Orthostatic hypotension following deep brain stimulation in parkinson's disease: a systematic review.

Background: Deep brain stimulation (DBS) is a treatment that may be suitable for patients with Parkinson's disease (PD) with severe motor fluctuations and/or dyskinesias despite optimised medical therapy. DBS has been associated with side effects including deterioration in cognition, verbal fluency and mood. Studies assessing the effect of DBS on orthostatic hypotension (OH) have produced variable results.Objectives: The aim is to summarise peer-reviewed studies that have assessed the effect of DBS on systolic or diastolic BP in PD patients.Methods: The databases PubMed, EMBASE, Medline and Scopus were searched using the terms (Deep brain stimulation OR DBS) AND (hypotension OR hypertension OR blood pressure) on 13 April 2017.Results: Fourteen studies fulfilled the inclusion criteria. Ten studies involved subthalamic nucleus (STN) DBS, three studies globus pallidus interna (GPi) DBS and one study involved DBS of the pedunculopontine nuclei and motor thalamus. The majority of the studies found results indicating that DBS in PD does not worsen OH in PD.Conclusions: Small sample sizes and lack of blinding of outcome assessors means this result should be approached cautiously. Future research may further investigate the effect of GPi DBS on OH and should aim to address these methodological issues.

The Effect of Cochlear Dose on Hearing Preservation After Low-Dose Stereotactic Radiosurgery for Vestibular Schwannomas: A Systematic Review.

Purpose: Despite excellent tumor control after stereotactic radiosurgery (SRS) for vestibular schwannoma (VS), the hearing preservation rate remains unsatisfactorily low. Although many factors have been associated with hearing loss, the dose to cochlea has gained more interest in recent years. However, studies investigating the relation between cochlear dose and hearing outcomes have produced inconsistent results. The purpose of this work is to systematically review the literature and critically analyze the studies that investigated the correlation between cochlear dose and hearing loss. Methods and Materials: A literature search of Ovid MEDLINE, Embase, and Scopus was performed. Studies were included if the SRS dose used was 11 to 14 Gy and included adult patients with sporadic VS, initially serviceable hearing, and at least 24 months of mean or median follow-up. Results: Twenty-one cohort studies and 1 case-control study were eligible for inclusion, and none were considered to be truly prospective. There was substantial heterogeneity between studies in terms of baseline hearing status, cochlear dosimetry, definition and reporting of hearing outcome, and duration of follow-up, limiting comparison between studies and precluding formal meta-analysis. Eleven studies showed a statistically significant correlation between cochlear dose and hearing outcome, but there was considerable variation in the reported cochlear dose parameter that predicted hearing outcome and whether it was an independent predictor. The definition of hearing outcome and whether the outcome variable is continuous or dichotomous have a bearing on the reported correlation between cochlear dose and hearing outcome. Conclusions: Whether cochlear dose is a predictor of hearing preservation after SRS for VS could not be unequivocally determined. Future studies should use consistent cochlear dosimetry and hearing outcomes for reliable assessment. In the meantime, based on currently available data, a practical approach will be to aim for a mean cochlear dose <4 to 6 Gy without compromising tumor dose.

LINAC stereotactic radiosurgery for brain arteriovenous malformations: An updated single centre analysis of outcomes.

Arteriovenous malformations (AVM) of the brain are congenital, high pressure vascular malformations, which are at risk of haemorrhage. Stereotactic radiosurgery (SRS) can obliterate the nidus by delivering a precise high dose of ionising radiation in a single fraction. This paper updates long term AVM obliteration rates, time to obliteration and retreatment outcomes in LINAC delivered SRS treatment at the Royal Adelaide Hospital. A retrospective review of a prospectively maintained AVM SRS database supplemented by clinical case notes, patient correspondence and electronic medical records was performed. 89 AVMs received primary SRS treatment for which the crude obliteration rate was 61% (68% for 79 patients with adequate follow up). Higher marginal dose, smaller nidus size and lower Pollock-Flickinger (PF) score were significantly associated with AVM obliteration. The crude obliteration rates for patients with adequate follow-up and AVM diameter < 3 cm vs ≥ 3 cm were 76% vs 48%, respectively, and 93% with PF score < 1.0. Median time to obliteration was 36 months. Higher dose and lower PF score were associated with earlier obliteration. The crude obliteration rate after second SRS was 56% (9/16 patients) and no significant associations were found. These obliteration rates after primary and retreatment LINAC SRS are comparable to other studies. Marginal dose and PF score were the main predictors of obliteration overall as well as early (<36 months) obliteration.

