Patient Cranial Angle and Intrafractional Stability in CyberKnife Robotic Radiosurgery: A Retrospective Analysis.

Purpose: The aim of this study was to investigate whether variations in cranial angles and treatment accuracy during CyberKnife robotic radiosurgery necessitate adjustment of the margins of the planning target volume. Patients and Methods: Data from 66 patients receiving CyberKnife treatment for brain tumors were retrospectively analyzed. Patients were immobilized using a thermoplastic mask and headrest. The cranial angle was measured on planning CT and patients were divided into 2 groups: ≤10° (Group A) and >10° (Group B). Intrafractional motion was recorded using the CyberKnife tracking system over 50 min. Translational and rotational errors were compared between groups, and planning target volume margins were calculated. Results: In Group A, significant translational error differences were found along with the X-axis over time (P < .02). In Group B, significant differences occurred along with the Z-axis (P < .03). No significant rotational or 3-dimensional vector differences were found in either group. Group A had significantly lower Y-axis (P < .045) and roll axis (P < .005) errors compared to Group B. Estimated planning target volume margins in Group A were 0.56 mm (X), 0.46 mm (Y), and 0.47 mm (Z). In Group B, margins were 0.62 mm (X), 0.48 mm (Y), and 0.46 mm (Z). Margins covering 95% of intrafraction motion were 0.49 to 0.50 mm (X, Y, Z) and 0.69 mm (3-dimensional vector) for Group A, and 0.48 to 0.60 mm and 0.79 mm for Group B. With a 1-mm margin, complete coverage was achieved in Group A while 2.1% of vectors in Group B exceeded 1 mm. Conclusion: Adjusting cranial angle to ≤10° during thermoplastic mask molding provided better or similar intrafractional stability compared to >10°.

A Model for Predicting the Duration of Viral Shedding in Patients Who Had Been Hospitalized with Mild COVID-19: A Single-Center Retrospective Study.

Background: Clinical decision-making is enhanced by the development of a mathematical model for prognosis prediction. Screening criteria associated with viral shedding time and developing a prediction model facilitate clinical decision-making and are, thus, of great medical value. Methods: This study comprised 631 patients who were hospitalized with mild COVID-19 from a single center and 30 independent variables included. The data set was randomly divided into the training set (80%) and the validation set (20%). The outcome variable included viral shedding time and whether the viral shedding time >14 days, LASSO was used to screen the influencing factors. Results: There were 321 males and 310 females among the 631 cases, with an average age of 62.1 years; the median viral shedding time was 12 days, and 68.8% of patients experienced viral shedding within 14 days, with fever (50.9%) and cough (44.2%) being the most common clinical manifestations. Using LASSO with viral shedding time as the outcome variable, the model with lambda as 0.1592 (λ = 0.1592) and 13 variables (eg the time from diagnosis to admission, constipation, cough, hs-CRP, IL-8, IL-1ß, etc.) was more accurate. Factors were screened by LASSO and multivariable logistic regression with whether the viral shedding time >14 days as the outcome variable, five variables, including the time from diagnosis to admission, CD4 cell count, Ct value of ORF1ab, constipation, and IL-8, were included, and a nomogram was drawn; after model validation, the consistency index was 0.888, the AUC was 0.847, the sensitivity was 0.744, and the specificity was 0.830. Conclusion: A clinical model developed after LASSO regression was used to identify the factors that influence the viral shedding time. The predicted performance of the model was good, and it was useful for the allocation of medical resources.

Evaluation of the Position Error of Wearing Surgical Masks During Radiotherapy in Head and Neck Cancer Patients.

Purpose: Wearing a mask during the coronavirus disease 2019 epidemic (COVID-19) is a preventive way to reduce droplet and aerosol transmission. The purpose of this study was to evaluate the position error of wearing a surgical mask during radiotherapy in head and neck cancer patients. Patients and Methods: We collected and analyzed 2351 kV X-ray image records of 81 patients with head and neck cancer who underwent image-guided radiotherapy (IGRT). Patients with/without a surgical mask were divided into the head-neck (HN) mask group and head-neck-shoulder (HNS) mask group. The position error in the X (left-right), Y (superior-inferior), Z (anterior-posterior), 3D (three dimensional) vectors, as well as the pitch and yaw axes were compared between the four groups. Results: We found that patients wearing surgical masks in the HN mask group showed no significant differences in the mean position error of the different types of headrest (p>0.05). In the HNS mask group, only the type C headrest group showed significant differences (P < 0.05). The X axis values were -0.05±0.07 and -0.11± 0.01 cm (P = 0.04), and the pitch axis values were 0.34±0.29° and 0.83±0.08° (P = 0.01). Conclusion: The mean position error of most patients wearing surgical masks was not greater than patients without a surgical mask. Patients wearing while receiving treatment is a low-cost and easy-to-implement prevention method.

