Elucidating dynamic anaerobe metabolism with HRMAS 13C NMR and genome-scale modeling.

Anaerobic microbial metabolism drives critical functions within global ecosystems, host-microbiota interactions, and industrial applications, yet remains ill-defined. Here we advance a versatile approach to elaborate cellular metabolism in obligate anaerobes using the pathogen Clostridioides difficile, an amino acid and carbohydrate-fermenting Clostridia. High-resolution magic angle spinning nuclear magnetic resonance (NMR) spectroscopy of C. difficile, grown with fermentable 13C substrates, informed dynamic flux balance analysis (dFBA) of the pathogen's genome-scale metabolism. Analyses identified dynamic recruitment of oxidative and supporting reductive pathways, with integration of high-flux amino acid and glycolytic metabolism at alanine's biosynthesis to support efficient energy generation, nitrogen handling and biomass generation. Model predictions informed an approach leveraging the sensitivity of 13C NMR spectroscopy to simultaneously track cellular carbon and nitrogen flow from [U-13C]glucose and [15N]leucine, confirming the formation of [13C,15N]alanine. Findings identify metabolic strategies used by C. difficile to support its rapid colonization and expansion in gut ecosystems.

Incidental discovery of a sacral rib: a case report.

PURPOSE: The observation of an accessory bone joined to the sacrum (suggestive of a sacral rib) prompted us to describe the structure's morphology and its anatomic relationships and to consider its morphogenesis and clinical implications. METHOD: A 38-year-old woman underwent computed tomography, to characterize the extension of a thoracic mass. We compared our observations with the literature data. RESULTS: We observed a voluminous accessory bone located behind and to the right of the sacrum. The bone was articulated with the third sacral vertebra and featured a head and three processes. These characteristics were suggestive of a sacral rib. We also observed involution of the gluteus maximus. CONCLUSION: This accessory bone probably resulted from overdevelopment of a costal process and an absence of fusion with the primitive vertebral body. Sacral ribs are rare and usually asymptomatic but appear to be more prevalent in young women. The adjacent muscles are often abnormal. Awareness of the potential presence of this bone is essential for surgeons who operate on the lumbosacral junction.

Anatomical and biometric study of the radial artery on human cadavers dissected in the anatomy laboratory.

OBJECTIVE: To study the anatomy and biometry of the radial artery and to report the implications of this study for daily practice in Cardiac Surgery. METHOD: Radial arteries from 45 human cadavers (28 males and 17 females, average age 79.2 (92) fixed in 10% formalin were dissected. The proximal and distal internal calibers and lengths of these radial arteries were measured. RESULTS: Our results showed the presence of a single radial artery variation in 2.3% of the entire sample (1.1% of the 90 dissected upper limbs). The distance between the epicondyle and the emergence of the radial artery was 32.4 (6.67) mm in men and 30.7 (9.00) mm in women, with an average of 31.8 (7.58) mm. For the right upper limb, the mean proximal internal caliber of the radial artery was 3.16 (0.56) mm and its mean distal internal caliber was 2.62 (0.66) mm. For the left upper limb, the mean proximal internal caliber of the radial artery was 3.17 (0.59) mm and its mean distal internal caliber was 2.64 (0.68) mm. The mean length of the left radial artery was 197.0 (17) mm. The mean length of the right radial artery was 201.0 (33) mm. CONCLUSION: It is very important to be aware of the possible anatomical variation of the radial artery. Despite its rarity, this knowledge may ensure a better safety and reliability of the harvesting technique for use as a graft.

Identification of RNAs bound by Hfq reveals widespread RNA partners and a sporulation regulator in the human pathogen Clostridioides difficile.

Noncoding RNAs (ncRNA) have emerged as important components of regulatory networks governing bacterial physiology and virulence. Previous deep-sequencing analysis identified a large diversity of ncRNAs in the human enteropathogen Clostridioides (Clostridium) difficile. Some of them are trans-encoded RNAs that could require the RNA chaperone protein Hfq for their action. Recent analysis suggested a pleiotropic role of Hfq in C. difficile with the most pronounced effect on sporulation, a key process during the infectious cycle of this pathogen. However, a global view of RNAs interacting with C. difficile Hfq is missing. In the present study, we performed RNA immunoprecipitation high-throughput sequencing (RIP-Seq) to identify Hfq-associated RNAs in C. difficile. Our work revealed a large set of Hfq-interacting mRNAs and ncRNAs, including mRNA leaders and coding regions, known and potential new ncRNAs. In addition to trans-encoded RNAs, new categories of Hfq ligands were found including cis-antisense RNAs, riboswitches and CRISPR RNAs. ncRNA-mRNA and ncRNA-ncRNA pairings were postulated through computational predictions. Investigation of one of the Hfq-associated ncRNAs, RCd1, suggests that this RNA contributes to the control of late stages of sporulation in C. difficile. Altogether, these data provide essential molecular basis for further studies of post-transcriptional regulatory network in this enteropathogen.

