Redefining the vascular anatomy of the medial gastrocnemius muscle: A computed tomography angiography study

BACKGROUND

The medial gastrocnemius (GN) muscle flap is a historical reconstructive option in lower limb reconstruction. The flap is proximally based on the medial sural artery, and it is assumed not possible to harvest a distally based flap because of the absence of other minor pedicles. The aim of this study is to investigate the presence and the anatomy of a distal secondary pedicle given off by the posterior tibial artery (PTA).

METHODS

A retrospective CTA study was performed of 120 limbs between April 2018 and June 2020. 3D reconstruction was performed to delineate the anatomy of the distal secondary pedicle, if present. The distance of the pedicle, if found, from the intermalleolar line to the patella was noted. The number of pedicles, if multiple, was documented, as well as branches to the soleus muscle and the skin.

RESULTS

A distal pedicle to the gastrocnemius muscle was found in 64% of limbs. The average location from the intermalleolar line is 168 mm. The branching pattern from the PTA showed an isolated vessel going to the distal medial gastrocnemius (32.8%), two branches to the medial gastrocnemius and skin (39.3%), two branches to the medial gastrocnemius and soleus (24.6%), and three branches to the medial gastrocnemius, soleus, and the skin (3.3%).

CONCLUSIONS

This study confirms the presence of the secondary axial distal pedicle of the GN muscle. Furthermore, this study confirms that there is a likely association between the distal medial gastrocnemius pedicle and the PTA skin perforators.

Surgical Landmarks for Parapharyngeal Internal Carotid Artery During Extended Endoscopic Surgery of Nasopharynx: A Cadaveric and Radiological Study

Nasopharynx is a complex region situated at the center of skull surrounded by various vital neurovascular structures. Surgical access to the nasopharyngeal space poses significant challenges due to the position of the internal carotid artery (ICA). Open approaches to nasopharynx utilize the lateral to medial anatomy but the endoscopic endo-nasal approach warrants knowledge about the medial to lateral anatomy. In this study we attempted to find the consistent surgical landmarks for parapharyngeal portion of internal carotid artery at the level of nasopharynx by means of cadaveric and radiological study. Eight fresh frozen cadavers (16 sides) and 30 CT angiography (60 sides) were included in the anatomical and radiological study respectively. Superior aspect of the torus tubarius was taken as the reference point in cadaveric study and C1-C2 interspace was used as the reference point for the radiological study. The distance between the ICA to the landmarks such as fossa of Rosenmullaer, torus tubarius, medial and lateral pterygoid plates were recorded. The mean distance of ICA to the fossa of Rosenmuller was 8.5 ± 1.4 mm and 9.1 ± 1.1 mm in the cadaveric and radiological study respectively. The mean distance between ICA to torus tubarius was 19.8 ± 1.3 mm in cadaveric and 20.6 ± 1.0 mm in radiological study. The mean distance of ICA to medial and lateral pterygoid plates were 25.3 ± 1.4 mm and 18.2 ± 1.4 mm in the cadaveric study and 25.9 ± 1.2 mm and 18.8 ± 1.3 mm in the radiological study respectively. On correlating the measurements between cadaveric and radiological study, the p values were not statistically significant (p > 0.05). The closest landmark to the ICA was the fossa of Rosenmuller. ICA was located at the same sagittal plane as that of the lateral pterygoid plate. The nasopharynx is a complex anatomical region closely related to ICA. Inadvertent injury to ICA is one of the dreaded complications of nasopharyngeal surgery. Fossa of Rosenmuller is only few millimeters away from the ICA and must be treated very cautiously. During the endoscopic approach, the ICA is at the sagittal plane as of the lateral pterygoid plate. This must be kept in mind when advancing toward the ICA by keeping intact the lateral pterygoid plate when possible and one should stay in the plane of medial pterygoid plate as the ICA lies posterolateral to it. Cadaveric dissections supported by radiological data would definitely aid surgeons to successfully perform surgeries in nasopharynx.

