Mean Vertical Distance Research Articles

Prevalence of Decay and Tooth Condition Changes Adjacent to Restored Dental Implants: A Retrospective Radiographic Study.

This study examined the association between a dental implant and changes in adjacent teeth over time. Electronic health records of 1818 patients who received a dental implant were retrospectively evaluated over 14 years (2005-2019) in a university setting. The status of the adjacent tooth and vertical and horizontal distance from the implant platform to adjacent teeth were determined using digital intraoral radiographs taken at baseline and the last follow-up visit (1-14 years, median 4 years). In total, 1085 dental implants were evaluated. There were 234 instances of a change in the adjacent tooth. Decay was observed in 83 (7.6%) of adjacent teeth; the mean time to development was 4 years (range 1-14 years). Approximately 9% of adjacent teeth received direct restorations, 4.8% received indirect restorations, 1% received endodontic root canal treatment, and 5.6% were extracted. The mean horizontal distance between the implant platform and the adjacent teeth was 3.56 mm; the mean vertical distance from the contact point to the alveolar crest on the tooth side was 6.2 mm at the first time of the reported decay on X ray. These distances did not significantly influence the occurrence of caries. The prevalence of interproximal contact loss was higher on the mesial of the implant crown at 63% compared with 20% on the distal side. This large retrospective analysis identified that teeth adjacent to a dental implant were at risk of decay and changes in their condition. In addition, the implant-to-tooth distance and inadequate emergence profile may contribute as caries risk factors in addition to hygiene and a high sugar level diet. These findings appear essential for clinicians when making treatment decisions and discussing outcomes with patients.

Optimising central venous catheter placement by comparing cavoatrial junction position to chest X-ray landmarks: Across-sectional study using CT chest reconstruction.

Central venous catheter (CVC) tip placement guided by chest X-ray (CXR) landmarks is currently prone to inconsistency and malpositioning. This study aims to better define the relationship between the cavoatrial junction (CAJ) and selected X-ray landmarks. Chest CTs of 100 patients were retrospectively assessed. CT images were converted to a 'virtual CXR' using a digital workstation, enabling simultaneous localisation of the CAJ and evaluation of CXR landmarks. Vertical distances between the CAJ and selected landmarks were measured for each patient. Measurements were assessed for correlation with age and compared between age groups and sexes. The mean vertical distance of the following landmarks above the CAJ was found: the carina (46.2 mm), the intersection of the bronchus intermedius and the right heart border (7.6 mm) and the superior inflection of the right heart border (Sup-RHB) (13.0 mm). The maximum lateral bulge of the right heart border (Lat-RHB) was 18.4 mm below the CAJ. A new landmark: the mid-superior right heart border, defined as the mid-point between the Sup-RHB and Lat-RHB, was the closest to the CAJ, lying 2.6 mm below the CAJ. We propose that the CVC tip can be placed at the mid-superior right heart border landmark.

Interaction between two large particles in a dry granular shear flow.

The interaction between two large spherical particles, called intruders, in a dry granular flow down an incline is brought to light and studied experimentally and numerically. Several parameters are varied, namely, the size ratio between the intruders and the small flowing particles, the thickness of the granular flow, the incline slope and roughness, and the densities of the intruders with respect to the small-particle density. In all cases, intruders get aligned with the flow. A thorough parametric study shows that a transition occurs between attractive and repulsive regimes of interaction: at steady state, intruders either flow at a defined longitudinal distance, which may be zero with intruders in contact, or stand as far apart as possible. The mean longitudinal and vertical distances between the intruders are found to be tightly linked, with all points plotting the pairs on a single, master curve. The wake and shear effects are shown to control the relative position of the intruders. They may be modulated due to the weight and buoyancy of the intruders, and to local modifications of the collisions between intruders and small flowing particles because of the proximity of the incline bottom or the flow surface.

Alterations in Sphenoid Anatomy in Craniosynostosis: Implications for Fronto-Orbital Advancement.