Microsurgical anatomy of the inferior intercavernous sinus.

PURPOSE: Intercavernous sinuses (ICSs) are physiological communications between the cavernous sinuses. The ICSs run between the endosteal and meningeal layers of the dura mater of the sella turcica. Whereas the anterior and posterior ICSs have been frequently described, the inferior ICS (iICS) has been less well studied in the literature; however, poor awareness of the ICS's anatomy can lead to serious problems during transsphenoidal, transsellar surgery. The objective of the present anatomical study was to describe the iICS in detail. METHODS: The study was carried out over a 6-month period in a university hospital's anatomy laboratory, using brains extracted from human cadavers. The brains were injected with colored neoprene latex and dissected to study the iICS (presence or absence, shape, diameter, length, distance between inferior and anterior ICSs, distance between inferior and posterior ICSs, relationships, and boundaries). RESULTS: Seventeen cadaveric specimens were studied, and an iICS was found in all cases (100%). The shape was variously plexiform (47.1%), filiform (35.3%), or punctiform (17.6%). The mean ± standard deviation diameter and length of the iICS were 3.75 ± 2.90 mm and 11.92 ± 2.96 mm, respectively. The mean iICS-anterior ICS and iICS-posterior ICS distances were 5.36 ± 1.99 mm and 7.03 ± 2.28 mm, respectively. CONCLUSION: The iICS has been poorly described in the literature. However, damage to the iICS during transsphenoidal, transsellar surgery could lead to serious vascular complications. A precise radiological assessment appears to be essential for a safe surgical approach.

Discovery of new type I toxin-antitoxin systems adjacent to CRISPR arrays in Clostridium difficile.

Clostridium difficile, a major human enteropathogen, must cope with foreign DNA invaders and multiple stress factors inside the host. We have recently provided an experimental evidence of defensive function of the C. difficile CRISPR (clustered regularly interspaced short palindromic repeats)-Cas (CRISPR-associated) system important for its survival within phage-rich gut communities. Here, we describe the identification of type I toxin-antitoxin (TA) systems with the first functional antisense RNAs in this pathogen. Through the analysis of deep-sequencing data, we demonstrate the general co-localization with CRISPR arrays for the majority of sequenced C. difficile strains. We provide a detailed characterization of the overlapping convergent transcripts for three selected TA pairs. The toxic nature of small membrane proteins is demonstrated by the growth arrest induced by their overexpression. The co-expression of antisense RNA acting as an antitoxin prevented this growth defect. Co-regulation of CRISPR-Cas and type I TA genes by the general stress response Sigma B and biofilm-related factors further suggests a possible link between these systems with a role in recurrent C. difficile infections. Our results provide the first description of genomic links between CRISPR and type I TA systems within defense islands in line with recently emerged concept of functional coupling of immunity and cell dormancy systems in prokaryotes.

A Novel, Hybrid, Stereotactic Approach (Radiosurgery and Dual Ommaya Reservoirs) for the Treatment of Mixed (Polycystic and Solid) Craniopharyngioma.

BACKGROUND: Craniopharyngioma is a difficult entity to treat, which is particularly true for mixed craniopharyngioma (i.e., a mixture of both solid and cystic components). The present case report illustrates a minimally invasive, two-component, stereotactic treatment approach as an alternative to standard microsurgery. CASE DESCRIPTION: A 38-year-old patient presented with progressive intracranial hypertension followed by pan-hypopituitarism, deterioration of the visual field, and cognitive impairment. Brain MRI revealed hydrocephalus and a suprasellar mixed solid and polycystic lesion that was suggestive of craniopharyngioma. Using a robot-assisted, stereotactic treatment approach, we combined the installation of catheters for 2 Ommaya reservoirs with 5-fraction CyberKnife radiosurgery of the solid tumor. The high intracranial pressure and visual field deterioration resolved completely. A partial improvement in endocrine function was noted, and the patient returned to work 6 weeks after surgery. CONCLUSION: A combined, robot-assisted, stereotactic approach to the treatment of mixed (solid and polycystic) craniopharyngioma is a safe alternative to microsurgery. Further studies including larger numbers of patients will be needed to assess the long-term efficacy and morbidity and mortality rates associated with this approach.

