Clinical characteristics of benign paroxysmal positional vertigo after traumatic brain injury.

INTRODUCTION: The aim of the present study was to evaluate the characteristics of brain injury and to assess the relationship between them and treatment outcomes in patients with traumatic benign paroxysmal positional vertigo (t-BPPV). MATERIALS AND METHODS: Sixty-three consecutive patients who were diagnosed with BPPV within 2 weeks after head trauma were included. RESULTS: Cerebral concussion, intracranial hemorrhages (ICH), skull fracture without ICH, and hemorrhagic contusion were observed in 68%, 24%, 5%, and 3% of t-BPPV patients, respectively. BPPV with single canal involvement was observed in 52 (83%) patients and that with multiple canal involvement was observed in 11 (17%) patients. The number of treatment sessions was not significantly different according to the cause of head trauma (p = 0.252), type of brain injury (p = 0.308) or location of head trauma (p = 0.287). The number of recurrences was not significantly different according to the cause of head trauma (p = 0.308), type of brain injury (p = 0.536) or location of head trauma (p = 0.138). CONCLUSION: The present study demonstrated that there were no significant differences in treatment sessions until resolution and the mean number of recurrences according to the type of brain injury.

Effect of a differential training paradigm with varying frequencies and amplitudes on adaptation of vestibulo-ocular reflex in mice.

The vestibulo-ocular reflex (VOR) functions to maintain eye stability during head movement, and VOR gain can be dynamically increased or decreased by gain-up or gain-down adaptation. In this study, we investigated the impact of a differential training paradigm with varying frequencies and amplitudes on the level of VOR adaptation in mice. Training for gain-up (out of phase) or gain-down (in phase) VOR adaptation was applied for 60 min using two protocols: (1) oscillation of a drum and turntable with fixed frequency and differing amplitudes (0.5 Hz/2.5°, 0.5 Hz/5° and 0.5 Hz/10°). (2) Oscillation of a drum and turntable with fixed amplitude and a differing frequency (0.25 Hz/5°, 0.5 Hz/5° and 1 Hz/5°). VOR adaptation occurred distinctively in gain-up and gain-down learning. In gain-up VOR adaptation, the learned increase in VOR gain was greatest when trained with the same frequency and amplitude as the test stimulation, and VOR gain decreased after gain-up training with too high a frequency or amplitude. In gain-down VOR adaptation, the decrease in VOR gain increased as the training frequency or amplitude increased. These results suggest that different mechanisms are, at least in part, involved in gain-up and gain-down VOR adaptation.

Direction-changing spontaneous nystagmus in patients with dizziness.

PURPOSE: The present study aimed to investigate the clinical features of patients with direction-changing spontaneous nystagmus (DCSN) and gain insight into its underlying mechanisms. METHODS: Medical records and vestibular function test results collected in our dizziness clinic between February 2013 and February 2020 were retrospectively reviewed. Spontaneous nystagmus was recorded while sitting upright using videonystagmography for 2 min to confirm the spontaneous changes in nystagmus direction. Causative disease diagnoses were based on the patients' clinical history, audiometry results, vestibular function tests, and imaging studies. RESULTS: Of 4786 patients, DCSN was observed in 41 (0.86%). Causative disease diagnoses included vestibular neuritis (n = 9), lateral semicircular canal cupulopathy (n = 9), cerebellopontine angle tumor (n = 8), vestibular paroxysmia (n = 2), vestibular migraine (n = 2), vestibular nucleus infarction (n = 1), sudden sensorineural hearing loss with vertigo (n = 2), Meniere's disease (n = 2), Ramsay Hunt syndrome (n = 1), labyrinthine fistula due to middle ear cholesteatoma (n = 1), lateral semicircular canal dysplasia (n = 1), post tympanomastoidectomy dizziness (n = 1), and head trauma (n = 2). CONCLUSIONS: Although the periodicity of DCSN could not be determined because of insufficiently long observation times, it was observed in various central and peripheral vestibulopathies. Careful examination of spontaneous nystagmus over a sufficient period may ensure the detection of DCSN when evaluating dizziness.

