procedures, which we believe are neither infectious nor vascular, but are possibly caused by the mechanical breakdown of the blood–brain barrier by microelectrode recordings or by anchored DBS electrodes. These lesions are thought to constitute a self-limiting disorder requiring no further treatment.     

Intracranial hypotension with a sixth cranial nerve palsy subsequent to massive thoracic CSF hygroma: a rare complication of thoracic disc excision

Background

Thoracic cerebrospinal fluid (CSF) hygroma is a rare and potentially devastating complication of the anterior thoracic approach to the spine. We present two cases in which this complication resulted in acute cranial nerve palsy and discuss the pathoanatomy and management options in this scenario.

Case reports

Two male patients presented to our department with neurological deterioration due to a giant herniated thoracic disc. The extruded disc fragment was noted pre-operatively to be calcified in both patients. A durotomy was performed at primary disc prolapse resection in the first patient, whereas an incidental durotomy during the procedure caused complication in the second patient. These were repaired primarily or sealed with Tachosil^®. Both patients re-presented with acute diplopia. Imaging of both patients confirmed a massive thoracic cerebrospinal fluid hygroma and evidence of intracranial changes in keeping with intracranial hypotension, but no obvious brain stem shift. The hemithorax was re-explored and the dural repair was revised. The first patient made a full recovery within 3 months. The second patient was managed conservatively and took 5 months for improvement in his ophthalmic symptoms.

Conclusions

The risk of CSF leakage post-dural repair into the thoracic cavity is raised due to local factors related to the chest cavity. Dural repairs can fail in the presence of an acute increase in CSF pressure, for example whilst sneezing. Intracranial hypotension can result in subsequent hygroma and possibly haematoma formation. The resultant cranial nerve palsy may be managed expectantly except in the setting of symptomatic subdural haematoma or compressive pneumocephaly.     

Intracranial hemorrhage following lumbar spine surgery

Background

Intracranial hemorrhage is a serious but rare complication of spinal surgery, which can occur in the intracerebral, cerebellar, epidural, or subdural compartment.

Purpose

To describe patients with intracranial hemorrhage after lumbar spinal surgery and present clinical and diagnostic imaging findings.

Methods

In this retrospective study, medical records of 1,077 patients who underwent lumbar spinal surgery in our tertiary referral neurosurgery center between January 2003 and September 2010 were studied. The original presentations of the patients before the surgical intervention were herniated lumbar disc, spinal canal stenosis, spondylolisthesis, lumbar spinal trauma, and lumbar spine and epidural tumor. The operations performed consisted of discectomy, multiple level laminectomy, stabilization and fusion, lumbar instrumentation, and lumbar spinal and epidural tumor resection.

Results

Four cases developed intracranial hemorrhage including acute subdural hematoma (one case), epidural hematoma (one case), and remote cerebellar hemorrhage (two cases). The clinical and diagnostic imaging characteristics along with treatments performed and outcomes of these four patients are described and the pertinent literature regarding post-lumbar spinal surgery intracranial hemorrhages is reviewed.

Conclusion

Though rare, intracranial hemorrhage can occur following lumbar spinal surgery. This complication may be asymptomatic or manifest with intense headache at early stages any time during the first week after surgery. Dural tear, bloody CSF leakage, focal neurologic symptoms, and headache are indicators of potential intracranial hemorrhage, which should be considered during or following surgery and necessitate diagnostic imaging.