Substance P immunoreactivity increases following human traumatic brain injury.

Recent experimental evidence suggests that neuropeptides, and in particular substance P (SP), are released following traumatic brain injury (TBI) and may play a significant role in the aetiology of cerebral edema and increased intracranial pressure. Whether SP may play a similar role in clinical TBI remains unknown and was investigated in the current study. Archival post-mortem material was selected from patients who had sustained TBI, had died and had undergone post-mortem and detailed neuropathological examination (n = 13). A second cohort of patients who had died, but who showed no neuropathological abnormality (n = 10), served as case controls. Changes in SP immunoreactivity were examined in the cerebral cortex directly beneath the subdural haematoma in 7 TBI cases and in proximity to contusions in the other 6 cases. Increased SP perivascular immunoreactivity was observed after TBI in 10/13 cases, cortical neurones in 12/13 and astrocytes in 10/13 cases. Perivascular axonal injury was observed by amyloid precursor protein (APP) immunoreactivity in 6/13 TBI cases. Co-localization of SP and APP in a small subset of perivascular fibres suggests perivascular axonal injury could be a mechanism of release of this neuropeptide. The abundance of SP fibres around the human cerebral microvasculature, particularly post capillary venules, together with the changes observed following TBI in perivascular axons, cortical neurones and astrocytes suggest a potentially important role for substance P in neurogenic inflammation following human TBI.

Precision and accuracy of stereotactic targeting in patients undergoing repeat stereotactic surgery.

BACKGROUND/AIMS: Accurate and precise stereotactic targeting is crucial in obtaining the best outcome for patients undergoing functional neurosurgical procedures. METHODS: We calculated the precision and accuracy of stereotactic targeting in 20 consecutive patients who underwent repeat stereotactic surgery from January 2001 to December 2007 at one institution. Two sets of target coordinates were calculated for each patient undergoing repeat surgery from their magnetic resonance images and using Stealth Station and Framelink software. The 1st target coordinate was the initial stereotactic lesion or known functional electrode contact and the 2nd was the computer-calculated coordinate of the selected functional target (ventrointermediate, globus pallidus internus, or subthalamic nucleus ) for the repeat surgery. RESULTS: All patients had a good functional outcome following the initial surgery. Mean differences between coordinates (for all stereotactic targets combined) were 1.35, 1.18 and 1.28 mm for X, Y and Z, respectively. The absolute difference between target points was 2.77 mm. CONCLUSION: This demonstrates a high level of precision and accuracy with contemporary frame-based neuronavigation and stereotactic techniques. Similar data can be easily collected and analyzed for auditing purposes at any neurosurgical center to ensure optimal outcome for patients.

Postoperative headache following treatment of vestibular schwannoma: A literature review.

Vestibular schwannoma (VS) is a brain tumour arising from Schwann cells that is typically closely associated with the vestibulocochlear nerve. Post-operative headaches (POH) are a potentially common complication of surgery for VS. Greatly differing rates of POH have previously been reported, particularly with different surgical approaches. The aim of this review is to identify and summarise the available peer-reviewed evidence on rates of POH following operative (or radiosurgery) treatment for VS, in addition to information about the treatment and prognosis of POH in these patients. A systematic search was conducted of Pubmed, Medline, Scopus and EMBASE in April 2017 using the medical subject headings (acoustic neuroma OR vestibular schwannoma) AND headache. Eligibility determination and data extraction were performed in duplicate with standardised forms. POH is common following surgery for VS. Differing rates of POH have been reported with different management approaches, patient age and tumour size. There are relatively few studies that have directly compared the rates of POH with different surgical approaches. The retrosigmoid approach with craniotomy appears to have lower rates of POH than when the retrosigmoid approach is performed with craniectomy. Patients under the age of 65 and with tumours <1.5 cm in size appear to have a higher risk of POH. The most commonly documented management of POH involves simple analgesia, although the majority of patients report this treatment is of only minimal benefit. Further prospective studies comparing rates of POH following different surgical approaches and radiosurgery are required.