When Bigger Is Not Greener: Ensuring the Sustainability of Power-to-Gas Hydrogen on a National Scale.

As the prices of photovoltaics and wind turbines continue to decrease, more renewable electricity-generating capacity is installed globally. While this is considered an integral part of a sustainable energy future by many nations, it also poses a significant strain on current electricity grids due to the inherent output variability of renewable electricity. This work addresses the challenge of renewable electricity surplus (RES) utilization with target-scaling of centralized power-to-gas (PtG) hydrogen production. Using the Republic of Korea as a case study, due to its ambitious plan of 2030 green hydrogen production capacity of 0.97 million tons year-1, we combine predictions of future, season-averaged RES with a detailed conceptual process simulation for green H2 production via polymer electrolyte membrane (PEM) electrolysis combined with a desalination plant in six distinct scale cases (0.5-8.5 GW). It is demonstrated that at scales of 0.5 to 1.75 GW the RES is optimally utilized, and PtG hydrogen can therefore outperform conventional hydrogen production both environmentally (650-2210 Mton CO2 not emitted per year) and economically (16-30% levelized cost reduction). Beyond these scales, the PtG benefits sharply drop, and thus it is answered how much of the planned green hydrogen target can realistically be "green" if produced domestically on an industrial scale.

Adaptation of Optokinetic Reflex by Training with Different Frequency and Amplitude.

BACKGROUND: Although the occurrence of optokinetic reflex (OKR) adaptation after OKR training is well established, the dynamic properties of OKR adaptation has not been fully studied. This study aimed to examine the difference in the amount of OKR adaptation according to OKR training protocols which have different frequency or amplitude of drum oscillation. METHODS: Using C57BL/6N male mice, we induced OKR adaptation by 3 different categories of learning paradigm as follows: (1) Optokinetic drum oscillation for 60 min with same amplitude and different frequency. (2) Optokinetic drum oscillation for 60 min with same frequency and different amplitude. (3) Training with serial combination of different frequency or amplitude. RESULTS: The results show that the amount of OKR adaptation was greater after OKR training with lower frequency or amplitude than that with higher frequency or amplitude. CONCLUSIONS: This finding may suggest that the retinal slip signal with lower-velocity OKR stimulation serves as more precise instructive signal for learning, leading to induction of more efficient training effect. Another interesting finding was that the OKR gain increase tended to be greater after training composed of sequential combination of decreasing frequency or amplitude than that composed of sequential combination of increasing frequency or amplitude. Furthermore, the OKR training with high frequency or amplitude eliminated a part of learning effects which have already formed by previous training. We postulate that the stimulation during training with high frequency or amplitude may implement a disturbing instruction for OKR learning when it is conducted in mice with increased OKR gain after previous OKR training.

Nystagmus in Ramsay Hunt syndrome with or without dizziness.

BACKGROUND: The presence of dizziness has been reported as a negative prognostic factor for recovery of facial palsy in Ramsay Hunt syndrome (RHS). The aim of this study was to investigate the incidence and patterns of nystagmus in RHS patients without dizziness, and discuss possible mechanisms. We also compared the severity and prognosis of facial palsy between RHS patients with and without dizziness. METHODS: From January 2014 to January 2019, 36 patients diagnosed with RHS (27 with dizziness and 9 without dizziness) were included. Patterns of nystagmus were examined and categorized using video-nystagmography. House-Brackmann(HB) grade of facial palsy was compared between RHS patients with and without dizziness. RESULTS: Not only RHS patients with dizziness exhibited nystagmus in most cases (96%, 26 of 27) but also as many as 67% (6 of 9) of RHS patients without dizziness exhibited nystagmus, though the intensity was remarkably weak. In both groups of RHS with and without dizziness, direction-fixed nystagmus and direction-changing positional nystagmus were observed. Initial HB grade and recovery of facial palsy after treatment were not significantly different between RHS with and without dizziness. CONCLUSION: Various patterns of nystagmus including direction-fixed and positional direction-changing nystagmus were observed in RHS patients, and inflammation of the vestibular nerve and inner ear end organs may be responsible for the production of nystagmus in these patients. The results support that the evaluation of vestibular function may be necessary even in RHS patients who do not complain of dizziness or vertigo.

