Inter-ischial spine distance is a simple index of narrow pelvis that may predict difficulty during laparoscopic low anterior resection: a retrospective study

Background A narrow pelvis makes laparoscopic rectal resection difficult. This study aimed to evaluate whether a simple measurement on computed tomography can predict procedural difficulty. Methods A total of 62 patients with low rectal cancer underwent conventional laparoscopic low anterior resection. The inter-ischial spine (IS) distance (i.e., distance between the ischial spines) was measured on an axial computed tomography slice. Operative time, blood loss, and time from insertion of linear staplers to completion of clamping on the distal end of the rectum (clamp time) were compared. Results Overall, 42 men and 20 women with low rectal cancer were assessed. The mean tumor size was 34.5 mm. Total or tumor-specific mesorectal excisions were performed in all cases; high ligation and resection of the inferior mesenteric arteries were carried out in 92% of patients. The mean operative time, and blood loss were 206 min, and 15 mL respectively. Four patients (6.5%) experienced postoperative complications, including two anastomotic leaks (3.2%). The mean IS distance was 93.3 mm. With simple linear regression, shorter IS distance correlated with longer operative time (R2 = 0.08, P = 0.030) and clamp time (R2 = 0.07, P = 0.046). Using an receiver operating characteristic curve, a narrow pelvis was defined as IS distance < 94.7 mm. Multivariate regression analysis revealed that IS distance < 94.7 mm (odds ratio, 3.51; P = 0.04) was independently associated with a longer clamp time. Conclusions The IS distance is a simple and useful measurement for predicting the difficulty of laparoscopic low anterior resection.

Bony landmarks, distances and their correlations to each other, which can be used during periacetabular osteotomy: a CT study performed on dysplastic hips

As a surgical technique for hip dysplasia, Bernese periacetabular osteotomy (PAO) still poses technical difficulties and unclear surgical steps like the depth of the first ‘ischial’ cut, the start of the iliac cut and the width of the retroacetabular cut to prevent either iatrogenic joint entrance or posterior column fracture. Twenty-seven dysplastic hips (CE &lt; 25°) were randomly matched with nondysplastic hips (n: 27, CE &gt; 25°). 3D CT sections of the hips were evaluated and the width of the ischium, the distance from the infra-acetabular groove to the ischial spine, from the anterior superior iliac spine (ASIS) to the joint or sciatic notch or the sciatic spine, from the most medial point at the acetabulum to the posterior column, ischial spine or sciatic notch were measured for each group and correlated. The distances (mm) from the infra-acetabular groove to the ischial spine (42 ± 4, 44 ± 4, P: 0.03), the anterior superior iliac spine to the joint (52 ± 6, 60 ± 3, P: 0.03), the most medial point at the acetabulum to the posterior column (34 ± 2, 36 ± 2, P: 0.005) were shorter in the dysplastic group. The distance from the ASIS to the sciatic notch was correlated with the distance from the infra-acetabular groove to the ischial spine, from the ASIS to the joint and the most medial point at the acetabulum to the posterior column. The distance from the ASIS to the sciatic notch can be used intraoperatively to guess the X-ray guided or blindly osteotomized stages to predict the width or depth of the osteotomy to prevent intraarticular extension or posterior column fracture.

Anatomical Identification of Ischial Spines Applicable to Intrapartum Transperineal Ultrasound Based on Magnetic Resonance Imaging of Pregnant Women

Intrapartum transperineal ultrasound (ITU) is considered useful in judging fetal head descent; however, the inability to detect ischial spines on ITU has been a drawback to its legitimacy. The current study aimed to determine the anatomical location of ischial spines, which can be directly applied to ITU. Based on magnetic resonance imaging of 67 pregnant women at 33+ 2 [31+ 6-34+ 0] weeks gestation (median [interquartile range: IQR]), we calculated the angle between the pubic symphysis and the midpoint of ischial spines (midline symphysis-ischial spine angle; mSIA), which is theoretically equivalent to the angle of progression at fetal head station 0 on ITU, by determining spatial coordinates of pelvic landmarks and utilizing spatial vector analysis. Furthermore, we measured symphysis-ischial spine distance (SID), defined as the distance between the vertical plane passing the lower edge of the pubic symphysis and the plane that passes the ischial spines. As a result, mSIA was 109.6 ° [105.1–114.0] and SID 26.4 mm [19.8–30.7] (median, [IQR]). There was no correlation between mSIA or SID and maternal characteristics, including physique. Our results provide valuable evidence to enhance the reliability of ITU in assessing fetal head descent by considering the location of ischial spines.

Infra-acetabular screw exited between ischial tuberosity and ischial spine is more suitable for Asian population: a 3D morphometric study

Background Recently, the infra-acetabular screw has been proposed for use in treatment of acetabular fractures as a part of a periacetabular fixation frame. Biomechanical studies have shown that an additional infra-acetabular screw placement can enhance the fixation strength of acetabular fracture internal fixation. Currently, the reported exit point of the infra-acetabular screw has been located at the ischial tuberosity (Screw I). However, our significant experience in placement of the infra-acetabular screw has suggested that when the exit point is located between the ischial tuberosity and the ischial spine (Screw II), the placement of a 3.5 mm infra-acetabular screw may be easier for some patients. We conducted this study in order to determine the anatomical differences between the two different IACs. Methods The raw datasets were reconstructed into 3D models using the software MIMICS. Then, the models, in the STL format model, were imported into the software Geomagic Studio to delete the inner triangular patches. Additionally, the STL format image processed by Geomagic Studio was imported again into MIMICS. Finally, we used an axial perspective based on 3D models in order to study the anatomical parameters of the two infra-acetabular screw corridors with different exit points. Hence, we placed the largest diameter virtual screw in the two different screw corridors. The data obtained from this study presents the maximum diameter, length, direction, and distances between the entry point and center of IPE. Results In 65.31% males and 40.54% females, we found a screw I corridor with a diameter of at least 5 mm, while a screw II corridor was present in 77.55% in males and 62.16% in females. Compared to screw I, the length of screw II is reduced, the angle with the coronal plane is significantly reduced, and the angle with the transverse plane is significantly increased. Conclusions For East Asians, changing the exit point of the infra-acetabular screw can increase the scope of infra-acetabular screw use, especially for females.

