Landmarks of the sacral hiatus for caudal epidural block: an anatomical study

Background. This study determined the landmarks for caudal epiduralblock (CEB) after morphometric measurements of the sacral hiatuson dry sacral bones. Anatomical features of the sacral hiatusof clinical importance during CEB, along with distances andangles of use in detecting the apex, were measured. This providesdetailed knowledge of the anatomy of the sacral hiatus and practicallandmarks. Methods. Ninety-six dry sacral bones were used. Anatomical measurementswere made with a Vernier caliper accurate to 0.1 mm. Results. Two sacral bones were excluded since they had totalposterior closure defect. Agenesis of the sacral hiatus wasdetected in six sacral bones. As the posterior superior iliacspines impose on the superolateral sacral crests of the sacrum,the latter were accepted as forming the base of a triangle.The distance between the two superolateral sacral crests andthe distances between the sacral apex and the right and leftsuperolateral sacral crest were 66.5 (SD 53.5), 67.1 (10.0)and 67.5 (9.5) mm respectively, on average. Conclusion. The triangle formed between the apex of the sacralhiatus and the superolateral sacral crests was found to havethe features of an equilateral triangle. The sacrum and sacralhiatus are variable anatomical structures. However, the equilateraltriangle located between the apex of the sacral hiatus and superolateralsacral crests will certainly be of use in determining the locationof the sacral hiatus during CEB.     

Ultrasound Guidance in Caudal Epidural Needle Placement

Background: This study was conducted to investigate the feasibility of using ultrasound as an image tool to locate the sacral hiatus accurately for caudal epidural injections.

Methods: Between August 2002 and July 2003, 70 patients (39 male and 31 female patients) with low back pain and sciatica were studied. Soft tissue ultrasonography was performed to locate the sacral hiatus. A 21-gauge caudal epidural needle was inserted and guided by ultrasound to the sacral hiatus and into the caudal epidural space. Proper needle placement was confirmed by fluoroscopy.

Results: In all the recruited patients, the sacral hiatus was located accurately by ultrasound, and the caudal epidural needle was guided successfully to the sacral hiatus and into the caudal epidural space. There was 100% accuracy in caudal epidural needle placement into the caudal epidural space under ultrasound guidance as confirmed by contrast dye fluoroscopy.     

Feasibility and safety of ultrasound-guided caudal epidural glucocorticoid injections

ObjectivesTo assess the feasibility and safety of caudal epidural glucocorticoid injections performed with ultrasound guidance.MethodsWe studied 30 patients with low back pain and nerve root pain related to disk herniation or associated with lumbar spinal stenosis. A caudal epidural injection was performed under ultrasound guidance. Prednisolone acetate, 5 ml, was administered with 10 ml of saline and 5 ml of iodinated contrast agent, providing an epidurogram. Acceptability of the procedure by the patient was assessed. Adverse events occurring immediately after the procedure and within the first month were collected.ResultsThe sacral hiatus was identified in 29 (96.6%) patients. Mean distance between the two sacral cornua was 1.42 cm (range, 0.83–2.13) and mean diameter of the sacral hiatus was 0.60 cm (0,2–1.28). The injection proved feasible in 28 of the 29 patients. The epidurogram indicated that the injection was successful in 27 patients. Mean procedure duration was 15 minutes (30–10). No cerebrospinal fluid reflux occurred. Blood reflux was noted in 9/29 patients and resolved in eight upon needle repositioning. All patients deemed the procedure acceptable. No complications were recorded during the first month.ConclusionUltrasound-guided caudal glucocorticoid injection is a fast, easy-to-perform, well accepted procedure. In our study, an epidurogram confirming that the needle was in the epidural space was obtained in 27 of 28 patients.     