Facial Nerve Hematoma After Penetrating Middle Ear Trauma: A Cause of Delayed Facial Palsy.

ABSTRACT: Penetrating middle ear injury may cause hearing loss, vertigo, or facial nerve injury, although facial nerve paralysis followed by head trauma is a rare condition. In this study, we report a case of a 3-year-old patient with delayed facial palsy on the left side that developed 4 days after an accidental tympanic membrane perforation caused by a cotton-tipped swab. Otoendoscopic examination revealed a perforation in the posterosuperior quadrant of the tympanic membrane. Audiometry revealed no hearing loss on the injured side, and eye movement examination did not reveal spontaneous or positional nystagmus. Pre- and postcontrast T1-weighted magnetic resonance imaging demonstrated high signal intensity along the tympanic portion of the fallopian canal, which suggested that hemorrhage within the facial canal may be a cause of delayed facial palsy. It can be assumed that traumatic injury at the dehiscent facial nerve in the tympanic portion caused hematoma within the fallopian canal, resulting in delayed facial nerve palsy.

Bone mineral density and serum 25-hydroxyvitamin D in subtypes of idiopathic benign paroxysmal positional vertigo.

Although the etiology of benign paroxysmal positional vertigo (BPPV) is idiopathic in most cases, the association of osteoporosis or vitamin D deficiency with BPPV has attracted much interest recently. While it is generally accepted that osteoporosis or vitamin D deficiency is related to the occurrence and/or recurrence of BPPV, the difference in serum vitamin D level and bone mineral density (BMD) among different subtypes of BPPV has not been investigated. We aimed to compare T-score of BMD score and serum 25-hydroxyvitamin D level among idiopathic BPPV patients with a different subtype. This study included 117 consecutive patients with idiopathic BPPV (26 men and 91 women; mean age, 55 ±â€¯11 years; age range, 25 to 78 years) who underwent blood sampling for serum 25-hydroxyvitamin D level measurement and bone mineral densitometry of the anterior-posterior lumbar spine and femur between April 2018 and February 2019. Among 117 patients, 49 were diagnosed with posterior semicircular canal (PSCC) BPPV, 24 were diagnosed with lateral semicircular canal (LSCC) canalolithiasis, and 44 were diagnosed with LSCC cupulolithiasis. The mean T-score of BMD was -1.5 ±â€¯0.9 in PSCC BPPV, -1.5 ±â€¯1.3 in LSCC canalolithiasis, and -1.5 ±â€¯1.1 in LSCC cupulolithiasis, which was not significantly different (p = 0.998, One-way ANOVA test). The mean level of 25-hydroxyvitamin D was 22.5 ±â€¯10.6 ng/ml in PSCC BPPV, 26.8 ±â€¯16.0 ng/ml in LSCC canalolithiasis, and 25.4 ±â€¯9.6 ng/ml in LSCC cupulolithiasis, which was not significantly different (p = 0.262, One-way ANOVA test). The proportion of osteoporosis/osteopenia or vitamin D deficiency/insufficiency did not show significant difference among idiopathic BPPV patients with different subtypes, and findings of this study indicate that either serum level of vitamin D or T-score of BMD is not a distinguishable characteristic among different subtypes of BPPV.

Atypical clinical manifestations of herpes zoster oticus: diagnostic usefulness of magnetic resonance imaging.