TOOTH (The Open study Of dental pulp stem cell Therapy in Humans): Study protocol for evaluating safety and feasibility of autologous human adult dental pulp stem cell therapy in patients with chronic disability after stroke.

RATIONALE: Stroke represents a significant global disease burden. As of 2015, there is no chemical or biological therapy proven to actively enhance neurological recovery during the chronic phase post-stroke. Globally, cell-based therapy in stroke is at the stage of clinical translation and may improve neurological function through various mechanisms such as neural replacement, neuroprotection, angiogenesis, immuno-modulation, and neuroplasticity. Preclinical evidence in a rodent model of middle cerebral artery ischemic stroke as reported in four independent studies indicates improvement in neurobehavioral function with adult human dental pulp stem cell therapy. Human adult dental pulp stem cells present an exciting potential therapeutic option for improving post-stroke disability. AIMS: TOOTH (The Open study Of dental pulp stem cell Therapy in Humans) will investigate the use of autologous stem cell therapy for stroke survivors with chronic disability, with the following objectives: (a) determine the maximum tolerable dose of autologous dental pulp stem cell therapy; (b) define that dental pulp stem cell therapy at the maximum tolerable dose is safe and feasible in chronic stroke; and (c) estimate the parameters of efficacy required to design a future Phase 2/3 clinical trial. METHODS AND DESIGN: TOOTH is a Phase 1, open-label, single-blinded clinical trial with a pragmatic design that comprises three stages: Stage 1 will involve the selection of 27 participants with middle cerebral artery ischemic stroke and the commencement of autologous dental pulp stem cell isolation, growth, and testing in sequential cohorts (n = 3). Stage 2 will involve the transplantation of dental pulp stem cell in each cohort of participants with an ascending dose and subsequent observation for a 6-month period for any dental pulp stem cell-related adverse events. Stage 3 will investigate the neurosurgical intervention of the maximum tolerable dose of autologous dental pulp stem cell followed by 9 weeks of intensive task-specific rehabilitation. Advanced magnetic resonance and positron emission tomography neuro-imaging, and clinical assessment will be employed to probe any change afforded by stem cell therapy in combination with rehabilitation. SAMPLE SIZE ESTIMATES: Nine participants will step-wise progress in Stage 2 to a dose of up to 10 million dental pulp stem cell, employing a cumulative 3 + 3 statistical design with low starting stem cell dose and subsequent dose escalation, assuming that an acceptable probability of dose-limiting complications is between 1 in 6 (17%) and 1 in 3 (33%) of patients. In Stage 3, another 18 participants will receive an intracranial injection with the maximum tolerable dose of dental pulp stem cell. OUTCOMES: The primary outcomes to be measured are safety and feasibility of intracranial administration of autologous human adult DPSC in patients with chronic stroke and determination of the maximum tolerable dose in human subjects. Secondary outcomes include estimation of the measures of effectiveness required to design a future Phase 2/3 clinical trial.

When is an acoustic neuroma not an acoustic neuroma? Pitfalls for radiosurgeons.

INTRODUCTION: Because acoustic neuroma (AN), also termed vestibular schwannoma, constitutes by far the commonest intracranial schwannoma and cerebello-pontine angle (CPA) tumour, there is a risk of overlooking rarer alternative diagnoses with similar clinical and/or radiological features. The purpose of this article is to highlight to radiosurgeons the potentially serious implications of this problem through illustrative case studies. METHODS: Our linac stereotactic radiosurgery (SRS) technique has been previously described, with stereotactic headring fixation and treatment delivered via cones or micro-multileaf collimators using multiple arcs or static beams. RESULTS: Between November 1993 and October 2014, we treated 132 patients referred with a clinical diagnosis of AN, the vast majority with 12 Gy marginal dose. Three of these (2.3%), evident either at the time of treatment (2) or subsequently (1), had features instead consistent with cochlear schwannoma, facial schwannoma and meningioma, respectively. Each warranted significant modification to standard AN outlining and fields. The meningioma progressed due to geographic miss. One other patient with recurrent facial schwannoma (not yet needing SRS) was also referred with an incorrect diagnosis of AN. CONCLUSION: When rare variants of common medical problems are not identified before referral, there is a risk that 'blinkering' can lead to misdiagnosis and suboptimal treatment. Radiosurgeons need to be particularly mindful of this issue with AN, which can mimic several other tumours occurring in the CPA region, albeit with different patterns of spread. Optimal imaging, high-quality radiology reporting and neuroradiology input at the time of SRS planning within the setting of a specialised multidisciplinary team are highly desirable.

