Partial Decompression Research Articles

Dewatering Spent Ion-Exchange Resins with Supercritical CO2

ABSTRACT A process for dewatering spent ion exchange resins (gel and porous) used in nuclear power plants by supercritical CO2 (sCO2) is described. The amount of water removed by sCO2 is much higher than that expected from solubility considerations alone. Water from gel-type resins is both dissolved by and emulsified in sCO2. Emulsification also occurs in the absence of solids when water alone is contacted by sCO2. It is not a factor for microporous resins where an additional mechanism, viscous fingering, is involved. It appears that bulk water is emulsifiable but not if it is held in pores. Dewatering via viscous fingering has been previously invoked for matrices such as wood and sludge. The resins can be dewatered and dried with sequential batches of sCO2 at sub-boiling temperatures. The CO2 can then be potentially reused after expansion and separation from the entrained water. Partial decompression of the water-laden sCO2 would lead to cooling, which would drop the water solubility substantially. A reduction of temperature from 90 oC to 65oC reduces the solubility of water in sCO2 by a factor of five. The condensed water could then be separated with a hydrocyclone. The footprint of sCO2 is much smaller than the conventional drying process. The energy costs are also much lower because evaporation of water is avoided.

Petrogenesis and tectonic setting of Early Cretaceous mafic dykes in the North Qinling Orogenic Belt, central China: constraints on the lithospheric lower crust delamination

Late Mesozoic mafic dykes, which are widely developed in the North Qinling Orogenic Belt (NQOB), include abundant geodynamic information. This paper describes the mafic dykes that intrude the Late Jurassic granite in the Dayu and Kuyu areas, and reports important petrological constraints for the late Mesozoic tectonic transition from compression to extension in the NQOB. Three zircon U–Pb results show that the minimum ages of the mafic dykes are 139.8 ± 1.4 Ma, 137.4 ± 1.7 Ma and 133.4 ± 0.9 Ma, indicating that the emplacement age of the Dayu and Kuyu mafic dykes is 140–133 Ma. Petrogeochemical analyses suggest that the mafic dykes belong to the high-K calc-alkaline shoshonite series with low SiO2 (46.93–56.73 wt%), MgO (1.88–9.10 wt%) and TiO2 (1.17–1.82 wt%), and high Al2O3 (13.98–17.46 wt%), TFe2O3 (7.81–10.92 wt%) and K2O (1.28–4.78 wt%). The mafic dykes are enriched in large ion lithophile elements (e.g. Rb, Ba, K, La, Sr) and depleted in high-field-strength elements (e.g. Nb, Ta, Zr, Ti). These samples have the right-sloping chondrite-normalised rare earth element patterns, which suggest light rare earth element enrichment and heavy rare earth elements depletion with no obvious Eu anomalies (δEu = 0.94–1.11). The I Sr, ε Nd(t), ε Hf (t) and T DM2(crust) values are 0.7056–0.7060, −10.60 to −5.98, −14.1 to −2.8, and 1382.4 ± 25.1 to 2081.9 ± 47.6 Ma, respectively. Both elemental and isotopic geochemistry show that the formation of Dayu and Kuyu mafic dykes is due to the partial decompression melting of previously enriched lithospheric mantle during a delamination process. The mafic dykes have undergone fractionation crystallisation of Mg–Fe phase minerals during magma ascent, accompanied by some crustal contamination. Combined with the regional tectonic setting, we suggested that the NQOB experienced intra-continental extension during the Early Cretaceous. KEY POINTS Early Cretaceous (140–133 Ma) mafic dykes have been discovered in the middle part of the North Qinling Orogenic Belt. The remote effect of the Paleo-Pacific Plate subduction has reached the middle of the North Qinling Orogenic Belt. The North Qinling Orogenic Belt entered the extensional stage in the Early Cretaceous (140–133 Ma).

