Mean Anteroposterior Research Articles

Age-based analysis of pediatric upper airway dimensions using computed tomography imaging.

Recent studies have challenged the historically accepted fact that the larynx is cone-shaped in infants and children. The present study used computed tomography (CT)-based measurements to evaluate airway dimensions. The purpose of this investigation was to determine the dimensional transition between the subglottic area and the cricoid ring in children. This is a retrospective review of 220 CT scans of children aged 1 month to 10 years undergoing radiological evaluation unrelated to airways symptomatology. The CT scans were evaluated in children either sleeping naturally or sedated throughout the study period. Anteroposterior (AP) and Transverse (T) diameters were measured at the subglottic level and at the cricoid ring. The mean (±SD) age was 47.4 ± 33.1 months. The mean AP and transverse diameters were 9.2 ± 1.9 and 7.5 ± 1.6 mm at the subglottic area and 8.5 ± 1.7 and 8.3 ± 1.5 mm at the cricoid. AP dimension showed a decrease from the subglottis to the cricoid ring. A more rapid enlargement of the airway from the subglottis to cricoid ring is observed in the transverse dimension (P < 0.05). A linear progression in the size of airway dimensions between both levels was observed with age (r > 0.7). The narrower transverse dimension compared to the AP diameter suggests that the airway is elliptical immediately below the vocal cords. The present study demonstrates that the airway characteristics in children between the subglottic area and the cricoid change from an elliptical to a round (circular) shape. The cone-shaped airway characteristic, which has been historically proposed, was not observed. Given that subglottic transverse diameter is the smallest area dimension, one must assume this is the most likely area of resistance to the passage of an endotracheal tube rather than only the cricoid.

The Occupancy of the Components in the Cervical Spine and Their Changes with Extension and Flexion.

Study Design Retrospective case series. Objectives The kinematics of the cervical spine has been investigated by many researchers. However, the occupancy of the disk bulges, spinal cord, ligamentum flavum, and the rest of the canal as well as the changes of these structures with motion have not yet been investigated. The goal of this study is to investigate these dynamic changes. Methods The kinetic magnetic resonance images of 248 patients (124 men and 124 women) were evaluated, and the occupancy of each structure for each cervical level at neutral, flexion, and extension were calculated. Results Whole canal anteroposterior (AP) diameters showed significant differences between neutral-extension and flexion-extension at the C4–C5 and C5–C6 levels (p < 0.05). The mean disk bulges showed significant differences between neutral-flexion and flexion-extension at the C4–C5, C5–C6, C6–C7, and C7–T1 levels (p < 0.01). The mean spinal canal AP diameter showed significant differences between flexion-extension and neutral-extension at the C3–C4, C4–C5, C5–C6, and C6–C7 levels (p < 0.05). There were significant differences between neutral-flexion at the C4–C5, C5–C6, and C6–C7 levels (p < 0.05). The mean thickness of the ligamentum flavum showed significant differences between flexion-extension at the C3–C4, C4–C5, C5–C6, and C6–C7 levels (p < 0.001). There were significant differences between neutral-extension at the C3–C4 and C5–C6 levels (p < 0.05). There were significant differences between neutral-flexion at the C5–C6 and C6–C7 levels (p < 0.05). The mean thickness of the spinal cord showed significant differences between neutral-flexion at the C2–C3 and C3–C4 levels (p < 0.05). There were significant differences between flexion-extension at the C3–C4 and C4–C5 levels (p < 0.01). The rest of the canal showed significant differences between neutral-extension and flexion-extension at the C3–C4, C4–C5, C5–C6, and C6–C7 levels (p < 0.005). There were significant differences between neutral-flexion at the C5–C6 and C6–C7 levels (p < 0.01). Conclusions The occupancy of each structure in the cervical spine for each level was revealed by this study. In addition, the dynamic changes in the cervical spine with flexion and extension were seen to have different characteristics for each level.

Cross-sectional sonographic assessment of the posterior interosseous nerve.