Fronto-orbital advancement involves removal of the fronto-orbital bandeau. Visualization of the saw blade is lost as it passes through the fronto-orbital-sphenoid junction (FOSJ), placing the temporal lobe at risk of injury. We aim to provide a 3D analysis of the space surrounding this osteotomy to differentiate various types of craniosynostoses. Retrospective cohort. Institutional. Thirty patients with isolated unicoronal synostosis, nonsyndromic bicoronal synostosis, metopic synostosis, Apert syndrome, Crouzon syndrome, and Muenke syndrome. CT scans conducted between 2 months to 2 years of age were 3D reconstructed to compare craniometrics against normal controls. Craniometrics. The mean bone thickness of the FOSJ at the level of the supraorbital rim was significantly small for the Apert, unicoronal and bicoronal groups. The mean vertical height of the middle cranial fossa from the lesser sphenoid wing was significantly greater in the unicoronal group. The mean vertical height of the tip of the temporal lobe from the lateral sphenoid ridge was greater in the unicoronal, isolated bicoronal, and Apert groups. The mean corneal protrusion beyond the lateral orbital rim was significantly greater in the Apert and unicoronal groups. The mean horizontal depth of the orbit was smallest in the Apert group. The mean vertical distance between the dacryon and the foramen cecum, and the mean volume of temporal lobe beneath the sphenoid shelf were the largest in the Apert group. Patients with Apert syndrome have the most unfavorable morphology of the anterior and middle cranial fossae.

Comparative Accuracy of Intraoral and Extraoral Digital Workflows for Short Span Implant Supported Fixed Partial Denture Fabrication: An In Vitro Study.

BACKGROUND The advent of digital impressions using computer-aided design and manufacturing technology (CAD/CAM) has simplified and improved the fabrication of implant prostheses in dentistry. The conventional impression has several drawbacks, including tray selection, material type, impression technique, impression disinfection, and cast model storage. The inaccuracies caused by distortion and contraction of impression material can be minimized with digital impressions. This study aimed to compare digital dental impressions of 10 working casts made using the Pindex laser removable die system to fabricate parallel drill channels vs 10 working casts made using the Di-Lok plastic tray removable die system. MATERIAL AND METHODS An implant master die with 2 dental implant analogs was fabricated. Ten working casts using the Pindex laser removable die system with parallel drill channels and 10 working casts using the Di-Lok plastic tray removable die system were fabricated. The working casts were scanned using an extra-oral laboratory scanner and the implant master model was scanned with an intra-oral scanner. RESULTS The properties of the casts made using the 2 systems were evaluated and analyzed with ANOVA and post hoc Tukey test. The mean horizontal linear distances between A1B1 (P<0.021), A2B2 (P<0.018), C1D1 (P<0.026), C2D2 (P<0.03), B1C1 (P<0.01), and mean vertical distances between B1A2 (P<0.015), C1D2 (P<0.001), B1B2 (P<0.028), and C1C2 (P<0.001) were significantly different between the Pindex system and Di-Lok tray system as compared to intra-oral scans. CONCLUSIONS Complete digital workflow with intra-oral scans were more than the partial digital workflow with extra-oral scans for the Pindex system and Di-Lok tray systems.

Is low carotid bifurcation determined by vertebral level always convenient for surgical approach?