Facial Palsy Secondary to Cholesteatoma: A Case-Series of 14 Patients

To evaluate patients with middle ear cholesteatoma presenting with facial palsy (FP). A total of 14 subjects (10 males and 4 females), with a mean age of 42.5 years, were included in our study. The majority of patients presented with incomplete FP (House-Brackmann HB II-IV, 11 cases) and the remaining 3 patients had complete facial paralysis (HB V-VI). A canal wall down mastoidectomy was performed in all the patients, followed by partial facial nerve decompression. At the one-year follow-up, eleven (78.5%) patients demonstrated satisfactory recovery to HB I-II. Facial function recovered to HB grade I-II in 9 (100%) patients who were surgically treated within one month, and in 2 (40%) patients who underwent surgery after one month. The tympanic segment of facial nerve was the most common site of involvement (8 patients). The multiple regression analysis showed that a higher preoperative HB grade combined with a gradual than sudden onset of FP more likely resulted in worse postoperative HB grade. Early surgical removal of cholesteatoma associated with FP is more likely to result in good facial nerve recovery (78.5% of cases), when it is performed within one month from the onset of FP. According to the literature, the tympanic segment of the facial nerve was more frequently damaged (77.7%), followed by the mastoid segment (22.9%), labyrinthine segment (11.1%), and geniculate ganglion (11.1%). Labyrinthine fistula, mainly of the lateral semicircular canal, can be expected in cases of facial nerve dehiscence. The canal wall down mastoidectomy combined with partial decompression surgery was the most preferred surgical treatment for the FP secondary to cholesteatoma.

Residual anterior cord compression after laminoplasty for cervical spondylotic myelopathy: evaluation of risk factors according to the most severely stenotic vertebral segment.

Residual anterior spinal cord compression (RASCC) after cervical laminoplasty, which has been confirmed on postoperative MRI, is reportedly associated with poor clinical outcomes. To date, only a few studies have described the risk factors associated with RASCC. The aim of this study was to identify the factors that can predict the occurrence of RASCC after laminoplasty for cervical spondylotic myelopathy (CSM), focusing on the location of the most stenotic segment. In this retrospective, single-center study, 120 patients who underwent C3-7 laminoplasty for multilevel CSM were included. Different techniques were used for C3 decompression, i.e., partial (dome-laminotomy) or complete (laminoplasty/laminectomy) decompression. RASCC was diagnosed using MRI conducted 3 weeks postoperatively. The patients were divided into two groups according to the segment with the most severe stenosis (Seg-MSS; C3-4 vs C4-7). Demographics, radiological data, and C3 decompression technique were compared between the two groups. Furthermore, intergroup comparisons were performed based on Seg-MSS. A logistic regression model was constructed to identify the factors predicting RASCC after patient stratification according to Seg-MSS. Forty patients (33.3%) had RASCC. The patients with Seg-MSS at C3-4 (51.3%) had a significantly higher incidence of RASCC (p = 0.003) than those with Seg-MSS at C4-7 (24.7%). Logistic regression analysis showed that in patients with Seg-MSS at C3-4, C3 partial decompression demonstrated a greater association with RASCC as opposed to complete decompression. Conversely, in patients with Seg-MSS at C4-7, kyphotic segmental lordotic angle was associated with an increased risk of RASCC. The risk factors for RASCC differed depending on the location of the most stenotic segment (C3-4 vs C4-7). If there is segmental kyphosis at the most stenotic segment at C4-7, anterior decompression and fusion should be considered. If C3-4 is the most stenotic segment, anterior surgery is also recommended, but alternatively, one can choose laminoplasty with complete C3 laminectomy and resection of the C2-3 ligamentum flavum.

New constraints on the tectonometamorphic evolution of the Erzgebirge orogenic wedge (Saxothuringian Domain, Bohemian Massif)