Ultrasound guidance in caudal epidural needle placement

BACKGROUND: This study was conducted to investigate the feasibility of using ultrasound as an image tool to locate the sacral hiatus accurately for caudal epidural injections. METHODS: Between August 2002 and July 2003, 70 patients (39 male and 31 female patients) with low back pain and sciatica were studied. Soft tissue ultrasonography was performed to locate the sacral hiatus. A 21-gauge caudal epidural needle was inserted and guided by ultrasound to the sacral hiatus and into the caudal epidural space. Proper needle placement was confirmed by fluoroscopy. RESULTS: In all the recruited patients, the sacral hiatus was located accurately by ultrasound, and the caudal epidural needle was guided successfully to the sacral hiatus and into the caudal epidural space. There was 100% accuracy in caudal epidural needle placement into the caudal epidural space under ultrasound guidance as confirmed by contrast dye fluoroscopy. CONCLUSIONS: Ultrasound is radiation free, is easy to use, and can provide real-time images in guiding the caudal epidural needle into the caudal epidural space. Ultrasound may therefore be used as an adjuvant tool in caudal needle placement.     

Advances in stereotactic navigation for pelvic surgery

Background

Stereotactic navigation could improve the quality of surgery for rectal cancer. Critical challenges related to soft tissue stereotactic pelvic navigation include the potential difference in patient anatomy between intraoperative lithotomy and preoperative supine position for imaging. The objective of this study was to determine the difference in patient anatomy, sacral tilt, and skin fiducial position between these different patient positions and to investigate the feasibility and optimal set-up for stereotactic pelvic navigation.

Methods

Four consecutive human anatomical specimens were submitted to repeated CT-scans in a supine and several degrees of lithotomy position. Patient anatomy, sacral tilt, and skin fiducial position were compared by means of an image computing platform. In two specimens, a 10-degree wedge was introduced to reduce the natural tilt of the sacrum during the shift from supine to lithotomy position. A simulation of laparoscopic and transanal surgical procedures was performed to assess the accuracy of the stereotactic navigation.

Results

An up-to-supracentimetric change in patient anatomy was noted between different patient positions. This observation was minimized through the application of a wedge. When switching from supine to another position, sacral retroversion occurred independent of the use of a wedge. There was considerable skin fiducial motion between different positions. Accurate stereotactic navigation was obtained with the least registration error (1.9 mm) when the position of the anatomical specimen was registered in a supine position with straight legs, without pneumoperitoneum, using a conventional CT-scan with an identical specimen positioning.

Conclusion

The change in patient anatomy is small during the sacral tilt induced by positional changes when using a 10-degree wedge, allowing for an accurate stereotactic surgical navigation. This opens up new promising opportunities to increase the quality of surgery for rectal cancer cases where it is difficult or impossible to identify and dissect along the anatomical planes.

     

经骶骨纵向固定腰骶滑脱的解剖学研究

目的　对骶骨进行形态学测量 ,研究后路空心钉经骶骨纵向固定腰骶部的安全性。方法　对 2 0例干燥骶骨标本进行CT扫描 ,并进行多平面重建 (MPR)分析 ,测量S1水平骶骨侧块中心的长、宽及面积 ,确定该固定方法的空心钉钉道的长度、安全方向和范围。结果　 2 0例骶骨标本中 ,该固定方法的最窄部分位于S1神经孔水平 ,其几何中心的平均长度为 (37.31± 4 .2 1)mm(2 9～ 4 6 .7mm) ,平均宽度为 (2 1.2 9± 3.5 7)mm(16 .3～ 2 7.4mm) ,平均面积为 (6 .31± 1.2 3)cm2 。通过测量和分析 ,空心钉在矢状面和冠状面的平均最小角度分别为 2 6 .2 9°(2 4 .1°～ 31.3°)和 4 3.6 5°(2 6 .0°～ 5 4 .5°) ,空心钉的平均长度为 85 .2 8mm。结论　相关解剖学数据表明 ,只要进钉的方向及角度正确 ,空心钉经骶骨纵向固定的通道位于骶骨内。术前行CT检查或三维重建 ,制定个体化固定方案 ,该方法可安全地应用于临床。     

Difference in trochanteric thickness between well-aligned and malaligned polished collarless stem