Cross-sectional sonographic measurements are considered first-line confirmatory tests in diagnosing peripheral nerve entrapment syndromes. Our aim is to establish normal values of cross-sectional area of the posterior interosseous nerve (PIN) at the arcade of Frohse, the most common site of compression of this nerve. The PIN was identified with ultrasound on 50 healthy adults and 30 cadavers. Measurements of the cross-sectional area (CSA), antero-posterior (AP) and lateral (L) distances were taken immediately proximal and distal to the arcade of Frohse. The mean AP and L distances of the PIN proximal to the arcade of Frohse were 0.111 cm (0 ± 0.021) and 0.266 cm (±0.058), respectively, while the mean AP and L distances of the PIN distal to the arcade of Frohse were 0.085 cm (±0.019) and 0.343 cm (±0.057), respectively. P squared testing showed a statistically significant difference between the AP and lateral distances of the PIN when comparing proximal and distal to the arcade (p ≤ 0.001). However, the mean CSA of the PIN measured immediately proximal to the arcade of Frohse was 0.022 cm(2) (±0.005); immediately distal to the arcade of Frohse, it was 0.023 cm(2) (±0.004). t test showed no statistical difference between the two regions (p = 0.11). Our study has provided reference values for the PIN in healthy individuals at the arcade of Frohse. Although, there is a flattening of the nerve as it enters the supinator muscle, this should not be mistaken for nerve entrapment as the size of the nerve remains consistent.

Dynamic Intraligamentary Stabilization (DIS) for treatment of acute anterior cruciate ligament ruptures: case series experience of the first three years.

BackgroundIn recent years, the scientific discussion has focused on new strategies to enable a torn anterior cruciate ligament (ACL) to heal into mechanically stable scar tissue. Dynamic intraligamentary stabilization (DIS) was first performed in a pilot study of 10 patients. The purpose of the current study was to evaluate whether DIS would lead to similarly sufficient stability and good clinical function in a larger case series.MethodsAcute ACL ruptures were treated by using an internal stabilizer, combined with anatomical repositioning of torn bundles and microfracturing to promote self-healing. Clinical assessment (Tegner, Lysholm, IKDC, and visual analogue scale [VAS] for patient satisfaction scores) and assessment of knee laxity was performed at 3, 6, 12, and 24 months. A one-sample design with a non-inferiority margin was chosen to compare the preoperative and postoperative IKDS and Lysholm scores.Results278 patients with a 6:4 male to female ratio were included. Average patient age was 31 years. Preoperative mean IKDC, Lysholm, and Tegner scores were 98.8, 99.3, and 5.1 points, respectively. The mean anteroposterior (AP) translation difference from the healthy contralateral knee was 4.7 mm preoperatively. After DIS treatment, the mean 12-month IKDC, Lysholm, and Tegner scores were 93.6, 96.2, and 4.9 points, respectively, and the mean AP translation difference was 2.3 mm. All these outcomes were significantly non-inferior to the preoperative or healthy contralateral values (p < 0.0001). Mean patient satisfaction was 8.8 (VAS 0–10). Eight ACL reruptures occurred and 3 patients reported insufficient subjective stability of the knee at the end of the study period.ConclusionsAnatomical repositioning, along with DIS and microfracturing, leads to clinically stable healing of the torn ACL in the large majority of patients. Most patients exhibited almost normal knee function, reported excellent satisfaction, and were able to return to their previous levels of sporting activity. Moreover, this strategy resulted in stable healing of all sutured menisci, which could lower the rate of osteoarthritic changes in future. The present findings support the discussion of a new paradigm in ACL treatment based on preservation and self-healing of the torn ligament.