AbstractIn contrast to well‐documented (U)HP rocks of the Erzgebirge crystalline complex (Saxothuringian Domain, Bohemian Massif), the surrounding medium‐ to low‐grade metasediments are scarcely studied, although they provide an important link between deep subduction and mid‐crustal processes. To constrain the Variscan evolution from continental subduction to orogenic wedge, the transition from the low‐grade phyllites to the footwall medium‐grade micaschists was investigated. We used thermodynamic modelling to constrain the P‐T conditions of four deformation fabrics (D1–D4) identified by the structural analysis. The studied area was first affected by the M1‐D1 event characterized by HP‐LT minerals (garnet, chloritoid, phengite, paragonite, and rutile) defining the S1 foliation. The calculated peak P‐T conditions for M1 increase from 13 kbar and 520°C in phyllites to 25 kbar and 560°C in micaschists. The corresponding apparent geothermal gradient 6–11°C/km is typical for a subduction environment. The M2‐D2 event corresponds to deformation and metamorphic overprint of the previous fabric during partial decompression. The M3‐D3 event is mainly developed in micaschists, and the M3 overprint intensifies towards the footwall. It is accompanied by a subhorizontal S3 cleavage characterized by MP‐MT assemblage containing biotite, staurolite and ilmenite. The inferred peak P‐T conditions for M3 are 5–9 kbar and 595°C representing a barrovian‐type geothermal gradient from 17–30°C/km. Finally, all metamorphic fabrics were heterogeneously affected by the low‐grade M4‐D4 upright folding. The D1‐D2 events are interpreted to record the growth and evolution of the Saxothuringian orogenic wedge while its present‐day architecture resulted from significant vertical shortening D3 associated with barrovian type M3‐metamorphism. This stage corresponds to the ductile thinning of the wedge. A new model is proposed, in which the Erzgebirge part of the Saxothuringian Domain reveals a spectacular example of active margin evolution characterized by (i) formation of accretionary prism, (ii) building of the orogenic wedge by accretion of subducted continental crust, and (iii) its extensional collapse.

LGG-20. CLINICAL FEATURES AND TREATMENT RESULTS FOR PEDIATRIC OPTICO-HYPOTHALAMIC ASTROCYTOMA

Current consensus for the treatment of optico-hypothalamic astrocytoma (OHA) is a chemotherapy-first policy, limiting the role of surgery for histopathological diagnosis and partial decompression. However, a subgroup of OHA patients show resistance to chemotherapy and have a worse prognosis. In this study, we retrospectively analyzed our clinical experiences of the treatment of patients with OHA in two university hospitals. We have extracted and analyzed the medical charts of 15 pediatric OHA patients treated in two university hospitals since 1990. NF-1-associated OHA patients were excluded. Patient ages ranged from 10 months to 21 years (median 7 years). Out of 15 cases, 12 patients had a tumor larger than 3 cm and classified as Dodge 3. The final histopathological diagnosis was pilocytic astrocytoma in 13 cases. Three patients with tumors classified as Dodge 1 or 2 show good prognosis only by biopsy or partial resection. However, regarding Dodge 3 tumor, patient prognosis is worse regardless of chemotherapy and radiotherapy. After the initial surgery, chemotherapy was administered in 11 cases and radiotherapy in 5 cases. Multiple surgeries are needed for tumor control in 7 patients. Four patients died of tumor progression or treatment-associated complications. When the initial tumor is large enough to cause neurological deterioration, a chemotherapeutic tumor suppressive effect might be limited in a subset of large OHA cases. Therefore, it is important to consider the proper timing of safe surgical decompression in the early phase when a large tumor does not respond to chemotherapy.

Mechanisms of Partial Melting of Metasomatized Mantle Ultramafic Rocks beneath Avacha Volcano, Kamchatka, and the Growth of Minerals from a Gas Phase in Fractures