BackgroundSurgical techniques and instruments are continuously evolving to improve placement of components in ideal position. We investigated if there is difference in greater trochanter thickness between the stems in satisfactory position and stems in malposition and to assess the ideal thickness of trochanter for femoral stem placement in neutral position as under reaming of trochanter can result in stem malposition.MethodsMeasurement of greater trochanteric thickness in 95 hip replacements (posterior approach) was performed by a junior doctor and two hip fellows using the trauma CAD/PACS software. The stem was considered neutral if the central axis of femur passes through the distal tip of stem in AP and in varus if the tip of stem was lateral to the femoral shaft axis.Results79 patients had stem in satisfactory position and 16 patients in varus malposition. Mean trochanteric thickness was 12.6 mm (+/−0.56 mm 95%CI, Median 12.5 mm, SD 2.5 mm) in neutral stems while mean thickness in the varus stem was 18.4 mm (+/−1.01 mm 95%CI, Median 17.8 mm, SD 2 mm). There was statistical significant difference between both groups with p< 0.0001 with intra-observer correlation at 99% between the senior personal while correlation was at 80% between the senior personnel and junior doctor. No statistically significant difference was noted in measurements between the senior personal.ConclusionsThe study confirms the significant difference in greater trochanteric thickness between the well aligned and misaligned femoral components. The study raises the possibility that trochanteric thickness can be used as an accessory surgical aid to check if sufficient broaching has been done laterally to allow the stem to be seated in neutral position with an ideal remnant thickness of 12.5 mm. A surgical instrument can be developed to measure the intraoperative thickness of the trochanter which can be a useful tool for young hip surgeons for better placement of components.     

Ultrasound-guided intrathecal anesthesia: Does scanning help?

Intrathecal anesthesia is widely used for many surgical procedures. Multiple attempts at needle placement may cause various complications and patient dissatisfaction.AimTo use a preprocedure ultrasound-guided surface marking, using a midline transverse interlaminar ultrasound view at L4–5 interspace, to guide needle insertion, aiming to decrease needle attempts.Subjects and methodsNinety patients ASA I–II, scheduled for intrathecal anesthesia, were included in the study. Patients were randomly allocated to one of 2 groups. Group I was the ultrasound group and Group II was the surface landmark group. For each block, we recorded patient’s and spine characteristics, number of needle attempts, and patient satisfaction, time for establishing landmarks by preprocedure ultrasound scanning or palpation, time to perform spinal anesthesia, and total time to perform the whole procedure.ResultsSuccessful first needle attempt was in (80%) in ultrasound group (I) and 17 (37.8%) in surface landmark group (II). Needle redirection attempts were 7 (15.6%) in group I and 16 (35.5%) in group II. Second attempt was in 2 (4.4%) in group I and 5 (11.1%) in group II. Third attempt was observed only in group II in 7 (15.6%). There was a significantly more time needed to establish landmarks and complete spinal anesthesia in group I compared to group II (8.7 ± 1.0 vs 5.4 ± 0.4, respectively). Patient’s satisfaction was significantly higher in group I (95.6%) than group II (77.8%).ConclusionPreprocedure ultrasound scanning improved the first needle attempt success rate, decreased redirection or further attempts, and gave better patient satisfaction.     