Removal of chlortetracycline from water using spent tea leaves-based biochar as adsorption-enhanced persulfate activator.

Antibiotic compounds have caused serious environmental concerns. In this study, we developed an effective technology for treatment of chlortetracycline (CTC), a widely used antibiotic compound. A natural heteroatom-doped spent tea leaves-based biochar (STLB) with excellent adsorption and catalytic property was prepared by simple thermal treatment. An adsorption-promoted persulfate-based advanced oxidation process (PS-AOP) using STLB was studied for CTC removal. The results showed that the as-prepared STLB presented favorable adsorption affinity towards CTC with the maximum adsorption capacity of 627 mg g-1. Meanwhile, CTC enriched on the surface of STLB was good for in-situ decomposition of CTC and nearly 97.4 % of CTC was removed within 30 min of pre-adsorption and 60 min of subsequent degradation. The STLB had excellent recyclability and wide pH tolerance range of 3.0-9.0 in combined pre-adsorption and PS-AOP. Reactive oxygen species analysis confirmed that CTC degradation was mainly due to non-radical (singlet oxygen, 1O2) and radicals (SO4- and OH). This study suggests that STLB is a promising adsorption-enhanced PS activator for the treatment of refractory wastewater and also provides a strategy of waste control by spent tea leaves.

Effect of Electronic Clinical Decision Support on Imaging for the Evaluation of Acute Low Back Pain in the Ambulatory Care Setting.

OBJECTIVES: To assess the effectiveness of a clinical decision support tool consisting of an electronic medical record best practice alert (BPA) on the frequency of lumbar imaging in patients with acute low back pain in the ambulatory care setting, and to explore why providers order imaging outside of clinical guidelines. METHODS: On March 23, 2016, we implemented a BPA pop-up alert that informed the ordering physician of the Choosing Wisely recommendation to not order imaging within the first 6 weeks of low back pain in the absence of red flags. We calculated imaging rates 1 year before and after implementation of the BPA. To override the BPA, providers could ignore the alert or explain their rationale for ordering imaging using either preset options or a free-text submission. We tracked preset options and manually reviewed 125 free-text submissions. RESULTS: Significant decreases in both total imaging rate (9.6% decrease; P = 0.02) and magnetic resonance imaging rate (14.9% decrease; P < 0.01) were observed after implementation of the BPA. No change was found in the rates of X-ray or computed tomography scan orders. Almost two-thirds (64%) of the providers used preset options in overriding the BPA, and 36% of the providers entered a free-text submission. Among those providers using a free-text submission, 56% entered a non-guideline-supported rationale. CONCLUSIONS: The present study demonstrates the effectiveness of a simple, low-cost clinical decision support tool in reducing imaging rates for patients with acute low back pain. We also identify reasons why providers order imaging outside of clinical guidelines.

Risk Adjustment Instruments in Administrative Data Studies: A Primer for Neurosurgeons.

With the increasing interest in big data and health services research, use of administrative databases is becoming commonplace in health care studies, including in neurosurgery. Administrative data offer the unique advantage of accessing large amounts of information previously collected from a population-based sample with geographic diversity. When using administrative data sets, researchers can benefit from application of risk adjustment instruments, which help stratify patients and tailor the original sample for specific research questions. The Charlson Comorbidity Index and Elixhauser Comorbidity Index are 2 of the most common indices. The Pediatric Medical Complexity Algorithm and Clinical Classification Software are other promising tools. Understanding of these tools may assist neurosurgeons who wish to critically assess research findings relevant to their clinical practice. In this review, an overview is presented of risk adjustment tools commonly used in adult as well as pediatric populations and their history, uses, limitations, and applications in neurosurgical research are summarized.

Prognostic Value of D-Dimer in Patients with Diffuse Large B-cell Lymphoma: A Retrospective Study.