Data on xenoliths carried by lavas of Avacha volcano and ejected during eruptions are used in discussing the partial melting of metasomatized rocks of the lithospheric mantle (which were tectonically reformed by seismic events beneath the frontal zone of Avacha volcano) and the associated growth of minerals from a gas phase in open fractures above the magma chamber feeding the volcano. Based on a comprehensive study of representative mantle xenoliths from explosions of the volcano, we developed and numerically studied a mathematical model of convective heat and mass transfer in the permeable zone above the feeding magma chamber. The model enables analysis of the area of active seismic destruction of rocks at depths of 30–70 km beneath Avacha volcano. This analysis involves (1) current qualitative genetic hypotheses concerning the nature of the identified textural and structural relationships between the xenoliths and lavas transporting them, (2) data on the composition of mineral-hosted fluid and melt inclusions, (3) estimated homogenization temperatures of the inclusions, and (4) hypothetical melting mechanisms of metasomatized ultramafics and the associated growth mechanism of minerals in open fractures. It is demonstrated that fractured porous seismogenic regions above magma chambers are coupled with a set of convective processes of fluid-mediated heterophase heat and mass transfer in the lithosphere: infiltration metasomatism at the spinel depth facies and the sublimation and condensation of major components from a gas phase. It is hypothesized that local partial decompression melting of highly heated ultramafic and mafic rocks may be followed by major seismic events. It is shown that spinel-facies infiltration metasomatism in fractured mantle rocks may be associated with the growth of crystal crusts and clusters of clinopyroxene and amphibole from a gas phase in open fractures. There are two paths by which decompression partial melting takes place: (1) the melting of spinel aggregates with the host crystals of “metasomatic” orthopyroxene, which replaced olivine in harzburgites, and (2) the development of clinopyroxene, amphibole, and relict orthopyroxene vein fillings. To test these hypotheses, physical experiments were conducted with the use of convective heating of samples of natural xenoliths. The experiments were carried out in a flow-through reactor capable of reproducing the partial melting phenomena and in an electron gun with a power unit for a welding system with a dense electron beam. The latter experiments simulated the sublimation and deposition of major components from a gas phase over the solidus boundary for all petrographic types of mantle ultramafic rocks. Neither structural nor mineralogical indications of the infiltration of magmatic fluid were detected in the experiments, and no traces of diffusion–reaction zoning of the “melt–rock” type were found in the xenoliths.

Clinical presentation and outcome of patients with optic pathway gliomas: A series of twenty patients

Background: Optic pathway gliomas (OPGs) are rare neoplasms where the management strategy is still evolving. The purpose of this study is to present our experience of twenty cases of OPGs with an intent to add to the general fund of knowledge. Materials and Methods: Retrospective chart review of patients with OPGs surgically managed in a single tertiary centre over a period of 5 years. Variables analysed include Age at diagnosis, sex, clinical manifestations, neurofibromatosis (NF1) status, tumour location, treatment modality, symptomatic progression, and complications. Results: Of the 20 patients with OPG in the study with a mean age of 12.8 years, four patients had NF1 and 16 had sporadic OPG. Dimness of vision (80%) and headache (55%) were the most common presenting symptoms. Majority of the tumours were chiasmatic (40%) in location and vision was affected bilaterally. Subtotal resection could be achieved in 12 (60%) partial decompression in 4 (30%) and gross total resection in 2 (10%). Four patients required additional shunt surgery for hydrocephalus. Postoperative radiotherapy was administered to thirteen patients and only one patient received chemotherapy. At the end of a mean follow up period of 44 months tumour recurrence was noticed in 11/20 (55%) patients. Vision improved in none, remained stable in fifteen and deteriorated in five. Three patients (15%) succumbed to tumour regrowth in the follow up period. Conclusions: OPGs are uncommon tumours with unpredictable outcome. Visual deficits are often irreversible and progressive. Curative resection is difficult and adjuvant therapy has variable response. Overall survival rates are good but progression free and survival rates are suboptimal.