Although high-level carotid bifurcation (HCB) could lead to notable surgical difficulty, the definitive reference point for HCB is unclear. HCB is typically characterized as carotid bifurcation (CB) located higher than the level of the third cervical vertebra (C), however, a major obstacle regarding carotid artery surgical exposure is angle of the mandible (AM). The objective of this study was to investigate CB level, define HCB in relation to AM and vertebral levels, and measure the vertical distance from HCB to ipsilateral AM. Moreover, the percentage of surgically challenged CBs, misclassified as low CBs (LCB) based on vertebral level, was investigated. Patients who underwent neck computed tomography angiography were retrospectively studied. HCBs were classified into two categories: CBs above the C3 and either at or above the ipsilateral AM. Of 172 CBs (86 patients; 57 men, 29 women), CB was mostly found at C3 (44.19%), whereas AM was commonly located at C2 (51.16%). Based on vertebral level and AM, HCBs were detected in 10.47% and 20.35% of CBs, respectively. The association of HCBs determined by either C3 or AM between both sides in each individual was nonsignificant (p>0.05), but HCBs determined by C3 level were predominant in women (OR = 3.58, 95%CI = 1.31-9.80). Considering both C3 and AM, there was 8.72% of HCBs. The remaining 91.28% was classified as LCBs, including 11.63% of CBs located at both C3 and AM which were actually classified as HCBs if determined by AM. In cases of CBs above AM level, the mean vertical distance was as high as 6.56 ±2.41mm.

Mapping out the surgical anatomy of the lingual nerve: a systematic review and meta-analysis.

Understanding the lingual nerve's precise location is crucial to prevent iatrogenic injury. This systematic review seeks to determine the lingual nerve's most probable topographical location in the posterior mandible. Two electronic databases were searched, identifying studies reporting the lingual nerve's position in the posterior mandible. Anatomical data in the vertical and horizontal dimensions at the retromolar and molar regions were collected for meta-analyses. Of the 2,700 unique records identified, 18 studies were included in this review. In the vertical plane, 8.8% (95% confidence interval [CI], 1.0%-21.7%) and 6.3% (95% CI, 1.9%-12.5%) of the lingual nerves coursed above the alveolar crest at the retromolar and third molar regions. The mean vertical distance between the nerve and the alveolar crest ranged from 12.10 to 4.32 mm at the first to third molar regions. In the horizontal plane, 19.9% (95% CI, 0.0%-62.7%) and 35.2% (95% CI, 13.0%-61.1%) of the lingual nerves were in contact with the lingual plate at the retromolar and third molar regions. This systematic review mapped out the anatomical location of the lingual nerve in the posterior mandible, highlighting regions that warrant additional caution during surgeries to avoid iatrogenic lingual nerve injuries.

Comparative Study of Highly Cross-Linked Polyethylene Liner Wear by Hip Center Location Using Elevated Hip Center Technique in Crowe I to III Hip Dysplasia: Outcomes for a Minimum of Eighteen Years of Follow-Up

BackgroundThe literature has reported that supero-lateralization of the femoral head increases the rates of aseptic loosening and prosthesis revision. However, there are few reports on the influence of different hip center positions on liner wear with more than a 15-year follow-up period. MethodsFrom April 2000 to August 2003, 91 patients underwent 108 total hip arthroplasties using a highly cross-linked polyethylene liner combined with zirconia femoral head and cup components. Pelvic radiographs were used to assess the vertical and horizontal distances to the center of the hip and the amount of liner wear. Mean patient age at the time of surgery was 54 years (range, 33 to 73), and mean follow-up duration was 19 years (range, 18 to 21). ResultsAverage liner wear was 0.221 mm, with average annual wear of 0.012 mm/year. Mean vertical and horizontal distances for the hip center were 24.9 and 31.8 mm, respectively. There was no difference in linear wear between patients who had different hip center heights (<20, 20 to 30, and >30 mm), and quadrant partitioning showed no differences across the 4 quadrant zones. ConclusionAt a minimum of 18 years of follow-up in patients having developmental dysplasia of the hip who had different Crowe subtypes and different hip centers, elevated hip center and uncemented fixation techniques using a highly cross-linked polyethylene on ceramic components were associated with very low wear rates and excellent functional scores.

Utility of video-assisted method for identifying and preserving the external branch of the superior laryngeal nerve during thyroidectomy.