Typical symptoms of Ramsay Hunt syndrome (RHS) consist of painful vesicular eruptions in the external ear, unilateral facial palsy, and/or vestibulocochlear deficit. When RHS patients show atypical clinical manifestations, correct diagnosis can be delayed, and ideal treatment timing for antiviral therapy may be missed. The aim of this study is to describe RHS patients with atypical clinical manifestations and evaluate the usefulness of magnetic resonance imaging (MRI) for early differential diagnosis. We retrospectively reviewed the clinical data and investigated the findings of internal auditory canal (IAC) MRI of seven patients diagnosed with RHS presenting "atypical" clinical manifestations between January 2013 and December 2016. "Typical" symptoms of RHS consist of herpetic vesicular eruption and facial palsy with or without vestibulocochlear deficit. Regardless of symptomatic presentations, IAC MRI demonstrated post-contrast enhancement of cranial nerve (CN) VII, CN VIII, and IAC dura in patients with atypical clinical manifestations. In cases with multiple lower CN palsy, enhancement along the involved nerve was observed on IAC MRI. When RHS was complicated by acute parotiditis, diffuse enhancement of the parotid gland was demonstrated. The present study shows that in IAC MRI of RHS patients with atypical clinical manifestations, post-contrast enhancement was not confined to the facial nerve but also observed in CN VIII and IAC dura regardless of the symptoms, which may facilitate early diagnosis of RHS.

Is the modified cupulolith repositioning maneuver effective for treatment of persistent geotropic direction-changing positional nystagmus?

OBJECTIVE: Clinicians sometimes see patients with relatively persistent geotropic direction-changing positional nystagmus (DCPN) as a variant of lateral semicircular canal-benign paroxysmal positional vertigo (LSCC-BPPV). Recently, the concept of a "light cupula" in the lateral semicircular canal, exhibiting persistent geotropic DCPN, has been introduced. However, the underlying pathogenesis of light cupula is not known. We investigated the efficacy of a modified cupulopathy repositioning maneuver (mCuRM), designed to reduce light debris attached to the cupula in patients with persistent geotropic DCPN. STUDY DESIGN: Retrospective cohort study. METHODS: Participants included 65 patients with a persistent geotropic DCPN: 35 underwent treatment (mCuRM group), and 30 were followed-up but received no treatment (No CuRM group). We compared the therapeutic and survival rate of persistent geotropic DCPN between two groups. RESULTS: On Day 1, the persistent geotropic DCPN did not resolve in either group. On the first and second follow-up days, persistent geotropic DCPN was observed in 28 (80%) and 21 (60%) of patients, respectively, in the mCuRM group, and in 28 (93.3%) and 24 (80%) patients, respectively, in the no mCuRM group. The differences between groups were not statistically significant. Furthermore, no between-group differences were found in the time from diagnosis to resolution of nystagmus, or the time from symptom onset to resolution of nystagmus. Kaplan-Meier analysis of the time course of persistent geotropic DCPN resolution from the day of diagnosis and day of symptom onset revealed no significant differences between the groups. CONCLUSION: Our findings indicate that mCuRM had no therapeutic benefit for a persistent geotropic DCPN and suggest that the pathophysiology of persistent geotropic DCPN is less likely to be a light debris attached to the cupula.

Effects of hazard perception training (HPT) on nursing students' risk sensitivity to patient safety and developing safety control confidence.

PURPOSE: This study identifies the effects of hazard perception training (HPT) on nursing students' risk sensitivities and safety control confidence. METHODS: The study uses a nonequivalent control group pre-and post-test design. The participants were 107 senior nursing students, 52 in the experimental group, and 55 in the control group. The experimental group was shown 5 hospital situation pictures to determine hazard sensitivity. Students' risk sensitivity scores and safety control confidence were measured pre-HPT and post-HPT. RESULTS: The experimental group showed significantly higher (on) total risk sensitivity score (t=12.47, p<0.001) and themes, such as fall down (t=19.33, p<0.001), preoperative time out (t=3.18, p<0.001), invasive treatment (t=12.40, p<0.001), and medication (t=10.98, p<0.001). However, the difference for telephone orders was insignificant between the experimental and control groups (t=-0.17, p=0.864). In addition, difference of mean scores for safety control confidence was insignificant between the experimental and the control groups (t=1.10, p=0.275). CONCLUSION: Nursing education should incorporate hazard perception training more often, and educators need to develop education programs to improve nursing students' safety control confidence. Further, a Hazard Perception Training (HPT) that incorporates various kinds of educational methods for students majoring in healthcare fields is needed.