Infra-acetabular screw exited between ischial tuberosity and ischial spine is more suitable for Asian population: A 3D Morphometric study

Background Recently, the infra-acetabular screw has been proposed for use in treatment of acetabular fractures as a part of a periacetabular fixation frame. Biomechanical studies have shown that an additional infra-acetabular screw placement can enhance the fixation strength of acetabular fracture internal fixation. Currently, the reported exit point of the infra-acetabular screw has been located at the ischial tuberosity (Screw I). However, our significant experience in placement of the infra-acetabular screw has suggested that when the exit point is located between the ischial tuberosity and the ischial spine (Screw II), the placement of a 3.5 mm infra-acetabular screw may be easier for some patients. We conducted this study in order to determine the anatomical differences between the two different IACs. Methods The raw datasets were reconstructed into 3D models using the software MIMICS. Then, the models, in the STL format model, were imported into the software Geomagic Studio to delete the inner triangular patches. Additionally, the STL format image processed by Geomagic Studio was imported again into MIMICS. Finally, we used an axial perspective based on 3D models in order to study the anatomical parameters of the two infra-acetabular screw corridors with different exit points. Hence, we placed the largest diameter virtual screw in the two different screw corridors. The data obtained from this study presents the maximum diameter, length, direction, and distances between the entry point and center of IPE. Results In 65.31% males and 40.54% females, we found a screw I corridor with a diameter of at least 5 mm, while a screw II corridor was present in 77.55% in males and 62.16% in females. Compared to screw I, the length of screw II is reduced, the angle with the coronal plane is significantly reduced, and the angle with the transverse plane is significantly increased.Conclusions For East Asians, changing the exit point of the infra-acetabular screw can increase the scope of infra-acetabular screw use, especially for females.

Infra-acetabular screw exited between ischial tuberosity and ischial spine is more suitable for Asian population: A 3D Morphometric study

Background Recently, the infra-acetabular screw has been proposed for use in treatment of acetabular fractures as a part of a periacetabular fixation frame. Biomechanical studies have shown that an additional infra-acetabular screw placement can enhance the fixation strength of acetabular fracture internal fixation. Currently, the reported exit point of the infra-acetabular screw has been located at the ischial tuberosity (Screw I). However, our significant experience in placement of the infra-acetabular screw has suggested that when the exit point is located between the ischial tuberosity and the ischial spine (Screw II), the placement of a 3.5 mm infra-acetabular screw may be easier for some patients. We conducted this study in order to determine the anatomical differences between the two different IACs. Methods The raw datasets were reconstructed into 3D models using the software MIMICS. Then, the models, in the STL format model, were imported into the software Geomagic Studio to delete the inner triangular patches. Additionally, the STL format image processed by Geomagic Studio was imported again into MIMICS. Finally, we used an axial perspective based on 3D models in order to study the anatomical parameters of the two infra-acetabular screw corridors with different exit points. Hence, we placed the largest diameter virtual screw in the two different screw corridors. The data obtained from this study presents the maximum diameter, length, direction, and distances between the entry point and center of IPE. Results In 65.31% males and 40.54% females, we found a screw I corridor with a diameter of at least 5 mm, while a screw II corridor was present in 77.55% in males and 62.16% in females. Compared to screw I, the length of screw II is reduced, the angle with the coronal plane is significantly reduced, and the angle with the transverse plane is significantly increased.Conclusions For East Asians, changing the exit point of the infra-acetabular screw can increase the scope of infra-acetabular screw use, especially for females.

Putative Clinical Implications of Unilateral Ossified Sacrospinous Ligament

Introduction Sacrospinous ligament (SSL) is a thin structure that extends from the ischial spine to the lateral margins of sacrum and coccyx, anterior to the Sacrotuberous ligament (STL). The internal pudendal and inferior gluteal vessels, pudendal nerve, sciatic nerve, and other branches of sacral nerve plexus pass through the greater sciatic foramen (GSF) in close proximity to the ischial spine and SSL. Objective This study aimed to report a case encountered during the routine osteology tutorial, where one of the pelvises presented with ossified SSL on the right side along with ossification of lumbosacral and the sacroiliac joints. Case Report The SSL of the right side of the pelvis was completely ossified, extending between the ischial spine and fifth piece of sacrum. The ossification had a broad-based origin from the sacrum and tapered as in proceeded to the ischial spine. It was attached to the ischial spine with a slight enlargement. Moreover, the lumbosacral and the sacroiliac joints also appeared to be ossified. Conclusion Ossification of the SSL can restrict the lesser sciatic foramen and the greater sciatic foramen, thus causing compression of neurovascular structures traversing these areas. This can be the causative factor in pudendal nerve/sciatic nerve entrapment and can be a cause for undiagnosed chronic perineal pain. Proper anatomical knowledge and radiologic studies can be utilized for accurate diagnosis and treatment of neurovascular compression syndromes and also during reconstructive procedures of the pelvic floor and treatment of uterovaginal prolapse.