Variations in the shape of foramen magnum at the base of human skulls among Indians in Rajasthan

Variations in the shape of foramen magnum can affect the normal anatomy of vital structures passing through it. Therefore, it is of interest to evaluate the various shapes of foramen magnum by using CT scans performed in patients of Indian population to establish clinical correlation. A total of 314 CT images of human skull base obtained from the Department of Radio-diagnosis, Geetanjali Medical College and Hospital, Udaipur, Rajasthan were used in the present study. All the patients' CT scans were observed to determine the shape of foramen magnum. They were classified into one of the following shapes: Oval, round, tetragonal, egg shaped, hexagonal, pentagonal and irregular. The shapes of the foramen magnum in CT scans were oval in 39.09%, round in 22.61%, tetragonal in 12.10%, hexagonal in 10.51%, irregular in 7.96%, pentagonal in 5.41% and egg shaped in 1.59% CT images. Data shows that it is easy to operate at the base of skull in case of round, oval and hexagonal shape foramen magnum, as the working space is more in these shapes.

The proximal vastus lateralis flap: An anatomical and radiological study

INTRODUCTION

Soft-tissue reconstruction following acetabular or proximal femur resection for bone tumors is challenging. The vastus lateralis flap has been proposed as an advancement or rotational flap to cover soft-tissue defects for such locoregional indications. We performed an anatomical and a radiological study to assess the vascularization of the proximal vastus lateralis muscle achieved through the transverse branch of the lateral circumflex femoral artery in order to decrease the morbidity of the classical flap retrieval technique.

MATERIAL AND METHODS

Five fresh adult cadavers were dissected bilaterally. Each vastus lateralis dissection was prealably injected with contrast-media agent through the lateral circumflex artery and CT scan images was recorded. A descriptive and an analytical study were carried out.

RESULTS

The median length and width of the entire muscle were 31.2cm (Q1-Q3: 29.7-33.3) and 12.7cm (Q1-Q3: 7.0-14.9), respectively; the median surface area of the entire vastus lateralis muscle was 282cm² (Q1-Q3: 172.6-455.6) cm². The median length and width of the perfused area were 13.3cm (Q1-Q3: 12.3-16.6) and 9.4cm (Q1-Q3: 6.9-8.8) cm, respectively; the median surface of the perfused area was 89.4cm² (Q1-Q3: 67.4-110.5) cm². The mean length of the pedicle measured on the CT scan was 6.3cm (95% CI: 5.5-7.1).

CONCLUSION

The proximal vastus lateralis flap as a pedicled muscular flap supplied by the transverse branch of the lateral circumflex femoral artery is a muscular flap that can be used by reconstructive and orthopaedic surgeons to repair soft-tissue defects around the hip joint without undue damage to the functional apparatus of the knee.

Surgical Indications in Hypophosphataemic Rickets

Low levels of phosphate in blood secondary to a lack of phosphorous reabsorption in the renal tubule cause hypophosphataemic rickets. To increase blood calcium levels, bone calcium is released into the bloodstream by increasing the activity of osteoclasts in the bones. These alterations in bone metabolism lead to delayed growth and small height, diffuse bone pain, bone fragility with microfractures, and frequent fractures and bone deformities. Although management of some of these conditions is mainly conservative, in cases of bone deformities or severe osteomalacia surgery should be considered: from minimally invasive surgical techniques of guided growth in patients with less deformity and open physeal cartilage to correction osteotomies in three-dimensional deformities. This article briefly reviews the indications for surgery procedures to be performed in these patients, highlighting when to use aggressive and non-aggressive approaches.

Differences in bone mineral density of trajectory between lumbar cortical and traditional pedicle screws

BACKGROUND

Cortical bone trajectory (CBT) has been well-known in spine surgery for obtaining improved fixation while minimizing soft tissue dissection. This study was designed to compare the bone mineral density (BMD) between the CBT and traditional trajectory (TT) by using Hounsfield unit (HU) values and identify the ideal decades of patients and the suitable lumbar segments using this CBT technology from a radiological standpoint.

METHODS

Patients were selected randomly from an institutional database based on age (evenly distributed by a decade of life) and gender. A total of 240 healthy patients had a computed tomography (CT) scan of the chest, abdomen, and pelvis. For each patient, axial slices of every vertebra were cut in two planes: one horizontal to the pedicle representing the plane wherein pedicle screws were inserted using the TT and the other in a caudocranial plane representing the plane wherein pedicle screws were inserted using the CBT. For each trajectory, a region of interest (ROI) was selected within the area wherein the screws were inserted. A CT number (HU values) was then calculated within each ROI to represent bone density.