The EBSLN is vulnerable to damage during thyroidectomy, results in voice related complications, negatively affect patient quality of life, routine identification of the EBSLN prior to surgical manipulation is necessary for a complication-free thyroidectomy. We aimed to validate a video-assisted procedure for identifying and preserving the external branch of the superior laryngeal nerve (EBSLN) during thyroidectomy and analyze the EBSLN Cernea classification and the localization of the nerve entry point (NEP) from the insertion of the sternothyroid muscle. A prospective descriptive study was performed; 134 patients, who scheduled for lobectomy with an intraglandular tumor max diameter ≤ 4 cm and without extrathyroidal extension, were randomly divided into the video-assisted surgery (VAS) and conventional open surgery (COS) groups. We used the video-assisted surgical procedure for visually identifying the EBSLN directly, and compared the differences in the visual identification rate and total identification rate of the two groups. We also measured the localization of the NEP using the insertion of the sternothyroid muscle as a reference. There was no statistically significant difference in clinical characteristics between the two groups. The visual identification rate and total identification rate were significantly higher in the VAS group than the COS group (91.04% vs. 77.61%, 100% vs. 89.6%). The EBSLN injury rate was 0 in both groups. The mean vertical distance (VD) of the NEP from the sternal thyroid insertion was 1.18 mm (SD 1.12 mm, range, 0-5 mm), with approximately 88.97% of the results occurring within the 0-2 mm range. The mean horizontal distance (HD) was 9.33 mm (SD 5.03 mm, range, 0-30 mm), with over 92.13% of the results occurring within the 5-15 mm range. Both the visual and total identification rates of the EBSLN were significantly higher in the VAS group. This method provided a good visual exposure rate of the EBSLN, aiding in identifying and protecting the EBSLN during thyroidectomy.

Stability of vertical dimension following total arch intrusion

BackgroundThe purpose of this study is to evaluate stability of vertical dimension following total arch intrusion using miniscrews by measuring the change during treatment and relapse amount after more than one year of retention.MethodsThirty patients (6 men, 24 women) were included in this study. Lateral cephalographs were taken with conventional radiography at the start of treatment (T0), after treatment (T1), and at least one year after treatment (T2). The evaluation was performed by measuring changes of selected parameters during treatment and the extent of relapse after more than one year.ResultsDuring total arch intrusion treatment (T1-T0), anterior and posterior teeth intruded significantly. The mean vertical distance between the maxillary posterior teeth and palatal plane was reduced by 2.30 mm (P < 0.001). The mean vertical distance between the maxillary anterior teeth and palatal plane was reduced by 2.04 mm (P < 0.001). The anterior facial height was also reduced by 2.70 mm (P < 0.001). During retention period (T2-T1), the vertical distance between the maxillary anterior teeth and the palatal plane significantly increased by 0.92 mm (P < 0.001). The anterior facial height increased by 0.81 mm (P < 0.01).ConclusionsAnterior facial height significantly decreases after treatment. During retention period, relapse of AFH and maxillary anterior teeth observed. There was no correlation between initial amount of AFH, mandibular plane angle, or SNPog and posttreatment AFH relapse. However, there was a significant correlation between the amount of intrusion of anterior and posterior teeth achieved by the treatment and the extent of relapse.

Retroauricular lymph node flap: An anatomic and surgical feasibility study.

The study investigated the anatomy of the retroauricular lymph node (LN) flap and evaluate its surgical feasibility as a new donor site for a free LN flap in lymphedema surgery. Twelve adult cadavers were examined. The course and perfusion of the anterior auricular artery (AAA) and the location and sizes of the retroauricular LNs were studied. The AAA was available in 87% and absent in 13% specimens. The AAA's origin had a mean vertical distance of 12.2 ± 6.9 mm and a mean horizontal distance of 19.1 ± 4.2 mm from the superior attachment of the ear. The mean diameter of the AAA was 0.8 ± 0.2 mm. The mean number of LN per region was 7.7 ± 2.3, with an average LN size of 4.1 ± 1.9 × 3.2 ± 1.7 mm. The LN were categorized into anterior (G1) and posterior (G2) groups, with a total of 59 and 10 LN, respectively. In a cluster analysis, three LN clusters could be detected across the anterior group (G1). The retroauricular LN flap is a delicate but feasible flap with reliable anatomy, containing a mean of 7.7 LNs.