Cephalometric assessment of the maxillary sinus using computed tomography, from Sokoto, North Western Nigeria

Background: The maxillary sinus is characterized by a significant inter-individual variation. Computed tomography (CT) measurement of sinus dimensions using provides a satisfactory assessment of the maxillary sinus and its conditions. Aim of the Study: To determine the size of the maxillary antrum and compare the depth, width, and height of the maxillary sinus between sexes and to establish a baseline for values in our environment using CT. Materials and Methods: One hundred and thirty subjects (79 males, 51 females), between 20 and 80 years, with normal maxillary sinus CT anatomy, from head CT scans done at the Radiology Department of the Usmanu Danfodiyo University Teaching Hospital Sokoto, were studied. Measurements were taken between the widest points of the sinuses, antero-posterior (AP) and transverse diameters from axial images, craniocaudal diameter from coronal and sagittal images, and volumes were determined by the product of these three-dimensional and slice thickness. Results: In males, the mean craniocaudal, transverse, AP diameters and volume on the right were: 32.21 ± 5.56 mm, 24.18 ± 5.80 mm, 36.94 ± 4.73 mm, and 14.98 ± 6.53 cm 3. On the left, it was 32.38 ± 5.33 mm, 24.12 ± 5.81 mm, 36.84 ± 5.31 mm, and 15.08 ± 6.66 cm 3 respectively. Similarly in females, values on the right were: 30.93 ± 6.09 mm, 23.14 ± 4.70 mm, 36.29 ± 4.71 mm and 13.26 ± 5.04 cm 3, and left was, 31.14 ± 6.00 mm, 23.69 ± 5.50 mm, 36.43 ± 4.64 mm and 16.06 ± 17.96 cm 3 respectively. Conclusions: CT measurements of the maxillary sinus dimensions are larger in males; however, females had higher left sinus volume.

A three-dimensional computed tomography study of distal femoral morphology in Japanese patients: gender differences and component fit.

Previous anthropometric studies have reported gender differences in distal femoral morphology. However, to date, very few studies have investigated the knee morphology of Japanese adults and possible gender differences. The purpose of this study was to examine the distal femoral morphology of Japanese patients, to characterize anatomical differences between male and female, and to evaluate the need to create gender-specific knee prostheses. We evaluated 80 knees in 40 male and 40 female Japanese patients scheduled for total knee arthroplasty (TKA). The mediolateral (ML) and anteroposterior (AP) dimensions of the knees at different levels were measured preoperatively using three-dimensional computed tomography, and ML/AP aspect ratios were calculated. On the distal femoral cut surface, the mean ML widths were 74.9 mm for male and 65.1mm for female, and the mean AP lengths were 63.4mm for male and 58.9 mm for female. Such values were generally smaller compared to data from European and North American studies. In this study, the mean ML/AP aspect ratios were 1.31 for male and 1.25 for female, higher than those from non-Asian regions. The ML/AP ratios of Japanese patients were negatively correlated with distal femoral AP length. Japanese female had a relatively narrower femoral width for a given AP length than male. Our study suggests the utility of Japanese-specific implants and provides useful insights for manufacturers to design components of appropriate sizes and aspect ratios for Japanese TKA patients.

CT based evaluation of odontoid morphology in the Indian population

Background:Anterior fixation using two 3.5 mm screws is typically recommended for type II odontoid fractures. However, it is unsuitable in patients with an odontoid diameter of <9.0 mm. There is no data regarding the morphology of odontoid process in the Indian population. The aim of our study was to: a) Measure the external diameters of odontoid process in the Indian population using CT scan and thus determine the feasibility of two 3.5 mm screw fixation in them. b) Determine if any correlation exists between body height (Ht) and weight (Wt) and external odontoid diameters.Materials and Methods:CT images of odontoid process of 100 consecutive patients were analyzed. Antero- posterior (AP) and transverse (TD), outer diameters of the odontoid process were measured from the base and at 1 mm interval upwards on axial CT images.Results:The mean AP and mean TD were 11.52 mm and 9.85 mm, respectively. Fifty-five (55%) of the patients had at least one TD <9.0 mm. Five (5%) patients had at least one TD <7.4 mm. None of the patients had any diameter <5.5 mm. Body Ht correlated significantly with mean AP and mean TD of the odontoid process (AP: r = 0.276, P = 0.013; TD: r = 0.359, P = 0.001), whereas body Wt correlated significantly only with mean TD (AP: r = 0.162, P = 0.15; TD: r = 0.297, P = 0.007).Conclusion:More than half of the study population (55%) was unsuitable for two 3.5 mm screw fixation for type II odontoid fracture. Two 2.7 mm screws can be safely used in 95% of the population. A 4.5 mm Herbert screw can be safely used in the entire population. We recommend two 2.7 mm screws or a 4.5 mm Herbert screw for fixation of these fractures in the Indian population. Body height showed a significant correlation with external odontoid diameters, whereas weight showed significant correlation only with TD of the odontoid process.