This study evaluated the significance of serum D-Dimer for predicting survival of patients with diffuse large B-cell lymphoma (DLBCL). We analyzed the clinical data from 113 patients who were newly diagnosed with DLBCL at Tongji Hospital from January 2012 to January 2016. The results indicated that there were higher levels of D-Dimer in DLBCL patients with the following characteristics: stage III/IV, lymphocyte monocyte ratio (LMR) <2.27, lactate dehydrogenase (LDH) > upper limit of normal (ULN), albumin (ALB) < 35 g/L, and anemia. After the first chemotherapeutic regimen, D-Dimer was significantly decreased concomitantly with LDH. Cox univariate regression analysis showed that the overall survival (OS) was negatively affected by the following factors: age > 60 years, stage III/W, LDH > ULN, LMR < 2.27, anemia and D-Dimer > 0.92. Multivariate analysis showed that only LDH > ULN (P=0.038) and age > 60 years (P=0.047) were independent adverse prognostic factors. However, it was suggested that D-Dimer could be regarded as a marker of high tumor burden and a potential prognostic screening tool for patients with DLBCL, not otherwise specified (NOS).

Patient Satisfaction and Press Ganey Scores for Spine Versus Nonspine Neurosurgery Clinics.

STUDY DESIGN: Retrospective survey review. OBJECTIVE: We seek to evaluate satisfaction scores in patients seen in neurosurgical spine versus neurosurgical nonspine clinics. SUMMARY OF BACKGROUND DATA: The Press Ganey survey is a well-established metric for measuring hospital performance and patient satisfaction. These measures have important implications in setting hospital policy and guiding interventions to improve patient perceptions of care. METHODS: Retrospective Press Ganey survey review was performed to identify patient demographics and patient visit characteristics from January 1st, 2012 to October 10th, 2017 at Stanford Medical Center. A total of 40 questions from the Press Ganey survey were investigated and grouped in categories addressing physician and nursing care, personal concerns, admission, room, meal, operating room, treatment and discharge conditions, visitor accommodations and overall clinic assessment. Raw ordinal scores were converted to continuous scores of 100 for unpaired student t test analysis. We identified 578 neurosurgical spine clinic patients and 1048 neurosurgical nonspine clinic patients. RESULTS: Spine clinic patients reported lower satisfaction scores in aggregate (88.2 vs. 90.1; P=0.0014), physician (89.5 vs. 92.6; P=0.0002) and nurse care (91.3 vs. 93.4; P=0.0038), personal concerns (88.2 vs. 90.9; P=0.0009), room (81.0 vs. 83.1; P=0.0164), admission (90.8 vs. 92.6; P=0.0154) and visitor conditions (87.0 vs. 89.2; P=0.0148), and overall clinic assessment (92.9 vs. 95.5; P=0.005). CONCLUSIONS: This study is the first to evaluate the relationship between neurosurgical spine versus nonspine clinic with regards to patient satisfaction. The spine clinic cohort reported less satisfaction than the nonspine cohort in all significant questions on the Press Ganey survey. Our findings suggest that efforts should be made to further study and improve patient satisfaction in spine clinics. LEVEL OF EVIDENCE: Level III.

Pediatric parapharyngeal infection resulting in cervical instability and occipital-cervical fusion-case report and review of the literature.

Parapharyngeal infection is the most common deep neck space infection in children and, in rare instances, can result in bony destruction of the cervical spine. We report one such case that required occipital to cervical fusion and halo-vest fixation. We also review the literature and discuss the etiology, diagnosis, and treatment options for managing pediatric cervical bony destruction secondary to infection.

Minimally invasive lumbar pedicle screw fixation using cortical bone trajectory - Screw accuracy, complications, and learning curve in 100 screw placements.

Cortical bone trajectory (CBT) is a novel pedicle insertion technique with comparable or superior mechanical properties and reduced invasiveness compared to traditional methods. We describe the screw accuracy, complications, and learning curve associated with CBT use. A prospective cohort study was performed involving 22 patients who underwent lumbar fusion with CBT screw placement. A total of 100 cortical screws were placed. Post-operative CT scans were reviewed to assess the adequacy of screw placement and calculate the incidence of vertebral body and pedicle breaches from cortical screw placement. Technique-related complications were examined. The entire surgical cohort was divided into two groups: early experience (first 11 patients) and late experience (last 11 patients), to study the effect of learning curve on CBT screw placement. Medial pedicle breach was observed in 6/100 cases and lateral vertebral body breach was observed in 1/100 cases. The incidence of durotomy related to the technique was 4.5% (N = 1/22). Post-surgical wound infection was seen in 9.1% of patients (N = 2/22). 66.7% (N = 4/6) of medial pedicle breaches, 100% (N = 1/1) of lateral breaches, 100% (N = 1/1) of CBT technique-related CSF leaks, and 100% (N = 2/2) of wound infections occurred in the early experience phase of our study (p = 0.0945). A shift in surgical technique and greater efficiency over time decreased the incidence of overall complications in the late cohort. The difference, however, did not reach statistical significance. A lateralized starting point for the cortical screw on the pars interarticularis and use of smaller diameter screws resulted in fewer medial pedicle out-fractures and breaches.