Predicting central incisor length from the incisive papilla in a multiethnic Northern Nigerian population

ABSTRACT Background: Personalization of complete dentures (CDs) may improve their acceptance by patients. This study sought to develop an individualized predictive model for central incisor length in CDs based on the relationship of the incisive papilla with central incisors. Methods: Seventy-three adult participants were included in the study. The vertical distance (VD) and horizontal distance (HD) from the incisive papilla to the central incisor margins and the mean crown heights (CHs) of both central incisors were determined and recorded along with potential confounders. Bivariate and multivariate analyses were performed to develop a best-fit model equation for predicting the CH from the VD and HD. Results: Thirty-seven males and 36 females (mean age: 33.4 ± 7.8 years) participated in the study. The ovoid arch form (61.6%) was the most common, whereas the square-shaped arch form (4.1%) was the least common. The mean CH, HD, and VD were 10.12 ± 1.02 mm, 10.64 ± 1.36 mm, and 8.00 ± 1.19 mm, respectively. Further, 49% of CH variability (Model 1) was explained by HD (β = 0.61, t = 7.02, P &lt; 0.001) and VD (β = 0.29, t = 3.29, P = 0.002). Participant sex (Model 2) explained another 3% CH variability (β =0.18, t = 2.09, P = 0.04). The predictive equation from Model 2 was CH (mm) = 3.28+ (0.46 × HD) + (0.22 × VD) +0.37 × participant sex. Conclusion: The central incisor CH can be predicted with 52% accuracy using the equation CH (mm) =3.28 + (0.46 × HD) + (0.22 × VD) + 0.37 × participant sex. This finding may aid the fabrication of more individualized dentures.

Mandibular foramen location and its implication to the inferior alveolar nerve block: A retrospective study

Aim: This study was carried out to identify differences in the parameters for locating mandibular foramen (MF) in the central Indian population and the recommended guidelines for the administration of inferior alveolar nerve block (IAN) as mentioned in the dental literature. Methods: Eighty high-resolution full volumes cone-beam computed tomography (CBCT) scans were randomly selected from the radiology database and the scans were rendered, viewed, and measured using the on-demand volumetric imaging software (Anatomage, San Jose, CA). The parameters used in locating the MF/IAN complex were the horizontal distance from the mandibular notch to the midpoint of MF (H); vertical distance from the level of the mandibular occlusal plane to the center of MF (V) and the angle from the contralateral premolar contact area to the MF. Results: Paired t-test was applied. The mean horizontal distance from the mandibular notch to MF was 22.36 ± 2.60 mm in males and 21.05 ± 3.57 mm in females. The mean vertical distance to the occlusal plane was 10.23 ± 4.57 mm in males and 7.42 ± 4.96 mm in females, with a significant difference between the genders (P < 0.05). The mean value for the angulation for the occlusal plane was 39.28° ±5.23° and 37.35° ±3.72° in males and females, respectively. Conclusion: Ethnicity and gender influence the location of the MF/IAN complex. The utilization of long needles, orienting the syringe barrel at an angulation slightly <45° and approximately 10 mm above the mandibular occlusal plane can aid in successfully administering the IAN block.

Anatomical observation and significance of the parietal foramen in Chinese adults.