Computed Tomography Morphometric Study of Gender Differences in Osteoarthritis Proximal Tibias

One hundred and thirty osteoarthritic knees(65 males, 65 females) from a Chinese population were measured by computed tomography for tibial mediolateral (ML), middle anteroposterior (AP), medial anteroposterior (MAP), lateral anteroposterior (LAP) dimensions and ML/AP aspect ratio. The ML/AP aspect ratio were classified into 3 groups based on AP dimensions(<48 mm, 48–52 mm, >52 mm) to compare the morphologic differences of proximal tibia between males and females. The mean ML, AP, MAP and LAP dimensions of proximal tibia showed significant differences for sex (P < .01). We found a progressively decreased in the ML/AP aspect ratio with an increasing AP dimension, and males have larger ML/AP aspect ratio than that of females under a given AP dimension (P < .01). This indicates that under a given AP dimension prosthesis, the tibial ML dimension have the potential to be undersized in males and to overhang in females. This study may provide important reference in designing proper gender-specific tibia prosthesis with different ML/AP aspect ratio for Chinese males and females.

Laminar Closure After Classic Hirabayashi Open-Door Laminoplasty

Prospective analysis of preoperative and postoperative radiological data. To assess the incidence and extent of laminar closure after Hirabayashi open-door laminoplasty, as determined by multi-detector computed tomography (CT), and to investigate the influence of this phenomenon on spinal cord compression, as shown by magnetic resonance imaging (MRI). Although laminar closure occurs after laminoplasty, little is known about its progression or its effect on restenosis of the spinal canal. Thirty-five patients (132 laminae) underwent classic Hirabayashi laminoplasty and were followed for at least 12 months. Multi-detector CT was performed preoperatively, at 1 week, or less, and 6 months after surgery. At each level, the anteroposterior (AP) diameter of the spinal canal and the angle of the opened lamina were measured. MRI was performed preoperatively and 1 year after surgery to evaluate the severity of cord compression based on a six-grade classification system. The mean AP diameter and the mean opening angle increased immediately after surgery (P <0.05 each) and decreased 6 months after surgery (P < 0.0001 each), with the AP diameter and opening angle decreasing by 9.4% and 10.2%, respectively. CT at 6 months showed fusion of the hinge in 91% of opened laminae. Segments with high-grade cord compression (grade ≥3) at 1 year showed greater decreases in AP diameter and opening angle (P < 0.05). After classic Hirabayashi open-door laminoplasty, opened laminae showed reclosure at 6 months, with approximately 10% decrease in AP diameter and opening angle. Postoperative lamina closure was associated with recurrent spinal cord compression, suggesting the need for other augmenting techniques that keep the laminae opened.

Review of the dimensions of the median nerve and carpal tunnel using sonography in asymptomatic adults