3003 A Curious Case of Metastatic Pancreatobiliary Adenocarcinoma With Normal Serological Markers

INTRODUCTION: Liver function tests (LFTs) are used to screen for, exclude, characterize, and monitor hepatopancreatobiliary (HPB) pathologies. However, the utility of LFTs vary widely based on context, and reliance on laboratory tests in place of clinical judgement is a common pitfall for physicians. Here, we describe a case of significant HPB pathology without LFT abnormalities, and use it as a lens to reexamine the utilization of LFTs in clinical practice. CASE DESCRIPTION/METHODS: A 72 year old male with a history of hypertension and hyperlipidemia was admitted to the hospital for two weeks of right upper quadrant (RUQ) abdominal pain without associated factors. Physical exam was notable for a soft, mildly tender, palpable mass in the RUQ extending lateral to the umbilicus. Initial laboratory evaluation—including LFTs, CBC, BMP, and lipase—was normal. However, contrast-enhanced, abdominal CT demonstrated gallbladder distension (17 cm) with dilatation of the intrahepatic, extrahepatic, and pancreatic ducts. MRCP revealed widespread nodularities concerning for metastasis; follow-up ERCP revealed copious bile in the stomach and duodenum but cannulation attempts failed due to scarring in the major papilla area leaving no obvious papillary orifice. The patient was presumed to have a biliary-small bowel fistula allowing for bile drainage. The porta hepatis region contained several malignant-appearing lymph nodes which were biopsied via fine needle aspiration, revealing metastatic adenocarcinoma favoring pancreatobiliary origin. Due to the presumed fistula, he did not need further decompression, and was discharged with oncology follow up. DISCUSSION: This patient's case presents an opportunity to examine the use of LFTs in clinical practice and why they may fail to identify relevant pathology. Two hypotheses provide explanations, the first based on Courvoisier's law which states that a non-tender, palpably enlarged gallbladder is unlikely to be due to gallstones. Unlike the acute nature of choledocholithiasis, slowly progressive malignant obstructions can gradually increase biliary pressures, allowing for the pliable gallbladder to distend without precipitating liver failure or elevating LFTs. Secondly, the fistula may have provided partial decompression, keeping biliary pressures high enough to cause gallbladder distension without elevating LFTs. Thus, distal biliary obstruction should be suspected in patients with palpable gallbladder distension, and LFTs may be normal even with significant HPB pathology.

Analysis of O-Ring Seal Failure under Static Conditions and Determination of End-of-Lifetime Criterion.

Determining a suitable and reliable end-of-lifetime criterion for O-ring seals is an important issue for long-term seal applications. Therefore, seal failure of ethylene propylene diene rubber (EPDM) and hydrogenated nitrile butadiene rubber (HNBR) O-rings aged in the compressed state at 125 °C and at 150 °C for up to 1.5 years was analyzed and investigated under static conditions, using both non-lubricated and lubricated seals. Changes of the material properties were analyzed with dynamic-mechanical analysis and permeability experiments. Indenter modulus measurements were used to investigate DLO effects. It became clear that O-rings can remain leak-tight under static conditions even when material properties have already degraded considerably, especially when adhesion effects are encountered. As a feasible and reliable end-of-lifetime criterion for O-ring seals under static conditions should include a safety margin for slight dimensional changes, a modified leakage test involving a small and rapid partial decompression of the seal was introduced that enabled determining a more realistic but still conservative end-of-lifetime criterion for an EPDM seal.

Deep Lateral Wall Partial Rim-Sparing Orbital Decompression for Treatment of Thyroid-Related Orbitopathy

Deep Lateral Wall Partial Rim-Sparing Orbital Decompression for Treatment of Thyroid-Related Orbitopathy

Factors Influencing Survival of Children with Atypical Teratoid/Rhabdoid Tumors: A Single-Institute Experience in a Developing Country

We evaluated the factors influencing overall survival (OS) and event-free survival (EFS) in children with atypical teratoid/rhabdoid tumors (ATRTs). We performed a retrospective study of children aged <16 years and tumor histological diagnosis of ATRT. Univariate and multivariate analyses were performed to determine the effect of individual and interdependent variables and survival. A total of 34 children had undergone surgery, with a male/female ratio of 1.8:1. On univariate analysis, the factors with statistically significant influence on OS and EFS were the extent of resection (P= 0.012 and P=0.015, respectively), adjuvant therapy (P ≤ 0.001 and P= 0.001, respectively), and rhabdoid cell percentage (P= 0.004 and P= 0.005, respectively). On survival analysis, the median OS and EFS were better for those who had completed adjuvant therapy versus those who had not received adjuvant therapy (OS, 22.7 months vs. 3.5 months; EFS, 10.9 months vs. 3.5 months), those who had undergone gross total resection versus those who had undergone partial decompression (OS, 10.9 months vs. 2 months; EFS, 8.9 months vs. 2.5 months), and those with <50% rhabdoid cells in the biopsy specimen versus those with >50% rhabdoid cells (OS, 10.9 months vs. 3.7 months; EFS, 8.9 months vs. 3.5 months). On multivariate analysis, only the extent of resection and adjuvant therapy status had a significant influence on OS and EFS. Achieving gross total resection should be the aim of surgery, depending on the tumor location, and these children should undergo upfront adjuvant treatment.

