Use of monopolar cautery in patient with a vagal nerve stimulator during neuromuscular scoliosis surgery.

It is a historic and common practice while performing spine surgery on patients with a VNS has been to have the patient's neurologist turn off the VNS generator in the pre-operative anesthetic care unit and to use bipolar rather than monopolar electrocautery. Here we report a case of a 16-year-old male patient with cerebral palsy and refractory epilepsy managed with an implanted VNS who had scoliosis surgery (and subsequent hip surgery) conducted with the use of monopolar cautery. Although VNS manufacturer guidelines suggest that monopolar cautery should be avoided, perioperative care providers should consider its selective use in high-risk instances (with greater risks of morbidity and mortality due to blood loss which outweigh the risk of surgical re-insertion of a VNS) such as cardiac or major orthopedic surgery. Considering the number of patients with VNS devices presenting for major orthopedic surgery is increasing, it is important to have an approach and strategy for perioperative management of VNS devices.

Longitudinal Assessment of Enhancing Foci of Abnormal Signal Intensity in Neurofibromatosis Type 1.

BACKGROUND AND PURPOSE: Patients with neurofibromatosis 1 are at increased risk of developing brain tumors, and differentiation from contrast-enhancing foci of abnormal signal intensity can be challenging. We aimed to longitudinally characterize rare, enhancing foci of abnormal signal intensity based on location and demographics. MATERIALS AND METHODS: A total of 109 MR imaging datasets from 19 consecutive patients (7 male; mean age, 8.6 years; range, 2.3-16.8 years) with neurofibromatosis 1 and a total of 23 contrast-enhancing parenchymal lesions initially classified as foci of abnormal signal intensity were included. The mean follow-up period was 6.5 years (range, 1-13.8 years). Enhancing foci of abnormal signal intensity were followed up with respect to presence, location, and volume. Linear regression analysis was performed. RESULTS: Location, mean peak volume, and decrease in enhancing volume over time of the 23 lesions were as follows: 10 splenium of the corpus callosum (295 mm3, 5 decreasing, 3 completely resolving, 2 surgical intervention for change in imaging appearance later confirmed to be gangliocytoma and astrocytoma WHO II), 1 body of the corpus callosum (44 mm3, decreasing), 2 frontal lobe white matter (32 mm3, 1 completely resolving), 3 globus pallidus (50 mm3, all completely resolving), 6 cerebellum (206 mm3, 3 decreasing, 1 completely resolving), and 1 midbrain (34 mm3). On average, splenium lesions began to decrease in size at 12.2 years, posterior fossa lesions at 17.1 years, and other locations at 9.4 years of age. CONCLUSIONS: Albeit very rare, contrast-enhancing lesions in patients with neurofibromatosis 1 may regress over time. Follow-up MR imaging aids in ascertaining regression. The development of atypical features should prompt further evaluation for underlying tumors.

Gauging the effectiveness of canal occlusion surgery: how I do it.

BACKGROUND: Transmastoid occlusion of the posterior or superior semicircular canal is an effective and safe management option in patients with refractory benign paroxysmal positional vertigo or symptomatic superior semicircular canal dehiscence. A method of quantifying successful canal occlusion surgery is described. METHODS: This paper presents representative patients with intractable benign paroxysmal positional vertigo or symptomatic superior semicircular canal dehiscence, who underwent transmastoid occlusion of the posterior or superior semicircular canal respectively. Vestibular function was assessed pre- and post-operatively. The video head impulse test was included as a measure of semicircular canal and vestibulo-ocular reflex functions. RESULTS: Post-operative video head impulse testing showed reduced vestibulo-ocular reflex gain in occluded canals. Gain remained normal in the non-operated canals. Post-operative audiometry demonstrated no change in hearing in the benign paroxysmal positional vertigo patient and slight hearing improvement in the superior semicircular canal dehiscence syndrome patient. CONCLUSION: Transmastoid occlusion of the posterior or superior semicircular canal is effective and safe for treating troublesome benign paroxysmal positional vertigo or symptomatic superior semicircular canal dehiscence. Post-operative video head impulse testing demonstrating a reduction in vestibulo-ocular reflex gain can reliably confirm successful occlusion of the canal and is a useful adjunct in post-operative evaluation.

MRI, Magnetoencephalography, and Surgical Outcome of Oligodendrocytosis versus Focal Cortical Dysplasia Type I.