The study aims to establish the normal range of all sonologic measurements of carpal tunnel (CT) structures in an asymptomatic population. Sonological evaluation of 150 wrists in 75 asymptomatic adults was performed. The cross-sectional area (CSA) of the median nerve at four levels, the flattening ratio (FR) at three levels, the antero-posterior (AP) diameter of the CT and the distance of the transverse carpal ligament (TCL) from the trapezium-hamate (TmH) line were measured. The mean (standard deviation (SD)) CSA of the median nerve at the distal forearm, CT inlet, mid and outlet were 6.8 (1.3), 7.4 (1.1), 7.5 (1.0), 7.1 (1.0) mm(2) , respectively. The mean (SD) FR at the CT inlet, mid and outlet were 2.66 (0.54), 2.55 (0.54), 3.69 (0.82), respectively. The mean (SD) AP diameter of the CT was 10.4 mm (1.1). Volar bowing of the retinaculum was seen in 7.3% of normal wrists. The normal range at two SDs of the CSA of the median nerve at the inlet was 5.2-9.6 mm(2) . The upper limit of volar bowing of the flexor retinaculum was 0.8 mm. The FR overlaps with values obtained in other studies of patients with carpal tunnel syndrome. The mean AP diameter of the CT was 10.4 mm (SD 1.1). To the best of our knowledge, this is the largest study performed in an asymptomatic population assessing the different sonological parameters related to the CT.

Relapse in Fronto-Orbital Advancement

Our unit policy in fronto-orbital advancement (FOA) and remodeling has been initial overcorrection to improve the ultimate aesthetic outcome of surgery. To assess relapse of anteroposterior (AP) correction in patients with cranial synostosis undergoing FOA and remodeling, a retrospective pilot study identified patients from the unit database. Serial AP calvarial measurements were used to record surgical and postsurgical changes. Patients showing a change in measurements toward preoperative values were considered to have relapsed. Associated factors were recorded, and statistical analysis was carried out using SPSS.Thirty-one patients (female n = 10, male n = 21) with a median age at surgery of 17 months and a mean weight of 11 kg were included in the study. The mean hospital stay was 7 days. The mean advancement was 13 (SD, 4) mm, and relapse occurred in 65% (20/31). Mean AP relapse at 5 months was 6.2 mm. No patient required subsequent FOA. No significant correlation was found between relapse and age, weight, hospital stay, and syndromic status. Anteroposterior relapse of the fronto-orbital segment occurred in two thirds (65%) of our cohort at 5 months. A prospective study is now under way to analyze this further. The results of this pilot study suggest that strategies to minimize or to compensate for relapse may enhance the ultimate surgical result.

Dose variation during hypofractionated image-guided radiotherapy for prostate cancer: Planned versus delivered

To determine variation in the actual doses delivered to the organs at risk and the target in patients treated for localized carcinoma of the prostate using image-guided radiotherapy. Ten patients treated with helical TomoTherapy underwent daily target localization with megavoltage CT, on which the prostate, rectum and bladder were recontoured. The planned adaptive module was used for dose recalculation. The study endpoints were to analyse the variations in certain dose-volume parameters of the rectum and bladder (BD 2cc , RD 2cc , BV 100% , BV 70% , RV 100% , RV 70% ), the maximum anteroposterior (AP) and lateral rectal diameters, the volume of the CTV receiving 100% of the prescription dose (CTV V 100% ) and the dose to 100% of the CTV (CTV D 100% ). The difference between the planned and delivered target doses (CTV V100% and CTV D100%) was small and clinically insignificant indicating adequate target coverage during treatment. There was a large variation in the AP and lateral rectal diameters, with no particular trend or correlation to dose parameters being noted during the course of treatment. The mean AP diameter during treatment was significantly less than the planned diameter (P < 0.05). The percentage of fractions where the delivered BV100%, BV70%, RV100%, and RV70% was more than the planned values were 42.8%, 17.1%, 45.4%, and 44.4%, respectively. The delivered BD2cc and RD2cc were similar to their planned values. This study demonstrates the usefulness of daily soft tissue image guidance in negating the effects of physiological variation of the rectum and bladder on the dose delivered to the prostate.