Transoral Endoscopic Resection of High Cervical Osteophytes with Long-Term Symptom Resolution: Case Series, Imaging, and Literature Review.

BACKGROUND: Anterior cervical osteophytes (ACOs) are a common radiologic finding in the elderly; rarely, they can cause dysphagia, dysphonia, and dyspnea. Symptomatic ACOs are most commonly found between C4 and C7 and much less commonly at higher cervical levels. Here, we present a case series, with an example case of a 57-year-old woman with high cervical osteophytes at C1-C2 causing globus sensation, dysphagia, and dysphonia. Additionally, we provide a literature review regarding the causes, diagnosis, and treatment of ACOs, with a focus on management of high ACOs. CASE DESCRIPTION: A 57-year-old smoker with a history of chronic neck pain and previous cervical spinal instrumentation presented with several months of globus sensation, dysphagia, and dysphonia. Imaging revealed 2 large anterior osteophytes at C1-C2. She underwent endoscopic transoral osteophytectomy, with resolution of symptoms. Five other patients are also presented who underwent similar procedures. CONCLUSIONS: ACOs are a potential cause of dysphagia, and their diagnosis is best made with computed tomographic imaging and oropharyngeal swallow study. Although high ACOs at C1-C2 are a rare finding, here we show with an exemplary case and small case series that they can be effectively treated with transoral endoscopic osteophytectomy.

National Trends for Reoperation in Older Patients with Glioblastoma.

BACKGROUND: Despite multimodal therapies extending patient survival, glioblastoma (GBM) recurrence is all but a certainty. To date, there are few single-center studies of reoperations. Our study aimed to assess GBM reoperation trends nationally in older patients, with emphasis on outcomes. METHODS: The linked Surveillance, Epidemiology, and End Results (SEER)-Medicare database was searched to identify patients 66 years and older with GBM from 1997 to 2010. The primary outcome was survival after diagnosis. Kaplan-Meier curves and multivariate analysis with proportional hazard ratios were used. RESULTS: Three thousand nine hundred sixty-three patients with recurrent GBM who initially received a surgical resection were identified (mean age = 74.7 years). Four hundred ninety-six (12%) of the patients with recurrent GBM underwent at least one reoperation at an average of 7.2 months after the initial diagnosis. Reoperation increased survival in patients compared with those who did not have surgical resection (12 vs. 5 months; P < 0.0001; hazard ratio [HR] = 0.666). Within the reoperated cohort, gross total resection improved median survival over subtotal resection (HR = 0.779). Two or more reoperations upon GBM recurrence improved survival to 17 months (P = 0.002). The overall complication rate was 21.7% in the initial resection-only group, versus 20.4% in the 1-reoperation group and 25.3% in the 2-reoperation group. CONCLUSIONS: Although definitive conclusions cannot be made given the lack of granularity, our national database study supports gross total resection as the initial treatment of choice, followed by reoperation at the time of recurrence, if tolerated, even in older patients.

Cardinal features of superior oblique myokymia: An infrared oculography study.

PURPOSE: Superior oblique myokymia (SOM) is a rare eye movement disorder characterized by unilateral oscillopsia and binocular diplopia. Our study aimed to better understand SOM using infrared oculography. METHODS: We examined and recorded five patients with SOM. RESULTS: Binocular infrared oculography showed that in primary gaze, all patients exhibited torsional oscillations, which worsened in infraduction and abduction and improved in supraduction and adduction. Saccades showed increased downward saccade amplitudes but normal peak velocities. During fixation in primary gaze, removal of target led to extorsion and supraduction, unmasking underlying superior oblique weakness. CONCLUSIONS AND IMPORTANCE: Our data suggest both weakness and activity-dependent hyperactivity of the trochlear motor unit, supporting a model of injury followed by aberrant regeneration.