BACKGROUND AND PURPOSE: Abnormalities of oligodendrocytes have been reported in surgical specimens of patients with medically intractable epilepsy. The aim of this study was to compare the MR imaging, magnetoencephalography, and surgical outcome of children with oligodendrocytosis relative to focal cortical dysplasia I. MATERIALS AND METHODS: Oligodendrocytosis included oligodendroglial hyperplasia, oligodendrogliosis, and oligodendroglial-like cells in the white matter, gray matter, or both from children with medically intractable epilepsy. Focal cortical dysplasia I included radial and tangential cortical dyslamination. The MR imaging, magnetoencephalography, type of operation, location, and seizure outcome of oligodendrocytosis, focal cortical dysplasia I, and oligodendrocytosis + focal cortical dysplasia I were compared. RESULTS: Eighteen subjects (39.1%) had oligodendrocytosis, 21 (45.7%) had focal cortical dysplasia I, and 7 (15.2%) had oligodendrocytosis + focal cortical dysplasia I. There were no significant differences in the type of seizures, focal or nonfocal epileptiform discharges, magnetoencephalography, and MR imaging features, including high T1 signal in the cortex, high T2/FLAIR signal in the cortex or subcortical white matter, increased cortical thickness, blurring of the gray-white junction, or abnormal sulcation and gyration among those with oligodendrocytosis, focal cortical dysplasia I, or oligodendrocytosis + focal cortical dysplasia I (P > .01). There were no significant differences in the extent of resection (unilobar versus multilobar versus hemispherectomy), location of the operation (temporal versus extratemporal versus both), or seizure-free outcome of oligodendrocytosis, focal cortical dysplasia I, and oligodendrocytosis + focal cortical dysplasia I (P > .05). CONCLUSIONS: Oligodendrocytosis shared MR imaging and magnetoencephalography features with focal cortical dysplasia I, and multilobar resection was frequently required to achieve seizure freedom. In 15% of cases, concurrent oligodendrocytosis and focal cortical dysplasia I were identified. The findings suggest that oligodendrocytosis may represent a mild spectrum of malformations of cortical development.

Clipping of sigmoid sinus diverticulum: how I do it.

OBJECTIVE: To report two cases of transmastoid clipping of a sigmoid sinus diverticulum. METHODS: Two patients with pulsatile tinnitus resulting from a sigmoid sinus diverticulum underwent clipping at the diverticulum neck using intra-operative Doppler ultrasonography. RESULTS: At six months' follow up, both patients reported complete resolution of pulsatile tinnitus with no complications. CONCLUSION: Transmastoid clipping of a sigmoid sinus diverticulum can be a safe and effective method of managing pulsatile tinnitus resulting from a sigmoid sinus diverticulum.

Internal carotid artery aneurysm in skull base osteomyelitis: does the pattern of cranial nerve involvement matter?

OBJECTIVE: Carotid artery aneurysm is a potentially fatal complication of skull base osteomyelitis. It is important to know the warning signs for this complication, as early diagnosis is of great importance. This report aimed to determine whether the pattern of cranial nerve involvement may predict the occurrence of aneurysm involving the internal carotid artery in skull base osteomyelitis. METHODS: Two diabetic patients with skull base osteomyelitis were incidentally diagnosed with pseudo-aneurysm of the petrous internal carotid artery on follow-up magnetic resonance imaging. They presented with lower cranial nerve palsy; however, facial nerve function was almost preserved in both cases. Computed tomography angiography confirmed aneurysms at the junction of the horizontal and vertical segments of the petrous carotid artery. RESULTS: Internal carotid artery trapping was conducted using coil embolisation. Post-coiling magnetic resonance imaging demonstrated no procedure-related complications. Regular follow up has demonstrated that patients' symptoms are improving. CONCLUSION: One should be mindful of this potentially fatal complication in skull base osteomyelitis patients with lower cranial nerve palsies, with or without facial nerve involvement, especially in the presence of intracranial thromboembolic events or Horner's syndrome.

The behaviour of residual tumour after the intentional incomplete excision of a vestibular schwannoma: is it such a bad thing to leave some behind?