Surgical management of cerebral metastases from melanoma: outcome in 147 patients treated at a single institution over two decades.

OBJECT: The aim of this study was to review the outcome of patients who underwent surgery for treatment of cerebral metastatic melanoma. METHODS: A retrospective analysis was performed in 147 patients with cerebral metastases from melanoma who were treated surgically at a single institution between 1979 and 1999. Almost all patients underwent postoperative wholebrain radiation therapy. The mean patient age was 53 years (range 17-76 years); 69% of patients were male. A single cerebral metastasis was identified in 84% of patients, although 56% had synchronous extracranial metastases. The 30-day postoperative mortality rate was 2% and neurological symptoms resolved or improved in 78% of patients. Recurrence of intracerebral disease was seen in 55% of patients and 26% died of intracerebral metastases. Twenty-four patients underwent reoperation for recurrent cerebral disease. The median survival duration from the time of surgery for all patients was 8.5 months; the 3- and 5-year survival rates were 9% and 5%, respectively. Factors that significantly influenced survival on univariate analysis were the number of cerebral metastases (p = 0.015), a macroscopically complete excision (p < 0.05), and reoperation for recurrence (p = 0.02). The presence of extracranial metastases did not significantly influence survival. On multivariate analysis only the number of cerebral metastases significantly affected survival (p = 0.04). CONCLUSIONS: For the majority of patients with cerebral metastases from melanoma, surgery with adjuvant radiation therapy is a treatment option that improves neurological symptoms and produces minimal morbidity. Long-term survival (> 3 years) most likely occurs in patients with a single cerebral metastasis and no demonstrable extracranial disease. Reoperation for recurrent cerebral disease may be appropriate in selected cases.

LINAC radiosurgery for cerebral arteriovenous malformations: a single centre prospective analysis and review of the literature.

Stereotactic radiosurgery (SRS) is a well established, minimally invasive treatment option for patients diagnosed with cerebral arteriovenous malformations (AVM). We present the experience in linear accelerator-based SRS for cerebral AVM treated over 14 years. We prospectively followed 67 patients with 69 AVM treated with SRS from 1994 to 2008, inclusive. The mean patient age was 37 years (range 7-69) with 36 women and 31 men. The median AVM size, as defined by maximal diameter, was 2.5 cm (range 0.5-4.6 cm) and the median marginal dose was 18 Gy in one fraction. The crude angiographic obliteration rate was 55% with a 3 and 5 year actuarial rate of 39% and 65%, respectively. Median time to obliteration was 4.2 years. Higher treatment dose (p<0.0001) and smaller maximal AVM diameter (p=0.002) were associated with an increased obliteration rate. There were no deaths from treatment. Post-treatment neurological complications occurred in 10 patients (15%) including hemorrhage in two. Twelve patients (18%) required a second SRS procedure. Larger AVM diameter was associated with increased odds of requiring re-treatment (p=0.02). Radiosurgery for intracerebral AVM is a non-invasive therapeutic option with low morbidity and a reasonable likelihood of nidus obliteration. Treatment dose and AVM diameter are the main determinants of obliteration.

Enhanced intrinsic radiosensitivity after treatment with stereotactic radiosurgery for an acoustic neuroma.

Enhanced radiosensitivity is an uncommon phenomenon attributable to deficient DNA repair after radiotherapy which can be assessed with the γ-H2AX assay. Reports of radiosensitivity after stereotactic radiosurgery (SRS) are uncommon. We describe a case where the clinical, radiological and laboratory findings suggest enhanced radiosensitivity after SRS for an acoustic neuroma.