This study aimed to investigate the incidence, number, diameter, and relative location of the parietal foramen (PF) as well as communication of intracranial and extracranial orifices and their direction, and sagittal suture morphology and length. A total of 280 dry Chinese adult skull specimens from the Department of Anatomy, Southern Medical University, were observed and measured. The occurrence rate and quantity of the PF near the sagittal suture were recorded. The aperture of the PF, the vertical distance between PF and sagittal suture, and the linear distance between PF and lambda were measured using a Vernier calliper. The length of the sagittal suture was measured by a flexible ruler; the direction and communication of intracranial and extracranial orifices were detected using a probe. The total incidence of the PF was 82.86%, slightly higher on the right side than on the left side. The single-foramen type was the most prevalent. The mean diameter of the PF on the left and right sides were 1.02 ± 0.72 mm and 1.07 ± 0.67 mm, respectively, and the diameter of the PF on the sagittal suture was 1.77 ± 0.44 mm. The mean vertical distance between the PF and the sagittal suture was 5.90 ± 2.78 mm and 5.85 ± 2.75 mm on the left and right sides, respectively. The shape of the sagittal suture in the PF area was primarily dentate shaped, with an average arc length of χ = 124.36 ± 7.76 mm, of which the majority were completely healed type. The intracranial and extracranial communication was 39.97%, and the majority of the PF were anteromedial direction. The current study provided an anatomical basis for imaging diagnosis and neurosurgery by investigating the incidence, diameter, and relative location of the PF and intracranial and extracranial communication and direction.

Influence of artificial landmarks on the accuracy of complete arch scans in the partially edentulous maxilla: An in vitro study

Statement of problemScan path length and the presence of edentulous alveolar ridge sections have a negative influence on scanning accuracy. How different artificial landmarks combined with an adapted scanning method affect accuracy is unclear. PurposeThe purpose of this in vitro study was to determine the influence of 2 different artificial landmarks combined with an adapted scanning method on the scanning accuracy of a partially edentulous maxillary model. Material and methodsThe model simulated a maxilla with 6 prepared teeth to accommodate a complete arch fixed partial denture. Five ceramic precision balls (ball center P1–P5), distributed buccally to the dental arch, were used to detect the dimensional and angular changes between the reference model and the intraoral scans. One intraoral scanner (Primescan) was used to make 30 scans each with either the scanning strategy recommended by the manufacturer (M) or with an adapted scanning strategy and the use of a bar (B) or 4 plates (P) as artificial landmarks in the dorsal palate. Data were statistically analyzed using a generalized least squares regression model (α=.05). ResultsScanning with artificial landmarks reduced the maximum absolute distance deviations (M: 249 μm, B: 190 μm, P: 238 μm) and the maximum angle deviations (M: 0.31 degrees, B: 0.28 degrees, P: 0.26 degrees). Vertical distance deviations were improved by 10 to 50% with the use of artificial landmarks. Absolute mean distance deviations were significantly lower for group M (P<.001). In contrast, with artificial landmarks, mean angle (P<.001) and mean vertical distance deviations (P<.014) improved significantly. ConclusionsScanning with artificial landmarks in the dorsal palate combined with an adapted scanning method improved the scanning accuracy and reliability of vertical distance deviations.

Biofilm formation during wastewater treatment: Motility and physiological response of aerobic denitrifying bacteria under ammonia stress based on surface plasmon resonance imaging

A bacterial image analysis system based on surface plasmon resonance imaging was established to investigate the effect of bacterial motility on biofilm formation under high ammonia nitrogen at the single-cell level. The results showed that the bacterial mean rotation speed and vertical motility distance decreased with the increasing concentration of ammonia nitrogen. Ammonia nitrogen inhibited the metabolic activity of the bacteria, decreasing bacterial motility. Bacterial motility was negatively correlated with the biofilm-formation ability. The biofilm formation ability of Enterobacter cloacae strain HNR exposed to ammonia nitrogen was enhanced by reducing its movement and promoting EPS secretion. Genes related to the tricarboxylic acid cycle and oxidative phosphorylation were down-regulated, indicating inhibition of microbial energy metabolism. Genes related to bacterial secretion and lipopolysaccharide synthesis were up-regulated, facilitating the formation of biofilms and enabling the bacteria to resist ammonia nitrogen stress. This study provides new insights into the biofilm formation under ammonia stress.