Dysfunction of the posterior cruciate ligament in total knee arthroplasty

Total knee arthroplasty (TKA) is typically carried out either with retention (CR) of the posterior cruciate ligament (PCL) or with sacrifice of this ligament and implantation of a posterior stabilised (PS) prosthesis. This paper investigates a comparison of PCL function in knees treated for osteoarthritis with TKA where the PCL is preserved to those knees treated with TKA and posterior stabilisation. One hundred and sixty-eight patients (232 knees) who had undergone TKA with either a PS or CR implant were included in the study. Clinical assessment included antero-posterior (AP) laxity and posterior sag assessment with an arthrometer. The mean AP laxity at 90° of flexion for CR TKAs was 6.5mm (±3.1) and was the same [6.5mm (±2.4)] as in the PS group. However, 56% of the PCL-preserved knees had a posterior sag of over 3mm compared to 18% of the knees in the PS group. The American Knee Society Scores for either group showed that, although the mean function score was the same, the knee score was superior in the PS group (77 vs. 84). The range of motion was also superior in the PS group (111° vs. 105°). The use of the PS prosthesis for TKA provides a more predictable outcome with regard to posterior sag and a better maximum flexion than a CR implant.

Inter- and Intrafraction Variability in Liver Position in Non–Breath-Hold Stereotactic Body Radiotherapy

The inter- and intrafraction variability of liver position was assessed in patients with liver cancer treated with kilovoltage cone-beam computed tomography (CBCT)-guided stereotactic body radiotherapy. A total of 314 CBCT scans obtained in the treatment position immediately before and after each fraction were evaluated from 29 patients undergoing six-fraction, non-breath-hold stereotactic body radiotherapy for unresectable liver cancer. Off-line, the CBCT scans were sorted into 10 bins, according to the phase of respiration. The liver position (relative to the vertebral bodies) was measured using rigid alignment of the exhale CBCT liver with the exhale planning CT liver, following the alignment of the vertebrae. The interfraction liver position change was measured by comparing the pretreatment CBCT scans, and the intrafraction change was measured from the CBCT scans obtained immediately before and after each fraction. The mean amplitude of liver motion for all patients was 1.8 mm (range, 0.1-5.7), 8.0 mm (range, 0.1-18.8), and 4.3 mm (range 0.1-12.1) in the medial-lateral (ML), craniocaudal (CC), and anteroposterior (AP) directions, respectively. The mean absolute ML, CC, and AP interfraction changes in liver position were 2.0 mm (90th percentile, 4.2), 3.5 mm (90th percentile, 7.3), and 2.3 mm (90th percentile, 4.7). The mean absolute intrafraction ML, CC, and AP changes were 1.3 mm (90th percentile, 2.9), 1.6 mm (90th percentile, 3.6), and 1.5 mm (90th percentile, 3.1), respectively. The interfraction changes were significantly larger than the intrafraction changes, with a CC systematic error of 2.9 and 1.1 mm, respectively. The intraobserver reproducibility (sigma, n = 29 fractions) was 1.3 mm in the ML, 1.4 mm in the CC, and 1.6 mm in the AP direction. Interfraction liver position changes relative to the vertebral bodies are an important source of geometric uncertainty, providing a rationale for prefraction soft-tissue image guidance. The intrafraction change in liver position from the beginning to the end of each fraction was small for most patients.

Pelvic Shape and Prostate Motion

To study the impact of pelvic shape on prostate motion and the implications for radiotherapy target design and treatment outcomes. A total of 3741 measurements (daily shift moves in the 3 principal directions) on 29 consecutive prostate cancer patients were reviewed. All patients had 3 prostatic fiducials placed and were tracked using kilovoltage on-board imaging. Pelvic shape was categorized into android (n = 21; 2580 measurements) and gynecoid (n = 8; 1161 measurements) (defined geometrically by postoutlet to preoutlet ratio). Multivariate analyses of means/standard deviations in each principal direction were performed using major demographic, disease, anatomic, and treatment factors as covariates. Toxicity rates were compared using Fisher exact test. On simple t test comparisons, no mean/standard deviation reached significance, although there was a nonsignificant (0.38 vs. 0.31 cm, P = 0.083) larger mean antero-posterior (AP) movement in the gynecoid group. On multivariate analyses, gynecoid shape (P = 0.032) significantly predicted for mean AP movement, and gynecoid shape (P = 0.045) significantly predicted for standard deviation of AP movement. Pelvic AP and RL dimensions also correlated with mean and standard movement along the respective axes. There were no differences between rates of acute (GI or GU) toxicity (P = 0.456) between the android and gynecoid groups. Treatment strategies that do not employ daily motion tracking may require wider planning target volume margins in gynecoid patients. Tracking the prostate daily, as done in our case using fiducials/on-board imaging, can counter differences in pelvic shape to produce similar treatment outcomes.