Multilevel techniques for compression and reduction of scientific data—the univariate case

We present a multilevel technique for the compression and reduction of univariate data and give an optimal complexity algorithm for its implementation. A hierarchical scheme offers the flexibility to produce multiple levels of partial decompression of the data so that each user can work with a reduced representation that requires minimal storage whilst achieving the required level of tolerance. The algorithm is applied to the case of turbulence modelling in which the datasets are traditionally not only extremely large but inherently non-smooth and, as such, rather resistant to compression. We decompress the data for a range of relative errors, carry out the usual analysis procedures for turbulent data, and compare the results of the analysis on the reduced datasets to the results that would be obtained on the full dataset. The results obtained demonstrate the promise of multilevel compression techniques for the reduction of data arising from large scale simulations of complex phenomena such as turbulence modelling.

Osteochondroma Presenting as a Calcified Mass in the Sellar Region and Review of the Literature.

Objective Osteochondroma (OC) is the most common benign bone neoplasm. It infrequently occurs in the cranial cavity as a calcified lesion and very rarely presents in the sellar region. The present study summarizes the knowledge about OCs of the sellar region. Methods We searched the literature search for the clinical appearance of OCs and other calcified pathologies occurring in the sellar region. Results A total of 21 English-language articles published from 1961 to 2015 documented cases of calcified lesions in the sellar region including cerebral aneurysm, chondroid chordoma, chondroma, craniopharyngioma, OC, odontome, osteoma, pituitary adenoma, pituitary stone, Rathke cleft cyst, retinoblastoma, schwannoma, and xanthogranuloma. Among them, six were OC cases: three in the parasellar region and three in the sellar-suprasellar region. Patients with sellar-suprasellar OCs presented with visual loss and hypopituitarism; patients with parasellar OCs did not show these symptoms. OCs appeared as irregular and multilobulated calcifications on X-ray and computed tomography. On magnetic resonance imaging, OCs showed variable intensity on T1-weighted sequences and consistently heterogenous intensity on T2. Four patients underwent transcranial tumor resection, and the transsphenoidal route was selected for one. Five of the six resulted in a partial resection or internal decompression with a satisfactory outcome. Conclusions Calcified tumors occurring in the sellar region may be OCs, especially if they appear as irregular multilobulated calcification.

Outcome after Surgery of Lumbar Spinal Stenosis: A Randomized Comparison of Bilateral Laminotomy, Trumpet Laminectomy, and Conventional Laminectomy.

Laminectomy is the traditional operating method for the decompression of spinal canal stenosis. New partial decompression processes have been suggested in the treatment of lumbar stenosis. The benefit of a micro surgical approach is the chance of an extensive bilateral decompression of the spinal canal or foramen at one or numerous levels, through a minimal para-spinal muscular separation. To match the safety and the clinical consequences after a bilateral laminotomy, laminectomy and trumpet laminectomy in patients with lumbar spinal stenosis who were randomized to one of three treatment groups. Prospective study. One hundred twenty consecutive patients with 227 levels of lumbar stenosis without significant herniated discs or instability were randomized to three treatment groups [bilateral laminotomy (Group 1), laminectomy (Group 2), and trumpet laminectomy (Group 3)]. Perioperative parameters and complications were documented. Symptoms and scores, such as a visual analog scale (VAS), Oswestry Disability Index, and patient satisfaction, were assessed preoperatively at 3, 6, and 12 months after surgery. Adequate decompression was achieved in all patients on the basis of surgeon satisfaction. The global complication rate was lowest in patients who had undertaken bilateral laminotomy (Group 1). The minimum follow-up of 12 months was achieved in 100% of patients. Matched with that experience in Group 1, but, with more remaining back and leg pain was found in Group 2, 3.85 ± 0.28 and 1.60 ± 0.44, respectively and 3.24 ± 0.22 and 2.44 ± 0.26 in Group 3, respectively compared with 1.84 ± 0.28 and 1.25 ± 0.12 (Group 1) at the 1-year follow-up assessment (p < 0.05). It was the same for the ODI scores, which reached 14 ± 8% (Group 1), 28 ± 12% (Group 2), and 26 ± 16 after 12 months of surgery (Group 3) (significant, p < 0.01 compared with preoperative scores). Patient satisfaction was higher in Group 1, with 7.5, 20, and 25% of patients displeased (in Groups 1, 2, and 3, respectively; p < 0.01). Bilateral Laminotomy is certified acceptable and harmless in decompression of lumbar stenosis, causing a highly significant decrease of symptoms and disability.