Ideal entry point and trajectory for C2 pedicle screw placement in basilar invagination patients with high-riding vertebral artery based on 3D computed tomography

BACKGROUNDC2 pedicle screw placement in patients with basilar invagination (BI) is fraught with risks because of a high incidence of anatomical variations and high-riding vertebral artery (HRVA). However, no study can be found in the literature that attempted to identify the ideal entry point and trajectory through the C2 pedicle in BI patients with HRVA. PURPOSETo investigate the parameters of ideal entry point and trajectory for C2 pedicle screw placement in BI patients with HRVA and compare them with those in BI patients without HRVA and patients without BI as control. These parameters would serve as a guide to pedicle screw placement. STUDY DESIGNA retrospective comparative study. PATIENT SAMPLEA total of 396 patients (198 consecutive BI patients and 198 matched patients without BI as control) and 792 unilateral pedicles from April 2017 to October 2021 at two medical centers were included. OUTCOME MEASURESThe insertion parameters of mediolateral angle, surface distance, cephalad angle, and vertical distance from the superior border of the lamina were the primary outcome measures for the reference of C2 pedicle screw placement. Furthermore, factors that affect the primary insertion parameters were assessed via multiple linear regression analyses. METHODAccording to the diagnosis of BI and HRVA, the unilateral pedicles were assigned into HRVA of BI, non-HRVA of BI, HRVA of control, and non-HRVA of control groups. Subgroup analyses based on Goel types A and B were also performed. Moreover, vertebral artery (VA) anomalies that might result in potentially serious complications were identified and systematically compared. RESULTSThe measurements of insertion parameters in BI patients with HRVA indicated a mean mediolateral angle of 27.42°, a mean cephalad angle of 43.02°, a mean surface distance of 9.74 mm, and a mean vertical distance from the superior border of the lamina of 3.85 mm. Compared with that in BI patients without HRVA, the measurements suggested that the entry point in BI patients with HRVA should be shifted upward by 0.38 mm and the trajectory should be angled cephalad by 6.05° and medially by 4.78°. In the control group, changes in the insertion parameters between HRVA and non-HRVA showed a similar trend to the BI group. Multiple linear regression showed that mediolateral angle was significantly associated with the male gender (B=−0.930, p=.017) and the diagnoses of HRVA (B=6.964, p<.001), Goel type A (B=−1.656, p=.003), and Goel type B (B=0.981, p=.030). Moreover, cephalad angle was significantly associated with the length of lateral mass (B=−0.319, p=.001) and the diagnoses of HRVA (B=3.254, p<.001) and Goel type A (B=6.924, p<.001). The VA anomalies were significantly higher in the BI group than in the control group. CONCLUSIONSThe insertion parameters of the ideal entry point and trajectory for C2 screw placement in BI patients with HRVA were remarkably different from those of non-HRVA of BI, HRVA of control, and non-HRVA of control cohorts. Preoperative 3D computed tomography (CT) and CT angiography are highly recommended in such patients to improve intraoperative safety and reduce postoperative complications.

Localization of infraorbital foramen and accessory infraorbital foramen with reference to facial bony landmarks: predictive method and its accuracy.