膝关节半月板根部附着区的解剖学测量

目的:测量国人膝关节内外侧半月板前后根部附着区的解剖学数据,为临床修复半月板根部损伤提供解剖学基础。方法:选取30个国人成人尸体膝关节标本,其中男16例,女14例;死亡年龄35～68(55.6±7.8)岁。对半月板根部附着区结构进行解剖,测量内外侧半月板根部附着区中心点与胫骨内外侧髁间棘、后交叉韧带前缘、内侧胫骨平台软骨后方外侧缘及外侧胫骨平台软骨后方内侧缘等标志点的位置关系和各个附着区的面积。结果:内侧半月板后根部附着区:中心点位于胫骨内侧髁间棘后方(11.73±3.10) mm、外侧(2.77±0.86) mm,后交叉韧带前缘前(2.76±0.76) mm,内侧平台软骨外侧缘外(3.92±0.22) mm,附着区面积(31.29±5.18) mm~2。内侧半月板前根部附着区:中心点位于胫骨内侧髁间棘前方(25.40±5.27) mm、外侧(3.01±0.86) mm,附着区面积(46.18±11.60) mm~2。外侧半月板后根部附着区:中心点位于胫骨外侧髁间棘后方(4.51±1.35)mm、内侧(1.85±0.34) mm,后交叉韧带前缘前(6.91±1.11) mm,外侧平台软骨内侧缘内(3.16±0.96) mm,附着区面积(44.10±6.23) mm~2。外侧半月板前根部附着区:中心点位于胫骨外侧髁间棘前方(12.97±2.92) mm、外侧(1.31±0.22) mm,附着区面积(60.84±14.98) mm~2。结论 :该试验定量描述内外侧半月板前后根部附着区的面积以及其中心点与相应标志点的位置关系,为临床修复半月板根部损伤提供一定的解剖学参考。     

CT fluoroscopy-guided biopsy of pulmonary lesions contacting the interlobar fissure: An analysis of 72 biopsies

PurposeThe purpose of this study was to evaluate retrospectively the safety and diagnostic yield of computed tomography (CT) fluoroscopy-guided biopsy for pulmonary lesions with interlobar fissure contact.Materials and methodsSeventy-two lesions showing interlobar fissure contact (mean size, 15.2 ± 5.3 [SD] mm [range: 5.3–27.0 mm]; mean length of interlobar fissure contact, 8.9 ± 3.6 [SD] mm [range: 2.6–17.5 mm] in 72 patients (33 men, 39 women; mean age, 69.7 ± 10.3 [SD] years; age range: 37–91 years) were evaluated. Multiple variables were assessed to determine the risk factors for diagnostic failure and pneumothorax. Additionally, these variables were compared between these 72 lesions and randomly selected controls (i.e., non-contact lesions).ResultsAll biopsies were technically successful using the transfissural (n = 14) or conventional routes (the route into the lung lobe with the target) with (n = 35) or without (n = 23) possible risk of needle insertion into the interlobar fissure after penetrating the target lesion. Sixty-eight (94.4%) procedures succeeded diagnostically and four (5.6%) failed. There were 27 grade I pneumothorax (37.5%), one (1.4%) grade II bleeding, and five (6.9%) grade IIIa pneumothorax requiring chest tube placement. Groups with and without pneumothorax did not differ significantly in patient-, lesion-, or procedure-related variables. Diagnostic yields and pneumothorax occurrence showed no significant differences between lesions with interlobar fissure contact and controls.ConclusionCT fluoroscopy-guided biopsy of pulmonary lesions with interlobar fissure contact is a safe procedure with a high diagnostic yield. Furthermore, because of potential complications, the transfissural route should be used only when a safer route is not possible.     

Accuracy of blind versus fluoroscopically guided caudal epidural injection.