Microsurgical anatomy of the subcallosal artery.

BACKGROUND AND PURPOSE: The subcallosal artery [SCA, a branch of the anterior communicating artery (ACoA)] is not well described in the literature. However, the memory disorders that can occur after surgical repair of ruptured ACoA aneurysms might be related to infarction of the SCA. The objective of the present study was to perform a thorough anatomical assessment of the SCA. METHODS: The study was carried out over a 6-month period in a University Hospital's anatomy laboratory, using brains extracted from human cadavers. The brains were injected with colored neoprene latex and dissected to study the SCA's origin, path, termination, diameter, length, and vascularized territories. RESULTS: 21 cadaveric specimens were studied. The mean ± standard deviation diameter and length of the SCA were 0.83 ± 0.57 mm and 38.14 ± 25.11 mm, respectively. The predominantly vascularized territories were the paraterminal gyrus (100%), the parolfactory gyrus (78.95%), the rostrum (84.21%) and genu (78.95%) of the corpus callosum, the lamina terminalis (78.95%), the anterior commissure (63.16%), the anterior cingulate gyrus (47.37%), and the fornix (26.32%). When the SCA supplied the fornix and the anterior cingulate gyrus, it was significantly longer and broader (p < 0.05). CONCLUSION: Anatomic knowledge of the SCA is crucial-especially for the treatment of ACoA aneurysms.

Prognostic factors for survival in adult patients with recurrent glioblastoma: a decision-tree-based model.

We assessed prognostic factors in relation to OS from progression in recurrent glioblastomas. Retrospective multicentric study enrolling 407 (training set) and 370 (external validation set) adult patients with a recurrent supratentorial glioblastoma treated by surgical resection and standard combined chemoradiotherapy as first-line treatment. Four complementary multivariate prognostic models were evaluated: Cox proportional hazards regression modeling, single-tree recursive partitioning, random survival forest, conditional random forest. Median overall survival from progression was 7.6 months (mean, 10.1; range, 0-86) and 8.0 months (mean, 8.5; range, 0-56) in the training and validation sets, respectively (p = 0.900). Using the Cox model in the training set, independent predictors of poorer overall survival from progression included increasing age at histopathological diagnosis (aHR, 1.47; 95% CI [1.03-2.08]; p = 0.032), RTOG-RPA V-VI classes (aHR, 1.38; 95% CI [1.11-1.73]; p = 0.004), decreasing KPS at progression (aHR, 3.46; 95% CI [2.10-5.72]; p < 0.001), while independent predictors of longer overall survival from progression included surgical resection (aHR, 0.57; 95% CI [0.44-0.73]; p < 0.001) and chemotherapy (aHR, 0.41; 95% CI [0.31-0.55]; p < 0.001). Single-tree recursive partitioning identified KPS at progression, surgical resection at progression, chemotherapy at progression, and RTOG-RPA class at histopathological diagnosis, as main survival predictors in the training set, yielding four risk categories highly predictive of overall survival from progression both in training (p < 0.0001) and validation (p < 0.0001) sets. Both random forest approaches identified KPS at progression as the most important survival predictor. Age, KPS at progression, RTOG-RPA classes, surgical resection at progression and chemotherapy at progression are prognostic for survival in recurrent glioblastomas and should inform the treatment decisions.

A median sacral artery anterior to the iliocaval junction: a case report-anatomical considerations and clinical relevance for spine surgery.

BACKGROUND AND IMPORTANCE: The median sacral artery (MSA) is a relatively small vessel that always arises from the posterior, terminal part of the infrarenal aorta. In most cases, the MSA runs behind the iliocaval junction. Here, we describe a very rare case of an MSA running in front of this junction. CASE REPORT: During a human cadaveric dissection of the retroperitoneal area, we unexpectedly observed that the MSA passed in front of the left common iliac vein. CONCLUSION: The anatomy of the MSA has been extensively described and variations are quite rare. On the basis of this specific case, knowledge of the anatomic interactions between the MSA and other lumbar retroperitoneal vessels may help to avoid potential complications during surgery.