Hearing preservation after low dose linac radiosurgery for acoustic neuroma depends on initial hearing and time.

PURPOSE: To assess long term outcomes and factors determining hearing preservation after low dose linac stereotactic radiosurgery (SRS) for acoustic neuroma (AN) at the Royal Adelaide Hospital using prospectively collected data. MATERIAL AND METHODS: Between 1994 and 2010, 102 patients had SRS for AN. Five patients had neurofibromatosis type 2, six sporadic cases had relapsed after surgery, and the remaining 91 sporadic cases had primary SRS. Dose was 12 or 14 Gy. Sustained changes ≥ 2 mm in any diameter were deemed significant, and useful hearing was defined as inter-aural pure tone average (PTA) ≤ 50 dB. Possible prognostic factors for hearing retention were tested by dividing the patients at pre-specified cutpoints: age (60 years), maximum tumour diameter (20mm), initial PTA (20 dB) and dose (12 vs 14 Gy). RESULTS: Eighty-four of the 91 sporadic primary SRS cases were evaluable for tumour control with at least one post-treatment MRI. Their median follow-up was 65 mo (range 10-184 mo). Eighty-two (97.6%) were controlled, the remaining two requiring salvage surgery for progression at 5.75 and 9.75 years. Also, one of the post-operative cases required surgery at 2.1 years after SRS. For the 50 sporadic primary SRS patients with initially useful hearing, median age was 56 (range 21-76), median initial PTA 16 dB (range -11 to +45 dB) and median tumour diameter 21 mm (range 10-33 mm). Four received 14 Gy, the rest 12 Gy. After SRS, 19 patients (38%) retained useful hearing. The Kaplan-Meier estimated preservation rate at 5 years was 50% (95% CI 36-64%) but by 10 years, this had fallen to 23% (95% CI 12-41%). On univariate analysis, the only significant factor was initial PTA (P < 0.0001). The estimated risk of hearing loss after SRS for patients with initial PTA ≥ 20 dB was 5.0 (95% CI 2.2-11.2) times that with PTA < 20 dB. CONCLUSIONS: Tumour control was excellent (99/102=97% freedom from surgical salvage). Hearing preservation was strongly dependent on initial PTA, but there was a steady fall-off in hearing out to at least 10 years.

Long-term outcome following ilioinguinal neurectomy for chronic pain.

OBJECT: Ilioinguinal neuralgia is one cause of chronic groin pain following inguinal hernia repair, and it affects approximately 10% of patients. Selective ilioinguinal neurectomy is one proposed treatment option for carefully selected patients. The goal of this study was to determine the long-term outcome of patients who underwent selective ilioinguinal neurectomy for chronic post-hernia pain. METHODS: The authors retrospectively reviewed the clinical assessment, surgical treatment, and long-term outcome in 26 patients with ilioinguinal neuralgia who underwent selective ilioinguinal neurectomy performed by the senior author (K.J.B.) at Oregon Health & Science University between 1998 and 2008. Data were collected from patient charts and a follow-up telephone questionnaire. RESULTS: Twenty-six patients (14 men and 12 women) had a clinical diagnosis of ilioinguinal neuralgia based on a history of radiating neuropathic groin, medial thigh, and genitalia pain. One patient had bilateral disease (therefore there were 27 surgical cases). A selective nerve block was performed in 21 (81%) of 26 patients and was positive in 20 (77%) of the 26. In all but 2 patients, pain onset followed abdominal surgery (for hernia repair in 18 patients), and was immediate in 16 (67%) of 24 patients. The mean patient age was 48.7 years, and the mean duration of pain prior to neurosurgical consultation was 3.9 years. Surgery was performed after induction of local or general anesthesia in 17 and 10 cases, respectively. The ilioinguinal nerve was identified in 25 cases, and the genitofemoral nerve in 2, either entrapped in mesh, scar, or with obvious neuroma (22 of 27 cases). The identified nerve was doubly ligated, cut, and buried in muscle at its most proximal point. At the 2-week follow-up evaluations, 14 (74%) of 19 patients noted definite pain improvement. Nineteen (73%) of the 26 patients were contacted by telephone and agreed to participate in completing long-term follow-up questionnaires. The mean follow-up duration was 34.78 months. Return of pain was reported by 13 (68%) of 19 patients. Using a verbal numerical rating scale (0-10), pain was completely relieved in 27.8%, better in 38.9%, no better in 16.7%, and worse in 16.7% of patients. CONCLUSIONS: Ilioinguinal neurectomy is an effective and appropriate treatment for selected patients with iatrogenic ilioinguinal neuralgia following abdominal surgery. Although a high proportion of patients reported some long-term recurrence of pain, complete or partial pain relief was achieved in 66.7% of the patients observed.