STUDY DESIGN: A prospective observational study of a case series of patients with low back pain referred for epidural injection of corticosteroid. OBJECTIVES: To evaluate the accuracy of caudal epidural injections performed without the use of fluoroscopic guidance and to determine the value of specific clinical tests performed during the procedure in predicting successful epidural needle placement. SUMMARY OF BACKGROUND DATA: Epidural injection of corticosteroid is one of many treatments currently used in the nonsurgical management of low back pain. The face validity of many studies evaluating the efficacy of epidural corticosteroid injections has been criticized for use of a blind technique. Although there currently is no consensus in the spine literature as to whether epidural injection of corticosteroid (by any technique) is effective, it is imperative first to establish the accuracy of the technique being used. METHODS: A total of 54 consecutive patients underwent fluoroscopically guided caudal epidural injections. Needle insertion was performed blindly (without the use of fluoroscopic guidance), and the success of needle placement was predicted according to the presence of palpable landmarks, palpation of subcutaneous airflow, and the subjective impression that the needle was in a satisfactory position. These clinical criteria then were compared with the position of the needle as seen under fluoroscopy and the spread of radio-opaque contrast in the epidural space after the procedure. RESULTS: Successful injection placement on the first attempt occurred in 74.1% of the patients. Results were improved when anatomic landmarks were identified easily (87.5%) and no air was palpable subcutaneously over the sacrum when injected through the needle (82.9%). The combination of these two signs predicted a successful injection in 91.3% of attempts. CONCLUSIONS: Caudal epidural injection is performed ideally with fluoroscopic guidance as the gold standard for accurate drug placement. If fluoroscopic guidance is unavailable, impractical, or contraindicated, the presence of readily palpable anatomic landmarks at the sacral hiatus and the absence of palpable subcutaneous airflow over the sacrum significantly increase the operator's confidence in the likelihood of an accurate injection even before any products are administered into the epidural space.     

Can the possibility of transverse iliosacral screw fixation for first sacral segment be predicted preoperatively? Results of a computational cadaveric study

ObjectivesThe purpose of this study was to predict the possibility of transverse iliosacral (TIS) screw fixation into the first sacral segment (S₁) and introduce practical anatomical variables using conventional computed tomography (CT) scans.Materials and methodsA total of 82 cadaveric sacra (42 males and 40 females) were used for continuous 1.0-mm slice CT scans, which were imported into Mimics^® software to produce a three-dimensional pelvis model. The anterior height (BH) and superior width (BW) of the elevated sacral segment was measured, followed by verification of the safe zone (SZ_S1 and SZ_S2) in a true lateral view. Their vertical (VD_S1 and VD_S2) and horizontal (HD_S1 and HD_S2) distances were measured. VD_S1 less than 7 mm was classified as impossible sacrum, since the transverse fixation of 7.0 mm-sized IS screw could not be done safely.ResultsFourteen models (16.7%; six females, eight males) were assigned as the impossible sacrum. There was no statistical significance regarding gender (p = 0.626) and height (p = 0.419). The average values were as follows: BW, 31.4 mm (SD 2.9); BH, 16.7 mm (SD 6.8); VD_S1, 13.4 mm (SD 6.1); HD_S1, 22.5 mm (SD 4.5); SZ_S1, 239.5 mm² (SD 137.1); VD_S2, 15.5 mm (SD 3.0); HD_S2, 18.3 mm (SD 2.9); and SZ_S2, 221.1 mm² (SD 68.5). Logistic regression analysis identified BH (p = 0.001) and HD_S1 (p = 0.02) as the only statistically significant variables to predict the possibility. Receiver operating characteristic curve analysis established a cut-off value for BH and HD_S1 of impossible sacrum of 20.6 mm and 18.6 mm, respectively.ConclusionBH and HD_S1 could be used to predict the possibility of TIS screw fixation. If the BH exceeds 20.6 mm or HD_S1 is less than 18.6 mm, TIS screw fixation for S₁ should not be undertaken because of narrowed SZ.     

Defining the pubic symphysis angle with respect to the coronal plane — Clinical and biomechanical considerations

BackgroundFixation strength of constructs placed across the pubic symphysis after injury is dependent on screw length, maximisation of which requires knowledge of the bony anatomy. The aim of this study was to describe the ideal angle of drilling to achieve maximal safe screw placement within the pubic body. Furthermore, the influences of age and gender on the skeletal topography were investigated.MethodsThree hundred CT scans of patients without pelvic injury were analysed to record the angle of the pubic body (APB) with respect to the coronal plane, and the depth of the pubic body (DPB) in the sagittal plane.ResultsMean APB and DPB were 54.69° and 55.35 mm, respectively. Females had a significantly higher mean APB than males (57.29° vs. 52.41°; p < 0.001), whereas males had a significant larger mean DPB (59.13 mm vs. 51.03 mm; p < 0.001). Age had no effect on the mean APB. Mean width of the pubic body at the base was 9.38 mm.ConclusionThe anatomy of this region is reliable in terms of angles and sizes; a drill angle of 55° with respect to the operating table will allow maximal screw length, which should be in the region of 55 mm. The mean width of the pubic body should allow for placement of a 3.5 or 4.5 mm diameter screw.     

