We aimed to quantify and compare surgical exposure and freedom at the anterior communicating artery (ACoA) complex using pterional (PT), supraorbital (SO), extended supraorbital withorbital osteotomy (SOO), and endonasal endoscopic transtubercular-transplanum (EEATT) approaches.
Right-sided PT, SO, SOO, and EEATT approaches were performed using 10 cadaveric heads. Surgical exposure and freedom (horizontal and vertical attack angle) at the ACoA complex were measured. The farthest clipping distance from ACoA to A1 (precommunicating segment of the anterior cerebral artery)/A2 (postcommunicating segment of the anterior cerebral artery) was also quantified.
There was a significantly greater exposure length of right A1 in the PT approach (12.20 ± 2.48 mm) compared with the EEATT approach (9.52 ± 2.09 mm; P = 0.029). Among the 4 approaches, EEATT provided the shortest clipping distance for right A1 (6.56 ± 1.33 mm; P = 0.001) and the longest clipping distance for right A2 (3.36 ± 1.24 mm; P = 0.003). SO, SOO, and PT approaches (2.9 ± 0.9) had more observations on perforators from ACoA than did the EEATT approach (2.0 ± 0.66; P = 0.029). The EEATT approach (50.90 ± 17.45 mm2) provided better exposure of the superior part of the ACoA complex compared with the SO approach (29.37 ± 17.27 mm2; P = 0.05). PT and SOO approaches provided the greatest horizontal (36.88° ± 5.85°) and vertical (19.37° ± 4.70°) attack angle, respectively.
The SO, SOO, and PT approaches provided a better hemilateral view of the ACoA complex and similar surgical exposure, whereas the EEATT approach offered greater exposure in the upper part of the ACoA complex, with relatively limited exposure of perforators from ACoA and surgical freedom. The EEATT approach can play a role in exposure of lesion involving the ACoA complex.

BACKGROUND: Safe placement of pedicle screws without jeopardizing neurovascular structures medially and anteriorly is important during spine surgery. Inferior breach of pedicle is also dangerous due to low margin of error. Lumbar morphology and identical pedicle orientation at L1 to L5 shown on CT scan of young Taiwanese patients (90 patients) were analyzed and compared with findings reported for Caucasian subjects.
METHODS: Previously reported techniques were employed to quantitatively elucidate the parameters regarding lumbar morphology and identical pedicle orientation at each vertebra. The parameters for pedicle angle (PA), pedicle diameter (PD), pedicle axis distance (PAD), midline axis distance (MAD), transverse pedicle axis distance (TPAD) and transverse intertangential angle (TITA) were measured.
RESULTS: Taiwanese subjects had different PA, PD, PAD, MAD at L1 to L5 and TITA at L3 to L5 compared with Caucasian subjects. L5 had the most convergent pedicle axis, the widest PD and the shortest antero-posterior axis morphology.
CONCLUSIONS: This study provides detailed information for identifying pedicle orientation during pedicle screw placement and elucidate racial differences in lumbar morphology and pedicle orientation between Taiwanese and Caucasian populations.

BACKGROUND: Oblique lateral interbody fusion (OLIF) surgery provides a convenient and minimal access to the lesion disc with few complications; however, the left lumbar sympathetic trunk (LST) lies in the surgical field with a certain incidence of injury. The aim of this study was to describe the anatomic structures of the left LST at risk for injury during OLIF at different lumbar segment levels based on radiologic evaluations.
METHODS: Forty-four healthy young people (22 men and 22 women) were recruited, and routine lumbar magnetic resonance radiograph was performed. The LST, abdominal aorta (AA), and psoas muscle (PM) were observed, and all parameters were acquired using axial T2-weighted turbo spin echo sequence images. Independent-samples t test, 1-way analysis of variance test, and Least significant difference test were used to explore the LST\'s tract and the anatomic relationship with the adjacent anatomic landmarks at different levels.
RESULTS: The distance from the left lateral border of the AA to the anterior medial border of the left PM was significantly narrowing from the L2-3 to L4-5 segment levels (13.72 ± 3.00, 11.78 ± 2.69, and 9.18 ± 3.43 mm). The distance from the left lateral border of the AA to the left LST was also significantly decreased from the L2-3 to L4-5 segment levels (11.14 ± 2.89, 9.36 ± 2.79, and 6.63 ± 2.94 mm). However, the distance from the leading edge of the left PM to the left LST had no statistical differences among all adjacent segment levels (2.96 ± 0.62, 2.83 ± 0.62, and 3.07 ± 0.86 mm). The location of the left LST is more backward and lateral at level L2-3, whereas it is inside front at levels L3-4 and L4-5.
CONCLUSIONS: The practical risk of LST injury in different segment levels varied with specific anatomic conditions. The segment level L2-3 could provide a safer surgical space for OLIF, and the risk of the left LST injury might be greater during OLIF at level L4-5.

BACKGROUND: S1-AI technique may be used as a salvage technique in pelvic fixation of complex spinal deformity surgery. However, the proper detailed parameters in the Chinese population has not been analyzed before to instruct S1-AI screws placement and to ensure the safety of clinical application while the trajectory in pelvic changes significantly at each angle.
RESULTS: The ideal S1AI screw trajectory could be obtained in 28 of 30 female patient images (93.3%) and in all of the male patient images (100%). The screws that have already been used clinically in S2AI pathways can be applied in S1AI fixations.
CONCLUSIONS: It is feasible to place S1AI screws in 93.3% of female Chinese adult patients and in all male Chinese patients. Preoperative CT reconstruction should be performed to evaluate proper trajectory parameters and to avoid anterior violation.

OBJECTIVE: To determine the importance of adequate preoperative assessment with color Doppler sonography to assist in the successful transfer of lateral upper arm flaps by studying the lateral upper arm flap with color Doppler sonography and analyzing the anatomic features of the radial collateral artery.
METHODS: A clinical case-control study was performed. The radial collateral artery was studied with color Doppler sonography in 15 healthy volunteers. The origins, courses, variations, and locations of the perforators of the radial collateral artery were recorded. The results and data from the color Doppler sonographic investigation were compared with an anatomic study that was performed on 22 adult cadaveric upper limb specimens.
RESULTS: The volunteer group (14 of 15 volunteers) and the cadaveric group (19 of 22 upper arm specimens) clearly showed that the branch pattern of the arterial supply was as follows: brachial artery → deep brachial artery → radial collateral artery → posterior radial collateral artery → myocutaneous perforator. Variations in the origin of the radial collateral artery were identified in 1 volunteer bilaterally and in 3 upper arm specimens. The diameters of the artery and vein measured at the distal insertion of the deltoid and the origin of the deep brachial artery were not significantly different between the volunteer and cadaver groups (P > .05). Due to the difference in measuring methods, the length of the vascular pedicles was significantly different between the groups (P < .05).
CONCLUSIONS: Color Doppler sonography can facilitate the preoperative assessment of the origin, course, variations, and locations of the radial collateral artery and therefore may increase the success rate of lateral upper arm flap transfer.