Kaposi's Sarcoma-Associated Herpesvirus (KSHV) Induces the Oncogenic miR-17-92 Cluster and Down-Regulates TGF-ß Signaling.

KSHV is a DNA tumor virus that causes Kaposi's sarcoma. Upon KSHV infection, only a limited number of latent genes are expressed. We know that KSHV infection regulates host gene expression, and hypothesized that latent genes also modulate the expression of host miRNAs. Aberrant miRNA expression contributes to the development of many types of cancer. Array-based miRNA profiling revealed that all six miRNAs of the oncogenic miR-17-92 cluster are up-regulated in KSHV infected endothelial cells. Among candidate KSHV latent genes, we found that vFLIP and vCyclin were shown to activate the miR-17-92 promoter, using luciferase assay and western blot analysis. The miR-17-92 cluster was previously shown to target TGF-ß signaling. We demonstrate that vFLIP and vCyclin induce the expression of the miR-17-92 cluster to strongly inhibit the TGF-ß signaling pathway by down-regulating SMAD2. Moreover, TGF-ß activity and SMAD2 expression were fully restored when antagomirs (inhibitors) of miR-17-92 cluster were transfected into cells expressing either vFLIP or vCyclin. In addition, we utilized viral genetics to produce vFLIP or vCyclin knock-out viruses, and studied the effects in infected TIVE cells. Infection with wildtype KSHV abolished expression of SMAD2 protein in these endothelial cells. While single-knockout mutants still showed a marked reduction in SMAD2 expression, TIVE cells infected by a double-knockout mutant virus were fully restored for SMAD2 expression, compared to non-infected TIVE cells. Expression of either vFLIP or vCycIin was sufficient to downregulate SMAD2. In summary, our data demonstrate that vFLIP and vCyclin induce the oncogenic miR-17-92 cluster in endothelial cells and thereby interfere with the TGF-ß signaling pathway. Manipulation of the TGF-ß pathway via host miRNAs represents a novel mechanism that may be important for KSHV tumorigenesis and angiogenesis, a hallmark of KS.

Repair of the Posterior Third of the Meniscus During Meniscus Allograft Transplantation: Conventional Inside-Out Repair Versus FasT-Fix All-Inside Repair.

PURPOSE: To compare conventional inside-out (IO) repair and all-inside (AI) repair for the posterior third of the meniscus during meniscus allograft transplantation (MAT). METHODS: Among the 64 enrolled patients, 31 patients underwent MAT with conventional IO repair, and 33 patients underwent MAT with AI repair using the FasT-Fix instrument for the posterior third of the meniscus allograft. All of the patients were retrospectively evaluated through clinical assessment at the last follow-up (54.3 months in the IO group and 55.4 months in the AI group) and through magnetic resonance imaging assessment for meniscal extrusion at 1 year postoperatively. Thirty patients (15 in each group) were evaluated through second-look arthroscopy at 1 year postoperatively. RESULTS: There was no significant difference in the mean Lysholm score (91.3 in the IO group and 92.3 in the AI group; P = .358) or the mean Tegner activity scale (7.1 in each group; P = .885) between the 2 groups. There was no significant difference in the mean meniscal extrusion (2.6 mm in the IO group and 2.8 mm in the AI group; P = .454), relative percentage of extrusion value (25.6% in the IO group and 24.7% in the AI group; P = .721), or meniscal healing on second-look arthroscopy (P = .796) between the 2 groups. The difference in operative time between the 2 groups was found to be statistically significant (169.9 minutes in the IO group and 123.3 minutes in the AI group; P < .001). CONCLUSIONS: Our comparative study on the different techniques for posterior repair of meniscus allograft suggested that AI posterior repair using FasT-Fix could be an alternative method to conventional IO repair as it gives a similar postoperative result and requires a shorter operative time.