Unilateral duplicated abducens nerve coursing through both the sphenopetroclival venous gulf and cavernous sinus: a case report.

In this anatomy report, we describe the first case of abducens nerve duplication limited to the sphenopetroclival venous gulf and the cavernous sinus. The objective point of division of the two duplicated roots was localized at the gulfar face of the dural porus, just distal to the unique cisternal trunk of the abducens nerve, as it pierced the petroclival dural mater. In the gulfar segment, both roots traveled through a variant of Dorello's canal called the "petrosphenoidal canal" and remained separated through the posterior half of the cavernous sinus. Both roots finally fused in the anterior half of the cavernous sinus to innervate the lateral rectus muscle as a single trunk. Although many variants of the abducens nerve have been reported over the recent decades, this anatomic variation has never been previously described and enriches the continuum of abducens nerve variations reported in the literature data. Awareness of this variation is crucial for neurosurgeons, especially during clival or petrosal surgical approaches used for resection of skull base chordomas.

Correction to: Unilateral duplicated abducens nerve coursing through both the sphenopetroclival venous gulf and cavernous sinus: a case report.

In the Original Publication of the article, one of the references was missed to include. This reference and the text citation are given below.

Lymphatic drainage of lung segments in the visceral pleura: a cadaveric study.

PURPOSE: Although peribronchial lymphatic drainage of the lung has been well characterized, lymphatic drainage in the visceral pleura is less well understood. The objective of the present study was to evaluate the lymphatic drainage of lung segments in the visceral pleura. METHODS: Adult, European cadavers were examined. Cadavers with a history of pleural or pulmonary disease were excluded. The cadavers had been refrigerated but not embalmed. The lungs were surgically removed and re-warmed. Blue dye was injected into the subpleural area and into the first draining visceral pleural lymphatic vessel of each lung segment. RESULTS: Twenty-one cadavers (7 males and 14 females; mean age 80.9 years) were dissected an average of 9.8 day postmortem. A total of 380 dye injections (in 95 lobes) were performed. Lymphatic drainage of the visceral pleura followed a segmental pathway in 44.2% of the injections (n = 168) and an intersegmental pathway in 55.8% (n = 212). Drainage was found to be both intersegmental and interlobar in 2.6% of the injections (n = 10). Lymphatic drainage in the visceral pleura followed an intersegmental pathway in 22.8% (n = 13) of right upper lobe injections, 57.9% (n = 22) of right middle lobe injections, 83.3% (n = 75) of right lower lobe injections, 21% (n = 21) of left upper lobe injections, and 85.3% (n = 81) of left lower lobe injections. CONCLUSION: In the lung, lymphatic drainage in the visceral pleura appears to be more intersegmental than the peribronchial pathway is-especially in the lower lobes. The involvement of intersegmental lymphatic drainage in the visceral pleura should now be evaluated during pulmonary resections (and especially sub-lobar resections) for lung cancer.

Recurrent glioblastomas in the elderly after maximal first-line treatment: does preserved overall condition warrant a maximal second-line treatment?

A growing literature supports maximal safe resection followed by standard combined chemoradiotherapy (i.e. maximal first-line therapy) for selected elderly glioblastoma patients. To assess the prognostic factors from recurrence in elderly glioblastoma patients treated by maximal safe resection followed by standard combined chemoradiotherapy as first-line therapy. Multicentric retrospective analysis comparing the prognosis and optimal oncological management of recurrent glioblastomas between 660 adult patients aged of < 70 years (standard group) and 117 patients aged of ≥70 years (elderly group) harboring a supratentorial glioblastoma treated by maximal first-line therapy. From recurrence, both groups did not significantly differ regarding Karnofsky performance status (KPS) (p = 0.482). Oncological treatments from recurrence significantly differed: patients of the elderly group received less frequently oncological treatment from recurrence (p < 0.001), including surgical resection (p < 0.001), Bevacizumab therapy (p < 0.001), and second line chemotherapy other than Temozolomide (p < 0.001). In multivariate analysis, Age ≥70 years was not an independent predictor of overall survival from recurrence (p = 0.602), RTOG-RPA classes 5-6 (p = 0.050) and KPS at recurrence <70 (p < 0.001), available in all cases, were independent significant predictors of shorter overall survival from recurrence. Initial removal of ≥ 90% of enhancing tumor (p = 0.004), initial completion of the standard combined chemoradiotherapy (p = 0.007), oncological treatment from recurrence (p < 0.001), and particularly surgical resection (p < 0.001), Temozolomide (p = 0.046), and Bevacizumab therapy (p = 0.041) were all significant independent predictors of longer overall survival from recurrence. Elderly patients had substandard care from recurrence whereas age did not impact overall survival from recurrence contrary to KPS at recurrence <70. Treatment options from recurrence should include repeat surgery, second line chemotherapy and anti-angiogenic agents.