Differences in Antipsychotic-Related Adverse Events in Adult, Pediatric, and Geriatric Populations.

In recent years, antipsychotic medications have increasingly been used in pediatric and geriatric populations, despite the fact that many of these drugs were approved based on clinical trials in adult patients only. Preliminary studies have shown that the "off-label" use of these drugs in pediatric and geriatric populations may result in adverse events not found in adults. In this study, we utilized the large-scale U.S. Food and Drug Administration (FDA) Adverse Events Reporting System (AERS) database to look at differences in adverse events from antipsychotics among adult, pediatric, and geriatric populations. We performed a systematic analysis of the FDA AERS database using MySQL by standardizing the database using structured terminologies and ontologies. We compared adverse event profiles of atypical versus typical antipsychotic medications among adult (18-65), pediatric (age < 18), and geriatric (> 65) populations. We found statistically significant differences between the number of adverse events in the pediatric versus adult populations with aripiprazole, clozapine, fluphenazine, haloperidol, olanzapine, quetiapine, risperidone, and thiothixene, and between the geriatric versus adult populations with aripiprazole, chlorpromazine, clozapine, fluphenazine, haloperidol, paliperidone, promazine, risperidone, thiothixene, and ziprasidone (p < 0.05, with adjustment for multiple comparisons). Furthermore, the particular types of adverse events reported also varied significantly between each population for aripiprazole, clozapine, haloperidol, olanzapine, quetiapine, risperidone, and ziprasidone (Chi-square, p < 10-6). Diabetes was the most commonly reported side effect in the adult population, compared to behavioral problems in the pediatric population and neurologic symptoms in the geriatric population. We also found discrepancies between the frequencies of reports in AERS and in the literature. Our analysis of the FDA AERS database shows that there are significant differences in both the numbers and types of adverse events among these age groups and between atypical and typical antipsychotics. It is important for clinicians to be mindful of these differences when prescribing antipsychotics, especially when prescribing medications off-label.

CyberKnife stereotactic radiosurgery for the treatment of symptomatic vertebral hemangiomas: a single-institution experience.

OBJECTIVE Symptomatic vertebral hemangiomas (SVHs) are a very rare pathology that can present with persistent pain or neurological deficits that warrant surgical intervention. Given the relative rarity and difficulty in assessment, the authors sought to present a dedicated series of SVHs treated using stereotactic radiosurgery (SRS) to provide insight into clinical decision making. METHODS A retrospective review of a single institution's experience with hypofractionated radiosurgery for SVH from 2004 to 2011 was conducted to determine the clinical and radiographic outcomes following SRS treatment. The authors report and analyze the treatment course of 5 patients with 7 lesions, 2 of which were treated primarily by SRS. RESULTS Of the 5 patients studied, 4 presented with a chief complaint of pain refractory to conservative measures. Three patients reported dysesthesias, and 2 reported upper-extremity weakness. Following radiosurgery, 4 of 5 patients exhibited improvement in their primary symptoms (3 for pain and 1 for weakness), achieving a clinical response after a mean period of 1 year. In 2 cases there was 20%-40% reduction in lesion size in the most responsive dimension as noted on images. All treatments were well tolerated. CONCLUSIONS SRS for SVH is a safe and feasible treatment strategy, comparable to prior radiotherapy studies, and in select cases may successfully confer delayed decompressive effects. Additional investigation will determine future patient selection and how conformal SRS treatment can best be administered.

The effect of postoperative infection on survival in patients with glioblastoma.

OBJECTIVE Glioblastoma is a primary glial neoplasm with a median survival of approximately 1 year. There are anecdotal reports that postoperative infection may confer a survival advantage in patients with glioblastoma. However, only a few case reports in the literature, along with 2 retrospective cohort studies, show some potential link between infection and prolonged survival in patients with glioblastoma. The objective of this study was to evaluate the effect of postoperative infection in patients with glioblastoma using a large national database. METHODS The linked Surveillance, Epidemiology, and End Results (SEER)-Medicare database was searched to identify patients 66 years of age and older with glioblastoma, with and without infection, from 1997 to 2010. The primary outcome was survival after diagnosis. The statistical analysis was performed with a graphical representation using Kaplan-Meier curves, univariate analysis with the log-rank test, and multivariate analysis with proportional hazards modeling. RESULTS A total of 3784 patients with glioblastoma were identified from the database, and from these, 369 (9.8%) had postoperative infection within 1 month of surgery. In patients with glioblastoma who had an infection within 1 month of surgery, there was no significant difference in survival (median 5 months) compared with patients with no infection (median 6 months; p = 0.17). The study also showed that older age, increased Gagne comorbidity score, and having diabetes may be negatively associated with survival. CONCLUSIONS Infection after craniotomy within 1 month was not associated with a survival benefit in patients with glioblastoma.