Transmastoid reshaping of the sigmoid sinus: preliminary study of a novel surgical method to quiet pulsatile tinnitus of an unrecognized vascular origin.

OBJECTIVE A dominant sigmoid sinus with focal dehiscence or thinning (DSSD/T) of the overlying bony wall is a commonly encountered, but frequently overlooked, cause of vascular pulsatile tinnitus (VPT). Also, the pathophysiological mechanism of sound perception in patients with VPT remains poorly understood. In the present study, a novel surgical method, termed transmastoid SS-reshaping surgery, was introduced to ameliorate VPT in patients with DSSD/T. The authors reviewed a case series, analyzed the surgical outcomes, and suggested the pathophysiological mechanism of sound perception. The theoretical background underlying VPT improvement after transmastoid SS-reshaping surgery was also explored. METHODS Eight patients with VPT that was considered attributable to DSSD/T underwent transmastoid SS-reshaping surgery between February 2010 and February 2015. The mean postoperative follow-up period was 9.5 months (range 4-13 months). Transmastoid SS-reshaping surgery featured simple mastoidectomy, partial compression of the SS using harvested cortical bone chips, and reinforcement of the bony SS wall with bone cement. Perioperative medical records, imaging results, and audiological findings were comprehensively reviewed. RESULTS In 7 of the 8 patients (87.5%), the VPT abated immediately after surgery. Statistically significant improvements in tinnitus loudness and distress were evident on numeric rating scales. Three patients with preoperative ipsilesional low-frequency hearing loss exhibited postoperative improvements in their low-frequency hearing thresholds. No major postoperative complications were encountered except in the first subject, who experienced increased intracranial pressure postoperatively. This subsided after a revision operation for partial decompression of the SS. CONCLUSIONS Transmastoid SS-reshaping surgery may be a good surgical option in patients with DSSD/T, a previously unrecognized cause of VPT. Redistribution of severely asymmetrical blood flow, reinforcement of the bony SS wall with bone cement to reconstruct a soundproof barrier, and disconnection of a problematic sound conduction route via simple mastoidectomy silence VPT.

Spontaneous leaking craniopharyngioma causing preoperative chemical meningitis.

Spontaneous leaking craniopharyngioma causing preoperative chemical meningitis.

Treatment of mono-segmental thoracic spine tuberculosis with one-stage posterior focus debridement and internal fixation of inter-centrum non-structural bone grafting