Instrumented measurements of knee laxity: KT-1000 versus navigation

The KT-1000 is widely accepted as a tool for the instrumented measurement of the antero-posterior (AP) tibial translation. The aim of this study is to compare the data obtained with the KT-1000 in ACL deficient knees with the data obtained using a navigation system during "in vivo" ACL reconstruction procedures and to validate the accuracy of the KT-1000. An ACL reconstruction was performed using computer aided surgical navigation (Orthopilot, B-Braun, Aesculap, Tuttlingen, Germany) in 30 patients. AP laxity measurements were obtained for all patients using KT-1000 arthrometer (in a conscious state and under general anaesthesia) and during surgery using the navigation system, always at 30 degrees of knee flexion. The mean AP translation was 14 +/- 4 and 15.6 +/- 3.8 mm using the KT-1000 in conscious and under general anaesthesia, respectively (P = 0.02) and 16.1 +/- 3.7 mm using navigation. Measurements obtained with the KT-1000 under general anaesthesia were no different from those obtained "in vivo" with the navigation system (P = 0.37). In conclusion this study validates the accuracy of the KT-1000 to exactly calculate AP translation of the tibia, in comparison with the more accurate measurements obtained using a navigation system.

Silicone Intubation and Dacryocystographic Finding in Incomplete Nasolacrimal Duct Obstruction

Purpose: To assess the relationship between the internal diameter of the nasolacrimal duct and the success rate of silicone tube intubation in incomplete nasolacrimal duct obstruction patients with epiphora. Methods: Dacryocystography was performed 80 patients with symptoms of epiphora and the anteroposterior (AP) diameters and the lateral diameters of the nasolacrimal ducts were measured. These measurements were compared between the group of patients who demonstrated improvement after the operation, and the group without symptom improvement. Results: The mean length of the nasolacrimal duct in the group with nasolacrimal stenosis was 11.70.1 mm, the mean lateral diameter was 1.00.2 mm, and the mean AP diameter was 1.10.1 mm. The AP diameter of the symptomatic nasolacrimal duct in the group with successful postoperative results was 1.10.1 mm, and 0.90.1 mm in the group with unsuccessful results. The group with successful postoperative results had an average of 18.17.0% stenosis in the side of the eye with nasolacrimal duct stenosis compared with the asymptomatic side, and the group with unsuccessful postoperative results had an average of 34%3.6% stenosis. Conclusions: In cases with nasolacrimal duct stenosis, the success rate of silicone tube intubation was high when the AP diameter of the nasolacrimal duct was more than 1.10.1 mm and when the stenosis was less than 18.17.0% in the symptomatic side compared with the opposite side. These results are expected to help predict the success rates when preoperatively planning silicone tube intubation.

Normal reference values of Southwick's anteroposterior angle in prepubertal and pubertal normal adolescents