Clinical manifestations in patients with herpes zoster oticus.

Patients with herpes zoster oticus (HZO) may exhibit diverse symptoms regarding cochleovestibular dysfunction. This study investigated the clinical manifestations of HZO by comparing symptoms associated with dysfunctions of the 7th and 8th cranial nerves (CN VII and VIII, respectively). This study is a retrospective case series. Eighty-one patients with HZO who had dysfunction of CN VII or VIII were included in this study. Electroneuronography (ENoG) values were compared among patient groups with facial weakness. Patients with ipsilateral facial weakness (62 of 81) were more common than those without. Among 81 patients, those with facial weakness, hearing loss, and vertigo were most common, and only 1 patient had vertigo without hearing loss or facial weakness. Most patients with vertigo also had hearing loss (28 of 30), and patients without hearing loss did not have vertigo (19 of 21). While patients with vertigo had worse ENoG values than those without vertigo, ENoG values were not significantly different between patients with and without hearing loss. In conclusion, various clinical manifestations of CN VII and VIII dysfunction are possible in patients with HZO. Patients with vertigo had worse ENoG values than those without, which may indicate that vertigo reflects more severe facial nerve degeneration in HZO patients with facial weakness.

Lateralization of horizontal semicircular canal canalolithiasis and cupulopathy using bow and lean test and head-roll test.

Accurate lateralization is important to improve treatment outcomes in horizontal semicircular canal (HSCC) benign paroxysmal positional vertigo (BPPV). To determine the involved side in HSCC-BPPV, the intensity of nystagmus has been compared in a head-roll test (HRT) and the direction of nystagmus was evaluated in a bow and lean test (BLT). The aim of this study is to compare the results of a BLT with those of a HRT for lateralization of HSCC-canalolithiasis and cupulopathy (heavy cupula and light cupula), and evaluate treatment outcomes in patients with HSCC-canalolithiasis. We conducted retrospective case reviews in 66 patients with HSCC-canalolithiasis and 63 patients with HSCC-cupulopathy. The affected side was identified as the direction of bowing nystagmus on BLT in 55 % (36 of 66) of patients with canalolithiasis, which was concordant with the HRT result in 67 % (24 of 36) of cases (concordant group). Lateralization was determined by comparison of nystagmus intensity during HRT in 30 patients who did not show bowing or leaning nystagmus. The remission rate after the first treatment was 71 % (17 of 24) in the concordant group and 45 % (5 of 11) in the discordant group. Both bowing and leaning nystagmus were observed in all patients with cupulopathy, and the side of the null plane was identified as the affected side. In conclusion, bowing and/or leaning nystagmus were observed in only 55 % of patients with HSCC-canalolithiasis, and the first treatment based on the result of BLT alone was effective in only 45 % of the patients in whom the BLT and HRT were discordant, which may suggest that the usefulness of BLT in lateralizing the HSCC-canalolithiasis may be limited.

Sudden sensorineural hearing loss with positional vertigo: Initial findings of positional nystagmus and hearing outcomes.