OBJECTIVES: To evaluate the biological behaviour of tumour remnants intentionally left in the surgical bed following the incomplete excision of vestibular schwannomas (VS) and to review the relation between extent of resection and preservation of facial nerve function. METHODS: A retrospective chart review of 450 patients who underwent surgery for resection of VS over 23 years (1992-2014). Of these, 50 (11%) patients had residual tumour intentionally left on/around the facial nerve (near-total or subtotal excision) to preserve facial nerve function intra-operatively. The growth of residual tumour was evaluated using serial magnetic resonance imaging scanning; pre- and postoperative facial nerve function was assessed using the House-Brackmann grading scale. SETTING: Tertiary referral neurotology unit. RESULTS: Of the 42 non-NF2 cases where the tumour was intentionally incompletely excised, 28 (67%) patients underwent subtotal resection (mean follow-up 68.5 ± 39.0 months) and 14 (33%) underwent near-total resection (mean follow-up 72.9 ± 48.3 months). Three patients (all in subtotal resection group) showed regrowth. This was not statistically different from the near-total resection group (χ2 = 0.92, P = 0.31). The mean overall growth for these cases was 0.68 mm ± 0.32 mm/year. 5 (one near total, four subtotal) of the eight NF2 patients (62.5%) were excluded from our analysis. In the non-NF2 group, poor facial nerve outcomes (House-Brackmann scores of III-IV) were seen in 2/14 and V-VI in 3/14 of the near total compared with 7/25 and 4/25 respectively in the subtotal group. CONCLUSIONS: Given that the primary surgery for the VS was only for tumours that were relatively large or grew during conservative treatment, the low rate of tumour remnant growth (7%) is reassuring. It may be appropriate to have a lower threshold for leaving tumour on the facial nerve in non-NF2 patients where complete resection may jeopardise facial nerve function.

Olfactory and cochleovestibular dysfunction after head injury in the workplace: an updated series.

OBJECTIVES: The objective of this study was to determine the incidence of olfactory dysfunction in workers following head injury in the work place, to define its relationship to the site, severity of injury and direction of force. The demographics of head injured workers were also assessed to determine whether those with olfactory loss were more likely to have sustained a cochleovestibular injury. DESIGN: Retrospective case analysis. SETTING: Tertiary referral university hospital in Toronto, Ontario. PARTICIPANTS: A total of 3438 consecutive patients referred from the Workplace Safety and Insurance Board (WSIB) in the province of Ontario who sustained a work-related head injury were assessed between 1987 and 2014. MAIN OUTCOME MEASURES: Olfactory and cochleovestibular dysfunction assessed by history, clinical examination and subjective and objective tests. RESULTS: Olfactory dysfunction (OD) was identified in 413 of 3438 patients (12.0%) of which 321 were diagnosed with anosmia and 92 with hyposmia. In our series, injuries from a fall were the commonest cause for OD and a frontal or mid-face impact was more likely to result in OD than other regions (P = 0.0002). A loss of consciousness (LOC) of any duration correlated with OD. In those with olfactory dysfunction, an associated skull fracture occurred in 37.1% of patients and a CSF leak in 4.1%, which was significantly higher compared with those without OD(<0.0001). Patients with OD had a higher incidence of cochlear and vestibular loss (19.9% and 20.6%, respectively) compared with those without OD (14.3% and 17.1%, respectively). CONCLUSIONS: Post-traumatic olfactory dysfunction is more likely to occur in patients who experienced a moderate to severe head injury, LOC and more likely to result from a frontal or mid-face blow to the skull. Cochleovestibular dysfunction is likely to occur concurrently with olfactory dysfunction.

Intratympanic therapy in Meniere's syndrome or disease: up to date evidence for clinical practice.

BACKGROUND: Meniere's syndrome or disease (MS/D) is typically characterised by episodic vertigo, aural fullness, tinnitus and fluctuating hearing loss. There are multiple options available for treatment with variation in consensus on the best intervention. OBJECTIVE: To evaluate the evidence on the efficacy of intratympanic therapies [steroids, gentamicin, antivirals and other therapies] on the frequency and severity of vertigo and other symptoms of MS/D. SEARCH STRATEGY: A literature search was performed on AMED, EMBASE, HMIC, MEDLINE, PsycINFO, BNI, CINAHL, HEALTH BUSINESS ELITE, CENTRAL and Cochrane Ear, Nose and Throat disorders group trials register using various MeSH. The search was restricted to English and human subjects, and the last date of search was December 2014. SELECTION CRITERIA: Randomised controlled trials of intratympanic therapies [steroids, gentamicin antivirals and latanoprost] versus a placebo or another treatment. RESULTS: We analysed 8 RCT's comparing intratympanic steroids, gentamicin, ganciclovir (antiviral) and latanoprost versus another form of intratympanic treatment or placebo. CONCLUSIONS: On the basis of 6 RCT's (n = 242), there is evidence to support the effectiveness of intratympanic steroids and gentamicin to control symptoms of vertigo in MS/D albeit with a risk of hearing loss with gentamicin. However, there was no consensus found on doses or treatment protocols. There was no evidence to support the use of other forms of intratympanic therapy (antivirals and latanoprost) in MS/D.