Measurement of the Southwick's anteroposterior (AP) angle (shaft epiphysis proximal femoral AP angle) is not only a useful tool for planning the surgical treatment of deformities caused by slipped capital femoral epiphysis, but seems to be also important for recognizing the risk of epiphysiolysis development in obese patients (increased AP angle) or to confirm the diagnosis of slipped capital femoral epiphysis (decreased AP angle). To establish normal reference values of the Southwick's AP angle, we studied 97 normal nonobese adolescents (42 females, 55 males), with ages ranging between 8 and 16 years. The mean (SD) AP angle was 151.2 (5.0), ranging from 140 to 164. The limits for the first (p25) and third (p75) quartiles were 148 and 155, respectively. No difference was observed in the AP angle in males when compared with females. The AP angle was evaluated according to sex, chronological age, bone age, weight, height, and pubertal stage of development. We observed an inverse correlation of the AP angle with chronological age (r=-0.57) and bone age (r=-0.52). A weak inverse correlation was also found with stature (r=-0.33). Only a tendency toward an inverse correlation with weight (r=-0.27) or body mass index (r=-0.26) was observed. No significant correlation with the pubertal stage was found. When chronological and bone ages were divided into intervals, a significant reduction of the AP angle was observed only in patients older than 14 years compared with those younger than 10 years of age. In this study, we propose that the AP angle should be considered to be normal if it varies between 148 and 155. We conclude that the normal AP angle does not depend on sex; however, it tends to decrease with stature, and chronological and bone ages. In the normal weight range also, the AP angle decreases, contrasting with our previous findings in obese adolescents, in which the AP angle increases with the severity of obesity.

A new radiological index for assessing asphericity of the femoral head in cam impingement

Femoroacetabular cam impingement is thought to be a cause of premature osteoarthritis of the hip. The presence of cam malformation was determined in 2803 standardised anteroposterior (AP) pelvic radiographs from the Copenhagen Osteoarthritis Study by measuring the alpha (alpha) angle and the triangular index, a new measure of asphericity of the femoral head. In addition, the alpha-angle and the triangular index were assessed on the AP and lateral hip radiographs of 82 men and 82 women randomly selected from patients scheduled for total hip replacement (THR). The influence of varying femoral rotation on the alpha angle and the triangular index was also determined in femoral specimens under experimental conditions. From the 2803 radiographs the mean AP alpha-angle was 55 degrees (30 degrees to 100 degrees ) in men and 45 degrees (34 degrees to 108 degrees ) in women. Approximately 6% of men and 2% of women had cam malformation. The alpha-angle and triangular index were highly inter-related. Of those patients scheduled for THR, 36 men (44%) and 28 women (35%) had cam malformation identifiable on the AP radiographs. The triangular index proved to be more reliable in detecting cam malformation when the hip was held in varying degrees of rotation. The combination of the alpha-angle and the triangular index will allow examination of historical radiographs for epidemiological purposes in following the natural history of the cam deformity.

Computed Tomographic Evaluation of the Odontoid Process for Two-Screw Fixation in Type-II Fracture: A Malaysian Perspective

To measure the diameter of the odontoid process in a Malaysian population using computed tomographic (CT) scan and determine the feasibility of treating type-II odontoid fractures using 2 cortical screws. CT images of the odontoid process of 85 patients aged 18 to 80 years were analysed; 69 (81%) were male (mean age, 44 years) and 16 (19%) were female (mean age, 48 years). Both anteroposterior (AP) and transverse diameters of the odontoid process were measured via axial CT images at 3 different levels: the base of the odontoid process and 1.2 mm and 2.4 mm above the base. The mean AP and transverse diameters of the odontoid process in men were 11.3 (range, 10.0-12.6; standard deviation [SD], 0.7) mm and 10.2 (range, 8.5-12.3; SD, 0.8) mm respectively, whereas in women were 10.9 (range, 9.4-13.2; SD, 0.8) mm and 10.1 (range, 7.9-11.6; SD, 0.9) mm respectively. The difference in corresponding mean dimensions between men and women was not statistically significant. The mean AP diameter was significantly larger than the mean transverse diameter. At the base and 1.2 mm and 2.4 mm above the base, the respective transverse diameters of 4 (5%), 13 (15%), and 24 (28%) of the patients were <9.0 mm. None had an odontoid AP diameter of <9.0 mm at any level. Two 3.5-mm cortical screws appear too big for fixation in one third of our sample presenting with type-II odontoid fracture. Fixation by two 2.7-mm screws is recommended for Malaysians and other Asian populations.