Gastropancreatic ligament: Description, incidence, and involvement during laparoscopic sleeve gastrectomy.

During laparoscopic sleeve gastrectomy (LSG), adhesions between the stomach and the pancreas are sometimes found, forming a "gastropancreatic ligament" (GPL). However, the GPL has only been described once in the literature, in 1985. The objective of this study was to determine the incidence of the GPL during LSG, describe this structure and assess its effect on the surgical technique. All patients undergoing primary LSG in our institution (n = 240) and patients referred for gastric fistula (GF) after primary LSG (n = 18) between January 2015 and December 2015 were included. The primary endpoint was the incidence of a GPL during primary LSG. The secondary endpoints were the postoperative complication rate, the postoperative GF rate, and the presence of this ligament during reoperation for GF. Among the 240 patients, a GPL was visible in 49 cases (20.4%) and was described as thin in 34 of these (69.4%). Twelve postoperative complications (5%) were observed, including seven major (2.9%). The GF rate was 2% (n = 5), not requiring reoperation. The gastric stenosis rate was 0.4% (n = 1). The GPL had been previously sectioned in one of the five patients (20%) with postoperative GF. During the study period, 18 patients were referred for GF and 14 were reoperated. A non-sectioned GPL, not described in the operating report, was observed in four patients (28.5%). A GPL was identified in 20.4% of cases. Identification of a GPL could be important in the context of LSG, as section of the ligament allows tension-free stapling to be performed and can therefore possibly reduce the risk of postoperative complications, particularly GF. Clin. Anat. 30:336-341, 2017. © 2017 Wiley Periodicals, Inc.

Cyclic diGMP regulates production of sortase substrates of Clostridium difficile and their surface exposure through ZmpI protease-mediated cleavage.

In Gram-positive pathogens, surface proteins may be covalently anchored to the bacterial peptidoglycan by sortase, a cysteine transpeptidase enzyme. In contrast to other Gram-positive bacteria, only one single sortase enzyme, SrtB, is conserved between strains of Clostridium difficile. Sortase-mediated peptidase activity has been reported in vitro, and seven potential substrates have been identified. Here, we demonstrate the functionality of sortase in C. difficile. We identify two sortase-anchored proteins, the putative adhesins CD2831 and CD3246, and determine the cell wall anchor structure of CD2831. The C-terminal PPKTG sorting motif of CD2831 is cleaved between the threonine and glycine residues, and the carboxyl group of threonine is amide-linked to the side chain amino group of diaminopimelic acid within the peptidoglycan peptide stem. We show that CD2831 protein levels are elevated in the presence of high intracellular cyclic diGMP (c-diGMP) concentrations, in agreement with the control of CD2831 expression by a c-diGMP-dependent type II riboswitch. Low c-diGMP levels induce the release of CD2831 and presumably CD3246 from the surface of cells. This regulation is mediated by proteolytic cleavage of CD2831 and CD3246 by the zinc metalloprotease ZmpI, whose expression is controlled by a type I c-diGMP riboswitch. These data reveal a novel regulatory mechanism for expression of two sortase substrates by the secondary messenger c-diGMP, on which surface anchoring is dependent.

Minimally invasive transforaminal lumbar interbody fusion with the ROSA(TM) Spine robot and intraoperative flat-panel CT guidance.

BACKGROUND: Circumferential arthrodesis is commonly used to treat degenerative lumbar diseases. Minimally invasive techniques may enable faster recovery and reduce the incidence of postoperative infections. METHODS: We report on the surgical technique of a transforaminal lumbar interbody fusion (TLIF) procedure performed with the assistance of a new robotic device (ROSA(TM) Spine) and intraoperative flat-panel CT guidance. CONCLUSIONS: The combined use of this new robotic device and intraoperative CT enables accurate and safe arthrodesis in the treatment of degenerative lumbar disc diseases.