Peroneus brevis tendon in proximal 5th metatarsal fractures: Anatomical considerations for safe hook plate placement

IntroductionThe peroneus brevis tendon (PBT) inserts into the proximal aspect of the 5th metatarsal. Metatarsal bone fractures are encountered to be the most common fractures in the foot with predominantly fractures at the base of the fifth metatarsal bone. Mechanism of injury and treatment of the proximal 5th metatarsal fractures vary due to the complex anatomy and diverse biomechanical properties. The purpose of this study was to analyze the footprint of the PBT with regards to the proximal 5th metatarsal fractures and to define a “safe zone” for hook plate placement.Materials and methodsForty-one (41) fixed human lower leg specimens were dissected to expose the PBT insertion. The following footprint characteristics were evaluated: area of insertion (AOI) (mm²), length (mm), width (mm), shape and insertional variations. The position of the main PBT footprint was localized according to the Lawrence and Botte classification for the proximal 5th metatarsal fractures (Zone I–III). A “safe zone” was defined for the fracture-specific hook plate placement.ResultsIn 25 (61%) feet the PBT footprint was situated in Zone I and in 16 feet (39%) in Zone I&II. The mean AOI, length and width measured 54.5 mm² (SD 16.5), 16.0 mm (SD 5.1) and 4.7 mm (SD 1.4), respectively. Analysis of the footprint shapes revealed four different shape types: kidney (29.3%), diamond (22.0%), crescent (31.7%) and oval (17.0%). A “safe zone” for hook plate placement without or minimal interference of the PBT at its insertion could be defined at the lateral aspect of the 5th metatarsal.ConclusionThe majority of the PBT footprints were found in Zone I. Hook plate placement demonstrated to be safe when placed strictly laterally at the proximal aspect of the 5th metatarsal. Precise knowledge of the peroneus brevis anatomy may help to better understand the biomechanical aspects of the proximal 5th metatarsal fractures.     

The Glenoid Vault Outer Cortex (GVOC) radiological reference for shoulder arthroplasty evaluated in aging scapulae

BackgroundAccurate glenoid component positioning is an important determinant of outcome in a shoulder arthroplasty surgery. Optimal glenoid placement is determined using bony landmarks of the scapula. The Glenoid Vault Outer Cortex (GVOC) has been recently described as a new, more accurate radiological reference. This has, however, only been evaluated against current standard references in young patients. Further investigation of the GVOC in older patients is therefore warranted. We, therefore, evaluated the effect of aging on the accuracy and stability of the GVOC, in determining glenoid anatomy as compared to the commonly used Scapular Border (SB) plane.MethodsComputed tomography imaging of 129 individual scapulae was obtained retrospectively from a cohort of patients who had undergone either total body or region-specific computed tomography imaging which included the shoulder region. This comprised of 35 males and 33 females (64 and 65 scapulae respectively) who were aged from 30 to 92 years. Imaging of 54 scapulae was from patients aged ≥60 years. The accuracy of the GVOC plane was then assessed against the SB plane.ResultsIn all patients, the mean difference between estimates using the GVOC plane and the GR (actual) was 2.2° (standard deviation [SD], 4.2) for version, and 1.8° (SD, 4.9) for inclination (P < .001). This contrasted with values of 7.6° (SD, 7.6) for version, and 22.9° (SD, 10.8) for inclination when using the SB reference plane (P < .001). Within the group aged ≥60 years, the mean difference between estimates using the GVOC plane and the glenoid rim (actual) was 3.2° (SD, 4.7) for version and 1.9° (SD, 3.1) for inclination, (P < .001). This contrasted to 10.0° (SD, 7.2) for version, and 23.4° (SD, 10.7) for inclination when using the SB plane (P < .001).Separately it was noted that the GVOC’s relationship to the glenoid rim remained constant throughout aging as opposed to the SB which changed significantly over time effecting estimates of glenoid retroversion.ConclusionsThe GVOC is a new plane of reference developed specifically for the use in shoulder arthroplasty. It is shown to be more accurate and stable in the aging scapulae than the currently used SB plane. The future development of guides and planning softwares that utilize the GVOC may provide an important opportunity for improved accuracy and outcome in shoulder arthroplasty.     