RESULTS

HU values measured at the ROI of CBT were significantly greater than those of the traditional pedicle screw in all age groups, and the specific value (ratio of the HU values of CBT/the HU values of TT) between CBT and TT was 1.92. A significant difference was observed between male and female. The HU values of CBT and TT of males were generally higher than those of females (males: CBT/TT 1.89 ± 0.45; Females: CBT/TT 1.95 ± 0.47). The specific value in HU values significantly increased with increasing age (p = 0.000) and cauda lumbar level (p = 0.000) in males and females.

CONCLUSION

BMD, as measured by HU values for the ROI of the CBT screw, was significantly greater than that of the traditional pedicle screw, especially in old patients and cauda lumbar segments.

A cadaveric and sonographic study of the morphology of the tibialis anterior tendon - a proposal for a new classification

Background

The tibialis anterior tendon (TAT) presents little morphological variation. The tibialis anterior muscle originates at the lateral condyle of the tibia, the proximal one-third to two-thirds of the lateral surface of the tibia shaft, and the anterior surface of the interosseous membrane and inserts to the medial cuneiform bone and first metatarsal. The aim of our work is to classify types of TAT insertion by two complimentary methods - anatomical dissection and ultrasound examination.

Methods

In the first part, classical anatomical dissection was performed on 100 lower limbs (50 right, 50 left) fixed in 10% formalin solution. The morphology of the insertion of the tendon was evaluated and the muscle was subjected to the appropriate morphometric measurements. In the second part, the morphology of the TAT insertion was evaluated in 50 volunteers with ultrasound.

Results

The tibialis anterior muscle was present in all specimens. In the cadavers, five types of insertion were observed, the most common being Type V: a single band attaching to the medial cuneiform bone (32%). In the sonographic part, Type IV was not observed; however, an additional insertion type was recognised (Type VI), which was characterized by two identical bands attached only to the medial cuneiform bone. The most common type identified by ultrasound was Type II (35%).

Conclusion

The tibialis anterior tendon presents high morphological variability that can be observed both in cadavers and in vivo by ultrasound examination.

Level of evidence

II Prospective Comparative Study

Electronic supplementary material

The online version of this article (10.1186/s13047-019-0319-0) contains supplementary material, which is available to authorized users.

Infection by Streptococcus pneumoniae in children with or without radiologically confirmed pneumonia

OBJECTIVE

Community-acquired pneumonia is an important cause of morbidity in childhood, but the detection of its causative agent remains a diagnostic challenge. The authors aimed to evaluate the role of the chest radiograph to identify cases of community-aquired pneumonia caused by typical bacteria.

METHODS

The frequency of infection by Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis was compared in non-hospitalized children with clinical diagnosis of community acquired pneumonia aged 2-59 months with or without radiological confirmation (n=249 and 366, respectively). Infection by S. pneumoniae was diagnosed by the detection of a serological response against at least one of eight pneumococcal proteins (defined as an increase ≥2-fold in the IgG levels against Ply, CbpA, PspA1 and PspA2, PhtD, StkP-C, and PcsB-N, or an increase ≥1.5-fold against PcpA). Infection by H. influenzae and M. catarrhalis was defined as an increase ≥2-fold on the levels of microbe-specific IgG.

RESULTS

Children with radiologically confirmed pneumonia had higher rates of infection by S. pneumoniae. The presence of pneumococcal infection increased the odds of having radiologically confirmed pneumonia by 2.8 times (95% CI: 1.8-4.3). The negative predictive value of the normal chest radiograph for infection by S. pneumoniae was 86.3% (95% CI: 82.4-89.7%). There was no difference on the rates of infection by H. influenzae and M. catarrhalis between children with community-acquired pneumonia with and without radiological confirmation.

CONCLUSIONS

Among children with clinical diagnosis of community-acquired pneumonia submitted to chest radiograph, those with radiologically confirmed pneumonia present a higher rate of infection by S. pneumoniae when compared with those with a normal chest radiograph.