Cervical Fracture/Subluxation in a Patient with a Prior C2-Sacrum Fusion: Case Report and Review of Literature.

Traumatic injury to an adjacent segment of a previously fused spine is a rare complication of scoliosis surgery. The adjacent spinal segments may be more vulnerable to traumatic fracture or dislocation due to increased strain. We present a patient with prior C2 to sacrum fusion who suffered a C2 fracture/dislocation after falling. A 52-year-old female with a previous C2 to the sacrum fusion for idiopathic scoliosis presented with severe and progressively worsening neck pain after multiple falls. Imaging showed anterior displacement of the C2 vertebral body, fracture of C2, and anterior subluxation of the C1-2 complex on C3. The patient underwent posterior occiput to cervical fusion and reduction of the C1-C2 complex. Our case describes a potential complication of long-segment fusion. Adjacent segments may be more prone to fracture-dislocation because of increased intradiscal pressure and strain. Clinicians should have a high suspicion of fractures in patients with prior spinal fusions in the setting of trauma.

Minimally Invasive Lumbar Pedicle Screw Fixation Using Cortical Bone Trajectory - A Prospective Cohort Study on Postoperative Pain Outcomes.

OBJECTIVE: Our study aims to evaluate the clinical outcomes of cortical screws in regards to postoperative pain. BACKGROUND: Pedicle screw fixation is the current mainstay technique for posterior spinal fusion. Over the past decade, a new technique called cortical screw fixation has been developed, which allows for medialized screw placement through stronger cortical bone. There have been several studies that showed either biomechanical equivalence or superiority of cortical screws. However, there is currently only a single study in the literature looking at clinical outcomes of cortical screw fixation in patients who have had no prior spine surgery. METHODS: We prospectively looked at the senior author's patients who underwent cortical versus pedicle lumbar screw fixation surgeries between 2013 and 2015 for lumbar degenerative disease. Eighteen patients underwent cortical screw fixation, and 15 patients underwent traditional pedicle screw fixation. We looked at immediate postoperative pain, changes in short-term pain (six to 12 weeks post-surgery), and changes in long-term pain (six to eight months). All pain outcomes were measured using a visual analog scale ranging from 1 to 10. Mann-Whitney or Kruskal-Wallis tests were used to measure continuous data, and the Fisher Exact test was used to measure categorical data as appropriate. RESULTS: Our results showed that the cortical screw cohort showed a trend towards having less peak postoperative pain (p = 0.09). The average postoperative pain was similar between the two cohorts (p = 0.93). There was also no difference in pain six to 12 weeks after surgery (p = 0.8). However, at six to eight months, the cortical screw cohort had worse pain compared to the pedicle screw cohort (p = 0.02). CONCLUSIONS: The cortical screw patients showed a trend towards less peak pain in the short-term (one to three days post-surgery) and more pain in the long-term (six to eight months post-surgery) compared to pedicle screw patients. Both cohorts had a statistically significant reduction in pain levels compared to preoperative pain. More studies are needed to further evaluate postoperative pain, long-term functional outcomes, and fusion rates in patients who undergo cortical screw fixation.

Treatment of Nystagmus in Brainstem Cavernous Malformation with Botulinum Toxin.

We report a long-term eye movement study of a 68-year-old female with pontomedullary junction cavernous malformation whose dysconjugate nystagmus was treated with retrobulbar botulinum toxin A injections. Sequential, bilateral retrobulbar injections of botulinum toxin A were performed. Injections immediately decreased oscillopsia and nystagmus, and improved visual acuities. One to three months following injection, three-dimensional infrared oculography measured a significant 39-100% (P = 0.001) decrease in nystagmus amplitudes at multiple dimensions. This improvement diminished by six months in the right eye but sustained for about one year in the left eye. Over two years, botulinum toxin A injections were performed twice in the left eye and five times in the right eye. Our study supported the safe and effective use of repetitive retrobulbar botulinum toxin A injections in symptomatic nystagmus that failed medical therapy.