Preoperative magnetic resonance imaging in Type 2 trigeminal neuralgia.

OBJECT: Trigeminal neuralgia (TN) is a neuropathic pain syndrome that is often associated with neurovascular compression of the trigeminal nerve and may be effectively treated with microvascular decompression (MVD). The authors used high-resolution MR imaging with 3D reconstruction in patients with constant facial pain (Type 2 TN) to determine the presence/absence of neurovascular compression and thus a potential MVD benefit. They retrospectively contacted patients to evaluate outcome. METHODS: All patients who reported spontaneous onset of constant facial pain (Type 2 TN), which occurred at least 50% of the time, who had undergone high-resolution 3-T MR imaging with 3D reconstruction were retrospectively selected for this study. Clinical history, facial pain questionnaire data, physical examination findings, and results from 3-T 3D MR imaging reconstruction were recorded for all patients. Intraoperative findings and clinical pain outcome were recorded for all patients who underwent MVD. RESULTS: Data obtained in 27 patients were assessed. On the basis of history and 3D MR imaging reconstruction findings, 13 patients were selected for MVD (Group A) and 14 underwent conservative treatment (Group B). Typical or suspected artery- or vein-induced neurovascular compression was predicted preoperatively in 100% of Group A patients and in 0% of Group B patients. At the time of MVD, definitive neurovascular compression was confirmed in 11 (84.6%) of 13 Group A patients. Following MVD, facial pain was completely relieved in 3 (23%), improved in 7 (53.8%), and no better in 3 (23%) of 13 Group A patients. A history of episodic (Type 1 TN) pain at any time was reported in 100 and 50% of Group A and Group B patients, respectively. A Type 1 TN pain component was reportedly improved/relieved in all Group A patients, but the Type 2 TN pain component was improved in only 7 (53.8%) of 13 patients. The mean postoperative follow-up duration was 13 months. CONCLUSIONS: High-resolution 3D MR imaging reconstruction in patients with constant facial pain (Type 2 TN) can help determine the presence/absence of neurovascular compression. Surgical selection based on both clinical and radiological criteria has the potential to improve surgical outcome in patients with Type 2 TN who may potentially benefit from MVD. However, even in such selected patients, pain relief is likely to be incomplete.

The Glass Half Empty or Half Full-How Effective Are Long-Term Intrathecal Opioids in Post-herpetic Neuralgia? A Case Series and Review of the Literature.

Objectives. Post-herpetic neuralgia (PHN) is a painful complication of herpes zoster infection and a common cause of chronic severe pain in elderly and/or debilitated patients. Although a wide range of treatments have been tried, a substantial number of patients continue to experience pain which remains refractory to all therapies. Increasingly, studies have demonstrated that oral opioids can have a beneficial effect on neuropathic pain. However, to date, few studies have examined the potential benefit(s) of chronic intrathecal opioids in the treatment of PHN. Methods. Long-term outcome results of four PHN patients who had a successful intrathecal opioid trial and underwent implantation of an intrathecal opioid pump were examined. Data were analyzed using univariate analysis of variance. Results. Duration of continuous intrathecal opioid therapy ranged from five to 50 months and mean pain reduction was 41% (range 27-50%) as measured by a verbal pain score (0-100), with the greatest benefit noticed earlier in therapy. Mean 24-hour intrathecal morphine dose was 2.29 mg (range 0.78-3.94 mg). Intrathecal therapy was discontinued in two patients because of opioid side-effects, depression, and loss of efficacy. Revision surgery was required in two cases. Patients most commonly reported improvement in the deep component of their pain, next allodynia, and less so superficial lancinating pain. Conclusions. In conclusion, while a complex therapy, long-term use of intrathecal opioids is well tolerated, doses are titratable, administration is safe, and may help relieve severe short- and long-term neuropathic pain in selected PHN patients. Whether the addition of newer investigational intrathecal agents could improve these results is yet to be determined.