A novel diagnostic parameter, foraminal stenotic ratio using three-dimensional magnetic resonance imaging, as a discriminator for surgery in symptomatic lumbar foraminal stenosis

BACKGROUND CONTEXT

No previous studies have reported the radiological features of patients requiring surgery in symptomatic lumbar foraminal stenosis (LFS).

PURPOSE

This study aims to investigate the diagnostic accuracy of a novel technique, foraminal stenotic ratio (FSR), using three-dimensional magnetic resonance imaging for LFS at L5-S by comparing patients requiring surgery, patients with successful conservative treatment, and asymptomatic patients.

STUDY DESIGN

This is a retrospective radiological comparative study.

PATIENT SAMPLE

We assessed the magnetic resonance imaging (MRI) results of 84 patients (168 L5-S foramina) aged ≥40 years without L4-L5 lumbar spinal stenosis. The foramina were divided into three groups following standardized treatment: stenosis requiring surgery (20 foramina), stenosis with successful conservative treatment (26 foramina), and asymptomatic stenotic foramen (122 foramina).

OUTCOME MEASURES

Foraminal stenotic ratio was defined as the ratio of the length of the stenosis to the length of the foramen on the reconstructed oblique coronal image, referring to perineural fat obliterations in whole oblique sagittal images. We also evaluated the foraminal nerve angle and the minimum nerve diameter on reconstructed images, and the Lee classification on conventional T1 images.

MATERIALS AND METHODS

The differences in each MRI parameter between the groups were investigated. To predict which patients require surgery, receiver operating characteristic (ROC) curves were plotted after calculating the area under the ROC curve.

RESULTS

The FSR showed a stepwise increase when comparing asymptomatic, conservative, and surgical groups (mean, 8.6%, 38.5%, 54.9%, respectively). Only FSR was significantly different between the surgical and conservative groups (p=.002), whereas all parameters were significantly different comparing the symptomatic and asymptomatic groups. The ROC curve showed that the area under the curve for FSR was 0.742, and the optimal cutoff value for FSR for predicting a surgical requirement in symptomatic patients was 50% (sensitivity, 75%; specificity, 80.7%).

CONCLUSIONS

The FSR determined LFS requiring surgery among symptomatic patients, with moderate accuracy. Foramina occupied ≥50% by fat obliteration were likely to fail conservative treatment, with a positive predictive value of 75%.

The feasibility and radiological features of sacral alar iliac fixation in an adult population: a 3D imaging study

BACKGROUND

Surgical treatments for adult spinal deformities often include pelvic fixation, and the feasibility of sacral-2 alar iliac (S2AI) screw fixation has been shown previously. However, sometimes S2AI screw fixation cannot be applied due to the presence of an osteolytic lesion or trauma or because the biomechanical properties of only an S2AI screw is insufficient. Therefore, we questioned the feasibility of using sacral AI screws in other segments and determined whether S3AI and S4AI screws have the potential to be used for sacral fractures. The aim of this study was to investigate the feasibility and radiological features of sacral AI fixation in S1-S4 in an adult population using 3D imaging techniques.

METHODS

Computed tomography (CT) scans were taken of 45 patients and were imported into Mimics (Version 10.01, Materialise, Belgium) software to reconstruct the 3D digital images. Next, a cylinder (radius of 3.5 mm) was drawn to imitate the screw trajectory of a S1-4 AI screw, and every imitated screw in each segment was adjusted to a maximum upward and downward angle to acquire the feasible region. The parameters of the S1-4AI screw trajectories were measured.

RESULTS

Sacral AI screws could be successfully imitated using 3D digital imaging. The S4AI screw trajectory could be obtained in 19 of 45 patient images (42.2%), while the feasibility rates of S1AI, S2AI, and S3AI screw fixation were 100%, 100%, and 91.1% (41/45), respectively. The feasible regions of S1AI, S2AI, and S3AI screw trajectories were wide enough, while the adjustable angle of S4AI screws was very small.

CONCLUSION

It is feasible to place S1-2AI screws in the entire adult population and S3-4AI screws in some of the adult population. Furthermore, our study suggested that 3D digital images are suitable to study the feasibility of new screw fixation.