Needle artifact characteristics and insertion accuracy using a 1.2 T open MRI scanner: A phantom study

PurposeTo evaluate the characteristics of needle artifacts and the accuracy of needle insertion using a 1.2 Tesla open magnetic resonance imaging (MRI) system in a phantom.Materials and methodsFirst, the apparent width of the needle on the MRI and the needle tip position error of 16- and 18-gauge MRI-compatible introducer needles and a 17-gauge cryoneedle were examined with different needle angles (0°, 30°, 45°, 60°, and 90°) to the main magnetic field (B0), sequence types (balanced steady-state acquisition with rewound gradient echo [BASG] and T2-weighted fast spin echo [FSE] sequence), and frequency encoding directions. Second, the accuracy of needle insertion was evaluated after 10 MRI fluoroscopy-guided insertions in a phantom.ResultsThe apparent needle widths was larger when the angle of the needle axis relative to B0 was larger. The needles appeared larger on BASG than on T2-weighted FSE images, with the largest apparent widths of 16-, 17-, and 18-gauge needles of 14.3, 11.6, and 11.0 mm, respectively. The apparent needle tip position was always more distal than the actual position on BASG images, with the largest longitudinal error of 4.0 mm. Meanwhile, the 16- and 18-gauge needle tips appeared more proximal on T2-weighted FSE images with right-to-left frequency encoding direction. The mean accuracy of MRI fluoroscopy-guided needle insertion was 3.1 mm.ConclusionThese experiments clarify the characteristics of needle artifacts in a 1.2 Tesla open MRI. With this system, the MRI fluoroscopy-guided needle insertion demonstrated an acceptable accuracy for clinical use.     

Pedicle axis view combined by sacral mapping can decrease fluoroscopic shot count in percutaneous iliosacral screw placement

BackgroundPercutaneous iliosacral screw fixation of the posterior pelvic ring is a demanding procedure with high exposure to radiation. The conventional technique includes the use of three classical projections with the C-arm: inlet, outlet, and true lateral views. A projection in the axis of the upper sacral alar pedicles with a 30° cephalad and 30° ventral oblique view would help in obtaining a more accurate visualization of the safe corridor. Two subcutaneously placed K-wires, one placed horizontally and one vertically, may facilitate the starting point and aim changes by offering the surgeon an option for exactly matching the position of the sacrum with the image. The purpose of this study was to detect if the radiation application could be decreased by our new methodology.MethodsSeventeen patients with pelvic posterior ring disruptions, in which percutaneous iliosacral screw placement was indicated, were included in the study. Group 1 comprised 7 patients in whom conventional projections and technique were used. Group 2 comprised 10 patients in whom 30°–30° projection and sacral mapping technique via two subcutaneous K-wires were applied. Radiation exposure time, total fluoroscopic shot count, fluoroscopic shot count needed for only guide wire and screw placement, radiation dose, and complications were compared between the two groups.ResultsThe median number of fluoroscopic images for guide and screw placement was 132 (56–220) and 29.5 (19–83) in Groups 1 and 2, respectively, and the difference was statistically significant (p < 0.001). The median total fluoroscopic radiation time was 138 (68–234) and 52 (28–77) s in Groups 1 and 2, respectively, and the difference was significant (p < 0.001). Group 1 had a significantly higher median radiation dose than Group 2 [3020 (1502–6032) vs. 1192 (426–2359); (p = 0.001)].ConclusionsIliosacral screw placement with the help of sacral mapping and a fourth view, “30°–30°”, helps the surgeon to markedly reduce the fluoroscopic shots, radiation time and dose during guide wire and screw placement.Level of evidenceTherapeutic, Level II.     