The infraorbital nerve block is used for mid-facial anesthesia. We aim to determine the location of infraorbital foramen (IOF) and accessory infraorbital foramen (AIOF) with reference to anterior nasal spine (ANS) and the lowest point of zygomaticomaxillary junction (Z) and assess the accuracy of the predictive method. Two hundred and sixteen dry skulls were examined. A reference line was drawn from ANS to Z (line A) and its length was measured (distance A). The location of IOF was predicted by using the mean vertical distance from IOF to line A (line B) which was 15.14±1.99 mm and the mean ratio of the distance between ANS and the intersecting point of line B and line A (distance D) to distance A (D:A) which was 63.35%±3.90%. Eighty-six AIOFs were found. Most of them located superomedial to IOF, except for 3 AIOFs which located in the inferolateral position. For localization the AIOF, the mean vertical distance was 19.34±3.36 mm and the mean ratio was 51.8%±5.90%. No statistically significant difference of the predicted distances for both foramens was found between sex and sides. The accuracy of the predictive method was assessed in 15 embalmed cadavers. Predicted IOFs were 50% accurate and the mean distance error of the predicted IOF was 1.10±1.44 mm lateral and 0.59±1.39 mm inferior to the exact IOF. Therefore, this study provides an alternative method for localization of IOF and AIOF which could be useful in clinical settings.

LINGUAL NERVE IN RELATION TO MANDIBULAR THIRD MOLAR REGION: A CADAVERIC STUDY

Background: The lingual nerve is the terminal branch of the mandibular division of trigeminal nerve. The spatial relationship of lingual nerve to the mandibular alveolar crest varies widely. This variation can be among the gender, age, dental status and between the right and left side of the same sample. This study was aimed to determine the relationship of lingual nerve to mandibular third molar region. Methods: An observational study was carried out from January 2021 to December 2021.The study sample was 15 cadavers including both right and left sides. The lingual nerve was exposed by dissecting the infra temporal region following the standard procedures of Cunninghams Manual of Dissection. The diameter of the lingual nerve, vertical and horizontal distance were measured. The results of all these measurements were tabulated and mean standard deviation were calculated using SPSS version 16. Results: Out of 30 lingual nerves examined, the mean horizontal distance was 3.99 ± 0.96 mm, the mean vertical distance was 12.67 ± 1.76 mm while the diameter of the lingual nerve was 2.46 ± 0.54 mm. Conclusions: The lingual nerve always lies in close proximity of alveolar bone and surgeons operating in this region need to be aware during any surgical interventions or any procedures in this region. A thorough apprehension of the spatial location of the lingual nerve enable to lessen the lingual nerve injury.

An Anatomic Study of the Lateral Dorsal Cutaneous Nerve Using 3-Tesla MRI: A Comparison to Cadaveric Data With Surgical Applications.

The lateral dorsal cutaneous nerve (LDCN) and the anastomotic branch of the sural nerve (AB) are cutaneous sensory nerves at risk of iatrogenic injury during lateral foot surgery. This study is the first to use a large cohort of high-resolution magnetic resonance images (MRIs) of the ankle to better describe the course of these nerves in vivo in order to aid surgeons intraoperatively. Our study intends to build on the "high and inside" approach to the proximal 5MT by accounting for variations in course of the LDCN and AB. One hundred twenty-five 3-tesla (T) MRI studies of the ankle were analyzed. Three reviewers measured the distance from the LDCN and AB to landmarks including the most proximal aspect of the fifth metatarsal tuberosity (5MT) and the peroneus brevis tendon (PBT). Mean vertical distance from the LDCN to the 5MT was 0.8 ± 0.2 cm. Presence of an AB was visualized in 59 of 125 studies (47.2%) and was found 2.2 ± 0.5 cm dorsal to the 5MT. The AB was found to become superior to PBT at a horizontal distance 1.9 ± 0.5 cm proximal to the 5MT. The LDCN was found superior to the PBT at its insertion onto the 5MT in approximately 10% (n = 12) of our studies. During these instances, the LDCN was located an average of 0.3 cm dorsal to the PBT. Our proposed "safe zone" for the approach to the proximal 5MT remains superior to the LDCN and inferior to the AB and avoids crossing directly over either nerve in >95% of analyzed MRI studies. This incision begins 1.5 cm dorsal to the most proximal aspect of the 5MT and extends no more than 1 cm posteriorly. Careful dissection and identification of the LDCN and possible AB is necessary prior to further extension of incision. Level IV, case series.