Objective To evaluate the clinical efficacy and feasibility of treatment of mono-segmental thoracic spine tuberculosis with one-stage posterior focus debridement and internal fixation of inter-centrum non-structural bone grafting. Methods Retrospective study of patients with mono-segmental thoracic spine tuberculosis who underwent surgery in our hospital from January 2010 to January 2013 was conducted. 27 patients were involved in the study, including 16 male patients and 11 female patients. The age of patients is from 23 to 69 (average age 40.3). 22 patients suffered from combined spinal cord dysfunction. For the classification of ASIA, 2 cases were of Grade B, 8 cases were of Grade C and 12 cases were of Grade D. All patients had obvious bone destruction in thoracic spine shown on CT and MRI before the operation. All patients were given anti-tuberculosis drugs (Isoniazid, Rifampicin, Ethambutol, Streptomycin) for 2-3 weeks, preoperatively. And all patients underwent one-stage posterior focus debridement, and bone particles gained from partial decompression and spina iliaca posterior superior bone particles were planted among the centrum. Pedicle screw fixation was conducted internally. Thoracic vertebra X-ray film and CT were rechecked per 3 months after the operation. Bone grafting fusion and physiological curvature change of thoracic vertebra were evaluated. Results All patients were followed up for 12-24 months with the average time of 21.7±2.3 months. The operating time was 110-190 min (average time 167±35 min) and the bleeding amount during the surgery was 350-700 ml (490±160 ml on the average). The bone grafted in centrum achieved bone fusion with the average fusion time of 6.5±2.4 months. The neurological function was improved for all patients, including 19 cases (Grade 1 improvement) and 3 cases (Grade 2 improvement). The preoperative and postoperative Cobb angles of thoracic vertebra were 47°±11° and 41°±9°, respectively. And it was 43°±10° at the final followup period. Conclusion Based on the standardized treatment of antituberculosis drugs and strong fixation with pedicle screw and rod, one-stage posterior focus debridement and internal fixation of inter-centrum non-structural bone grafting are effective and feasible to treat mono-segmental thoracic spine tuberculosis. Key words: Thoracic vertebrae; Tuberculosis; Internal fixators

The Implications of Limited Decompression and Fusion or Decompression Alone Compared to Full Correction in Adult Deformity Surgery

Introduction Some patients request limited surgery instead of full deformity correction and stabilization because of the perceived lower morbidity, risk, and magnitude of surgery. This study is an attempt to evaluate outcomes in patient who select limited fusion/decompression compared with patients who elect to undergo complete deformity correction/stabilization. Materials and Methods We performed a retrospective review of consecutive adult spinal deformity patients treated over a 6 year period who had minimum 1 year of follow-up in the practice of a single spinal surgeon. Patients with cervical or pathological deformity were excluded. Some patients chose only to undergo partial corrections or decompression alone. We compared demographic data of patients choosing among these three options and additionally compared intraoperative blood loss, length of surgery, and length of stay. We also examined the early and late complication rate as well as the number of subsequent spinal surgeries. We additionally compared perioperative change in quality of life measures (ODI, VAS, and SF36v2). Results A total of 103 patients were identified, out of which 59 patients underwent full correction while 24 underwent partial correction and 20 underwent decompression alone. Full correction was achieved in 54 of the 59 patients (91.5%). Patients choosing full correction were significantly younger than those undergoing less than full correction ( p &lt; 0.0001). Attempted full correction was associated with significantly longer length of stay ( p = 0.016), longer surgical duration ( p &lt; 0.0001), and greater volume of intraoperative blood loss ( p = 0.002). There was no clear relationship between extent of surgery and rate of early complications. Late complication and reoperation rates increased as the extent of the initial surgery increased however these differences were not significant. Only 26.2% of patients provided quality of life data. Those undergoing full correction had greatest improvement in ODI, VAS, SF36v2 physical and mental scores, particularly when full correction was achieved. No statistical differences in quality of life measures were detected although type II error is probable. Conclusion Although full deformity correction is more resource intensive and associated with a higher reoperative rate, our results suggest that achieving full deformity correction may achieve the greatest improvement in quality of life measures. A low response rate on quality of life measure surveys limits the strength of our conclusions.

Base of the skull giant cell tumor: Rare presenting features of a rare tumor

An 18-years old girl presented with progressive diminution of vision and trismus for 3 months. On examination, light perception was absent in the right eye along with decreased vision and lateral ophthalmoplegia in the left eye and Grade 2 trismus. On magnetic resonance image, a large mass, isointense on T1 weighted image with contrast enhancement, hyperintense on T2 weighted image, was seen to be arising from the base of the skull with the surrounding bone and soft tissue destruction. She was initially treated with partial decompression of mass. Histopathological examination showed giant cell tumor. Patient was then treated with radiotherapy. The case is described along with a review of the literature.