Ultrasonographic anatomy of the long thoracic nerve: A reappraisal using high frequency (24-MHz) probe

PurposeThe purpose of this study was to analyze the potential of ultrasound with a high frequency probe (24-MHz) in the assessment of the long thoracic nerve (LTN) and describe ultrasonographic landmarks that can be used for standardization.Material and methodsUltrasonography analysis of the LTN was done on 2 LTNs in a cadaver specimen and then on 30 LTNs in 15 healthy volunteers (12 men, 3 women; mean age, 28.8 ± 3.8 [SD] years; age range: 24–39 years) by two independent radiologists (R1 and R2) using a 24-MHz probe. Interrater agreement was assessed using Kappa test (K) and intraclass correlation coefficient (ICC).ResultsIn the cadaver, dissection confirmed that the India ink was injected near the LTN in the middle scalene muscle. In volunteers, visibility of the LTN above the clavicle was highly reproducible for the branches arising from C5 (R1: 87% [26/30]; R2: 90% [27/30]; K = 0.83) and from C6 (R1: 100% [30/30]; R2: 97% [29/30]; K = 0.94). Where the nerve emerged from the middle scalene muscle, the mean diameter was 0.85 ± 0.24 (SD) mm (range: 0.4–1.6 mm) for R1 and 0.9 ± 0.23 (SD) mm (range: 0.4–1.7 mm) for R2 (ICC: 0.96; 95% CI: 0.92–0.98%). Along the thoracic wall, where LTN run along the lateral thoracic artery, the mean diameter was 0.83 ± 0.19 (SD) mm (range: 0.5–1.27 mm) for R1 and 0.89 ± 0.21 (SD) mm (range: 0.6–1.2 mm) for R2 (ICC: 0.86; 95% CI: 0.72–0.93%).ConclusionThe LTN can be analyzed with ultrasound using high-frequency probe by using the C5 and C6 roots, the middle scalene muscle above the clavicle and the lateral thoracic artery on the chest wall as landmarks.     

How is quality of life after total hip replacement related to the reconstructed anatomy? A study with low-dose stereoradiography

PurposeThe purpose of this study was to evaluate the relationships between the three-dimensional anatomy of operated hip in standing position using low-dose stereo-radiography imaging system and postoperative hip disability and osteoarthritis outcome score (HOOS) after total hip arthroplasty (THA).Material and methodsA total of 123 patients who underwent THA during a one-year period were included. There were 50 men and 73 women with a mean age of 67.3 ± 13.6 (SD) years (range: 19–89 years). All patients underwent pre- and postoperative low-dose stereo-radiography examination and completed a HOOS form (score from 0 to 100, 100 for full satisfaction). We recorded 16 anatomical parameters before THA, and 15 after THA. After binary transformation of HOOS score using 70 as threshold value, outcome was assessed using logistic or generalised linear models.ResultsA total of 103 patients (103/123; 83.7%) had a HOOS score ≥ 70 and were considered as the satisfied group. A significant difference in pelvic incidence (the angle between a line perpendicular to the sacral plate at its midpoint and a line connecting the same point to the centre of the bicoxofemoral axis) was found between the satisfied 56.4 ± 10.4 (SD)° (range: 31–85°) and the unsatisfied group 48.7 ± 8.9 (SD)° (range: 40–65) (P = 0.006). The relative variation of offset (distance from the centre of rotation of the femoral head to a line bisecting the long axis of the femur) compared to the contralateral hip was ?7% in the satisfied group and 7.2% in the unsatisfied group (P = 0.01).ConclusionPelvic incidence, a parameter independent of the reconstructed anatomy, probably influences the quality of life of patients with THA, via pelvic compensatory capabilities. A loss of femoral offset negatively influences the satisfaction of patients.