Surgical management of spinal catheter granulomas: operative nuances and review of the surgical literature.

OBJECTIVE: Spinal catheter granulomas are a rare and, most likely, underreported complication of intrathecal opioid therapy. Such granulomas can be associated with devastating neurological sequelae if not treated in a timely fashion. Most neurosurgeons, however, are unlikely to have had experience in the surgical management of this condition. CLINICAL PRESENTATION: The authors present 3 surgical cases of patients with spinal catheter granulomas with neurological deficits. One patient's intraoperative video illustrates the challenges of diagnosis, radiological assessment, and surgery for spinal catheter granulomas. INTERVENTION: All 3 patients had implanted opioid pumps for management of chronic spinal pain secondary to fracture, tethered cord, and back pain. Increasing back pain and a progressive myelopathy was observed in all patients. A clear radiological diagnosis was made more difficult because of instrumentation artifact in 1 case and claustrophobia in another. Computed tomographic myelography was necessary in 1 case. The surgical findings were: 1 extradural catheter with granuloma and 2 intradural catheters encased with granuloma and adherent to the cord. The extradural catheter was trimmed of granuloma and replaced intradurally in 1 case. The patients with intradural catheter granulomas required judicious dissection of the granulomas from the dorsum of the cord, duroplasty, and catheter section. Critical intraoperative stages were recorded and are presented in digital movie format. Two patients had neurological improvement after surgery; however, 1 patient remained paraplegic. The 2 patients with catheter section required opioid withdrawal treatment. CONCLUSION: The operative management of spinal intrathecal granulomas associated with opioid infusion pumps can be challenging and depends on a high degree of clinical suspicion, imaging results, and operative findings.

Sensitivity of high-resolution three-dimensional magnetic resonance angiography and three-dimensional spoiled-gradient recalled imaging in the prediction of neurovascular compression in patients with hemifacial spasm.

OBJECT: Hemifacial spasm is a clinical syndrome caused by vascular compression of the facial nerve in the cerebellopontine angle, which can be relieved by surgical intervention. Advances in medical imaging technology allow for direct visualization of the offending blood vessels in hemifacial spasm and similar conditions (such as trigeminal neuralgia). The utility of high resolution 3D MR angiography and 3D spoiled-gradient recalled (SPGR) imaging sequences for surgical decision-making in hemifacial spasm, as measured by sensitivity, specificity, and positive and negative predictive values, has not been previously determined. METHODS: A retrospective review was undertaken of 23 patients with hemifacial spasm who underwent operations between January 2001 and December 2006 at Oregon Health & Science University. All patients underwent preoperative high-resolution 3D MR angiography and 3D SPGR imaging. The sensitivity of the SPGR imaging/MR angiography interpretation of neurovascular compression (NVC) by both a neurosurgeon and 2 neuroradiologists was determined in relation to the presence of actual NVC during surgery. RESULTS: All patients were found to have NVC at surgery. After review by a neurosurgeon and 2 neuroradiologists, imaging data from 19 of the 23 patients were evaluated. The neurosurgeon's interpretation had a sensitivity of 79% and a positive predictive value (PPV) of 100%. The first neuroradiologist's interpretation had a sensitivity of 21% with a PPV of 100%. Further interpretation by a blinded second neuroradiologist with expertise in MR imaging of hemifacial spasm and trigeminal neuralgia was conducted, and sensitivity was 59% and PPV was 100%. Specificity was not determined because there were no true negative cases. The negative predictive value was 0% for both the neurosurgeon's and neuroradiologists' evaluations. CONCLUSIONS: Although high-resolution 3D MR angiography and 3D SPGR imaging was helpful in providing information about the anatomical relationship of cranial nerve VII and surrounding blood vessels, the authors determined that in the case of hemifacial spasm these types of imaging did not influence preoperative surgical decisionmaking.