Epilepsy surgery: recent advances in brain mapping, neuroimaging and surgical procedures.

The general principle of epilepsy surgery is to achieve seizure freedom without causing any neurological deficit that would outweigh the clinical benefit. To achieve this, the epileptogenic zone, which is the part of the brain responsible for seizure generation, as well as the anatomic location of the eloquent cortex must be precisely identified in order to spare those functions during excision of the epileptogenic tissue. Major technical advances over the last decade have continuously contributed to increase our ability to map the brain and identify these critical areas. These technologies and innovations that can be routinely used today include non-invasive studies such as magnetoencephalography (MEG), functional MRI (fMRI), simultaneous EEG-fMRI, and nuclear medicine based methods like PET and SPECT as well as invasive studies through chronically implanted electrodes. Electrodes can be either placed subdurally via burr holes and craniotomies or within the brain parenchima via frame-based and frameless stereotactic methods. Apart from a continuous change in these insertion techniques, the most valuable advances here include recordings on high frequency bandwidth (100-600 Hz EEG) that are capable to delineate high-frequency oscillations (HFOs). These HFOs have been recognized as a biomarker for epileptogenic tissue. All of these technical advances have made epilepsy surgery a truly multidisciplinary field and surgeons have to be able to understand and interpret all of the gathered data. Moreover, this development has influenced surgical approaches and techniques and epilepsy surgery today includes a wide variety of procedures. These can be subdivided into resective, disconnective and neuromodulation procedures and vary from a small, targeted lesionectomy to disconnection/resection of one entire hemisphere. This review will give an overview of the available surgical techniques today and will focus on how the technical advances enable us to map the brain and delineate the critical areas.

Positive pressure therapy for Meniere's syndrome/disease with a Meniett device: a systematic review of randomised controlled trials.

BACKGROUND: Incidence rates of Meniere's syndrome/disease vary considerably from 157 per 100 000 in the United Kingdom to 15 per 100 000 in the United States. A wide range of treatments are used for the treatment of the condition with no consensus on the most effective intervention. OBJECTIVES: To assess the effectiveness of the Meniett device in reducing the frequency and severity of vertigo in Meniere's syndrome/disease. SEARCH METHODS: The Cochrane Ear, Nose and Throat Disorders Group Trials Register; the Cochrane Central Register of Controlled Trials (CENTRAL); PubMed; EMBASE; CINAHL; Web of Science; BIOSIS Previews; Cambridge Scientific abstracts; ICTRP and additional sources for published and unpublished trials were searched. The date of the last search was 13th May 2014. SELECTION CRITERIA: Four randomised controlled trials (RCTs) were identified that compared the efficacy of the Meniett device versus a placebo device in patients with Meniere's 'disease' as defined by the AAOO criterion. DATA COLLECTION AND ANALYSIS: Two review authors independently assessed study eligibility and risk of bias and extracted data. The outcome data were dichotomous for all the included trials. MAIN RESULTS: The four RCTs compared 123 patients with the Meniett device against 114 patients with the placebo device from four RCT's over a follow-up period of 2 weeks to 4 months. There was a significant overall 61% reduction in the frequency of vertigo in both groups (mean no vertigo days per month of 8-3). However, this reduction was not significantly different between the two groups in any study or on meta-analysis [mean difference in vertigo-free days between Meniett and placebo device of 0.77 days over a 1-month period (95% CI - 0.82, 1.83) P = 0.45]. There were also no substantive data to support a greater reduction in the severity of the vertigo or any other outcome with the Meniett device compared with the placebo device. AUTHORS CONCLUSIONS: No evidence was found to justify the use of the Meniett device in Meniere's syndrome/disease.