Microsurgical anatomy of the Adamkiewicz artery-anterior spinal artery junction.

PURPOSE: The aim of this study is to describe the anterior spinal artery-Adamkiewicz artery (ASA-AKA) junction and establish a classification allowing defining the neurological risk in either thoracoabdominal aorta aneurysm treatment and in anterior or transforaminal thoracolumbar spine surgery. METHODS: Fifteen spinal cords of fresh cadavers were dissected. Both lumbar arteries and ASA were injected with strongly diluted red-colored silicon. RESULTS: The dural crossing of AKA was located on the left side in 86 % of cases, between T8 and T10 in 73.33 % of cases and L1-L2 in 26.67 % of cases. The average diameter of the ascending branch of AKA was 1.10 mm (range 0.8-1.9 mm), and its average length was 30.27 mm (range 12.3-60 mm). The AKA's arch average diameter was 11.3 mm (range 9-20 mm) with an open downward angle average of 20.1° (range 11°-30°). The descending branch of AKA which was a continuation of ASA had an average diameter of 1.33 mm (range 0.8-1.86 mm). The ASA at the top of the arch had an average diameter of 0.74 mm (range 0.2-1.77 mm). According to these findings, we have proposed a new classification with two types of junctions. The type I and its variant correlated to high neurological risk were present in 93.33 % of cases. The type II, correlated to medium or low neurological risk, was present in 6.67 % of cases. CONCLUSION: These anatomical findings allow a planning of the neurological risk before thoracoabdominal aorta aneurysm or thoracolumbar anterior or transforaminal spine surgery.

An unusual, duplicate origin of the anterior choroidal artery with aneurysm: a case report.

BACKGROUND AND IMPORTANCE: Aneurysms of the anterior choroidal artery (AChoA) are rare and often difficult to treat. Variations may be present and must be identified prior to treatment. We report a unique case of a ruptured aneurysm located at the origin of a duplicate branch of the AChoA. CLINICAL PRESENTATION: A 56-year-old male was admitted to our university hospital for coma. A brain CT scan showed a subarachnoid hemorrhage, and CT angiography revealed a duplication of the right AChoA, with an aneurysm located at the branch's origin. We decided to embolize this aneurysm. Four weeks later, our patient was able to transfer to the rehabilitation unit. CONCLUSION: To the best of our knowledge, this is one of the first descriptions of an aneurysm located at the origin of a duplicate branch of the AChoA.

Effect of surgery on periventricular white matter in normal pressure hydrocephalus patients: comparison of two methods of DTI analysis.

BACKGROUND: Diffusion tensor imaging (DTI) is a useful tool for assessing changes that occur in microstructures. We have developed a novel method for region of interest (ROI) delineation in the assessment of DTI parameters in patients with normal pressure hydrocephalus (NPH). PURPOSE: To compare the standard method and our novel method in an evaluation of the impact of surgery on periventricular white matter in patients with NPH. MATERIAL AND METHODS: Ten patients with NPH underwent 3T magnetic resonance imaging (MRI; including 12-direction DTI sequences) before and after surgery. We recorded diffusion parameters (λi, the fractional anisotropy [FA], the apparent diffusion coefficient, and Dr) in the internal capsule (IC) and the body of the corpus callosum (BCC). Using the standard delineation technique, regions of interest (ROIs) were positioned according to anatomical and functional considerations and then filled with several sub-ROIs. The ROIs delineated with our novel technique (extracted as the six sub-ROIs with the lowest standard deviation for the FA) were arranged in two rows (medial and lateral), from the ventricle to the brain surface. RESULTS: The within-ROI homogeneity was higher with the novel method than with the conventional method (P<10(-4)). When the conventional delineation method was applied to the IC data, only λ2 was found to be significantly greater after surgery; in contrast, application of our novel method evidenced a significant decrease in FA and λ1 and a significant increase in λ2 (P<0.05). Both before and after surgery, the FA in the medial row of ROIs was greater than the FA in the lateral row (P<0.01). In the BCC, only λ2 and Dr varied significantly (when evaluated with the novel method). CONCLUSION: Our results show that use of a novel method of DTI data analysis may be more sensitive to local changes induced by surgical procedures. Furthermore, this novel method was able to detect the transmantle pressure gradient related to the regional stress distribution.