OBJECTIVES: To investigate the initial findings of positional nystagmus in patients with sudden sensorineural hearing loss (SSNHL) and positional vertigo, and to compare hearing improvement among patients with different types of positional nystagmus. DESIGN: The characteristics of positional nystagmus upon initial examination were analysed, and the initial mean pure-tone audiometry (PTA) threshold was compared with that at three months after treatment. STUDY SAMPLE: Forty-four SSNHL patients with concomitant positional vertigo were included. RESULTS: Positional nystagmus was classified into five subgroups; persistent geotropic direction-changing positional nystagmus (DCPN) in head-roll test (HRT) and negative Dix-Hallpike test (DHT), persistent apogeotropic DCPN in HRT and negative DHT, positive DHT and negative HRT, persistent geotropic DCPN in HRT and positive DHT, and persistent apogeotropic DCPN in HRT and positive DHT. PTA threshold improvement was significantly greater in SSNHL patients with negative DHT than with positive DHT (p = 0.027). CONCLUSIONS: When geotropic DCPN was elicited by HRT, the nystagmus was persistent, which suggests that alteration of specific gravity of the endolymph, rather than the lateral canal canalolithiasis, may be a cause of this characteristic positional nystagmus. Positive DTH may be a prognostic factor for worse hearing recovery among patients with SSNHL and positional vertigo.

Fibrosis Within the Tympanic Membrane.

A primary mass lesion arising from the tympanic membrane is extremely rare. The authors report a patient of extensive fibrosis within the tympanic membrane in a 65-year-old woman who did not have a history of ear infection. The patient complained of slow progressing hearing loss on the left side without otorrhea or otalgia. Otoscopic examination showed a thick tympanic membrane with whitish mass-like bulge, and pure-tone audiometry revealed conductive hearing loss. The lesion was totally resected, and final findings of a histopathologic examination revealed extensive fibrosis with subsiding inflammation within the tympanic membrane. Fibrosis within the tympanic membrane may present with slow progressing conductive hearing loss and should be considered a possible differential diagnosis of mass lesions in the tympanic membrane.

Robotic surgery for rectal cancer can overcome difficulties associated with pelvic anatomy.

INTRODUCTION: Total mesorectal excision (TME) for rectal cancer can be challenging to perform in the presence of difficult pelvic anatomy. In our previous studies based on open and laparoscopic TME, we found that pelvic MRI-based pelvimetry could well reflect anatomical difficulty of the pelvis and operative time increased in direct proportion to the difficulty. We explored different outcomes of robotic surgery for TME based on classifications of difficult pelvic anatomies to determine whether this method can overcome these challenges. METHODS: We reviewed data from 182 patients who underwent robotic surgery for rectal cancer between January 2008 and August 2010. Patient demographics, pathologic outcomes, pelvimetric results, and operative and postoperative outcomes were assessed. The data were compared between easy, moderate, and difficult groups classified by MRI-based pelvimetry. RESULTS: Comparing the three groups, there was no difference between the groups in terms of operative and pathologic outcomes, including operation time. High BMI, history of preoperative chemoradiotherapy, and lower tumor levels were significantly associated with longer operation time (p < 0.001, p < 0.001, p = 0.009), but the pelvimetric parameter was not. CONCLUSION: There was no difference between the easy, moderate, and difficult groups in terms of surgical outcomes, such as operation time, for robotic rectal surgery. The robot system can provide more comfort during surgery for the surgeon, and may overcome challenges associated with difficult pelvic anatomy.

Light cupula of the horizontal semicircular canal occurring alternately on both sides: a case report.

BACKGROUND: The light cupula is a condition wherein the cupula of the semicircular canal has a lower specific gravity than its surrounding endolymph. It is characterized by a persistent geotropic direction-changing positional nystagmus in the supine head-roll test, and the identification of a null plane with slight head-turning to either side. CASE PRESENTATION: This study describes a case of recurring light cupula that occurred alternately on both sides. At the first episode, a null plane was identified on the right side, which led to the diagnosis of a light cupula on the right side. At the second episode, a null plane was identified on the left side, leading to the diagnosis of a light cupula on the left side. CONCLUSION: This is the first case report of recurring light cupula alternately involving both sides. Although the pathophysiology is not entirely understood yet, the light cupula should be considered as one of causes of recurrent positional vertigo.