Intermuscular Space Research Articles

Giant mucinous liposarcoma of the abdominal cavity: A case report.

Mucinous liposarcoma myxoid liposarcoma is a malignant mucoid soft tissue tumor derived from undifferentiated stromal cells in perivascular, subbody cavity and intermuscular space, and composed of cells at different stages of differentiation from preadipocytes to mature cells. In rare cases, it may change from lipoma malignancy. The main manifestations is painless mass, relatively slow growth, the course can last decades, the prevalence of liposarcoma in the population is 14% to 18%, mainly in adults, male prevalence is higher than women, but not significant. The main good hair part is the thigh, have mucinous sex, high differentiation type, dedifferentiation type, polymorphic type. Clinical diagnosis is difficult, and there are no obvious symptoms in the early stage, so the diagnosis should be combined with B ultrasound, MRI, CT, and other auxiliary examinations. The gold standard is pathological examination. In December 2023, our department admitted a patient with a mucinous abdominal mass. The report is as follows. Does liposarcoma metastasize? Is any chemotherapy required after surgery? Will it ever relapse in the future? What is the survival period after surgery? Mucinous liposarcoma. Surgical resection of the sarcoma. The nodule sample was 33 * 28 * 13 cm, with complete capsule, gray and yellow sections, fine texture, soft, gray, red, grayish, and yellow mucoid nodules in some areas, and the maximum diameter of the nodules was 21cm. Immunohistochemistry was: CD34 (+), CDK 4 (+), CK (-), Desmin (weak +), Ki67 (index 5%), MDM 2 (-), p16 (weak +), S-100P (+), Vimentin (+), BCL-2 (+). He was also sent to the Department of Pathology of Peking Union Medical College Hospital for consultation with Professor Lu Zhaohui, whose consultation opinion was in line with myxoliposarcoma. Retroperitoneal liposarcoma is a common retroperitoneal tumor, but it is relatively rare in clinical practice; the overall morbidity is low, mainly manifested as abdominal pain and abdominal distension, abdominal distension, and a long course of disease; it is not sensitive to radiotherapy and chemotherapy, and should be closely follow up by CT examination to understand the recurrence and metastasis.

Endoscopic intermuscular dissection (EID) for removing early rectal cancers and benign fibrotic rectal lesions.

In the current era of screening colonoscopy and increasing incidence of early rectal cancer, interventional endoscopy moves toward resections in deeper planes than the submucosal layer. Several reports support the use of endoscopic intermuscular dissection (EID) instead of endoscopic submucosal dissection (ESD) for the removal of deeply invasive rectal submucosal cancers. The resection plane into the intermuscular space, the space between the longitudinal (external) and circular (internal) muscle layer, allows radical removal of rectal invasive submucosal cancers. Furthermore, the technique offers the potential for dissection of scarred and severe fibrotic lesions in the rectum by cutting deeper and performing a partial myectomy avoiding the narrow submucosal space. We present 23 cases ofEIDs both for deeply invasive rectal cancers and benign rectal lesions. This is the first report in the literature of EID resections for malignant and benign disease, including cases of severely fibrotic rectal lesions.

Histological and morphometric analysis of skeletal muscle in some vertebrates

The skeletal system is primarily driven by the skeletal muscles to produce kinematic movements. The study evaluates the histological and morphometric properties of skeletal muscle in Clarias gariepenus (Cl. gariepinus), Bufo bufo (B. bufo), Agama agama (A. agama), Columba livia domestica (C. domestica) and Rattus rattus (R. rattus). The study was carried in order to relate the similarities and differences of skeletal muscles in these species with evolutionary trend. The epaxial muscle of Cl. Gariepinus, the biceps femoris muscle of B. bufo, R. rattus, puboischiotibialis of A. agama, and pectoral muscle from C. domestica were removed and assessed grossly for physical appearance then processed for histological analysis. The diameters of the muscle fibers were measured and one-way analysis of variance was used to compare the differences. The muscles of Cl. gariepinus, B. bufo and A. agama appeared whitish with scanty fusiform nucleus and large intermuscular space. However, the muscles of C. domestica and R. rattus appeared red with distinct round nucleus and small intermuscular space. No significant difference (P>0.05) was observed in the muscle diameter of Cl. gariepinus (8.86±0.13µm) compared to B. bufo (8.25±0.27µm). The muscle diameter of A. agama (10.18±0.25µm) was significantly higher (P<0.05) relative to Cl. gariepinus (8.86±0.13µm), B. bufo (8.25±0.27µm), C. domestica (3.38±0.13µm) and R. rattus (4.66±0.15µm). Conclusively, non-tetrapod vertebrates (Cl. gariepinus, B. bufo, and A. agama) have simple, white-colored skeletal muscle with few flat-shaped nuclei and large fiber diameters while higher vertebrates (C. domestica and R. rattus) have complex, red-colored skeletal muscle with numerous oval-shaped nucleus and small fiber diameter.

A Randomized Comparison between Classical Landmark-based and Ultrasound-guided Right Superficial Cervical Plexus Block in Attenuating Postlaparoscopic Shoulder Pain under Subarachnoid Anesthesia

ABSTRACT Background: Postlaparoscopic shoulder pain is believed to be due to phrenic nerve involvement, with an incidence of 35%–80%. Classical landmark-based right superficial cervical plexus block (SCPB) has been utilized to alleviate postlaparoscopic shoulder pain. However, there is no possibility of phrenic nerve blockade with subcutaneously deposited injectate in landmark-based SCPB. Therefore, we hypothesized that the local anesthetic injectate in the sternocleidomastoid-scalene intermuscular fascial plane under ultrasound guidance is paramount in achieving phrenic nerve blockade. The main objective was to evaluate the effect of ultrasound-guided right SCPB in decreasing postlaparoscopic shoulder pain compared to conventional landmark-guided SCPB. Methods: In this prospective randomized trial, 79 adult patients reported for laparoscopic surgeries under spinal anesthesia were randomly divided into groups; A and B. Group A patients received intermediate approach to SCPB with 10 ml of 0.5% bupivacaine under ultrasound guidance. Group B patients received SCPB using a classical landmark-based approach. The incidence of intraoperative and postoperative shoulder pain and other adverse effects were noted. Results: Intraoperative shoulder pain was significantly less in Group A than in Group B (5% vs. 43.5%, P < 0.001). The postoperative shoulder pain was also significantly reduced in Group A than in Group B (5% vs. 28.2%, P = 0.013). There were no instances of major adverse effects. Conclusion: We conclude that the ultrasound-guided injectate in the sternocleidomastoid-scalene intermuscular space deeper to investing layer but superficial to the prevertebral layer of the deep cervical fascia is central to providing superior shoulder pain relief in patients undergoing laparoscopic surgery under spinal anesthesia than the classical landmark-based SCPB.

The anatomic study and surgical technique for canal decompression with “pedicle-plasty” strategy in lumbar burst fractures with pedicle rupture

ABSTRACT In the treatment of lumbar burst fractures with nerve injury, fusion is often required to rebuild spinal stability, but it can lead to the loss of motor units and increase the occurrence of adjacent segment diseases. Thus, a novel approach of lumbar canal decompression with “pedicle-plasty” strategy (DDP) was needed in clincal treatment. Firstly, image measurement analysis, the images of 60 patients with lumbar spine CT examinations were selected to measure osteotomy angle (OA), distance from the intersection of osteotomy plane and skin to the posterior midline (DM),transverse length of the osteotomy plane (TLOP), and sagittal diameter of the outer edge of superior articular process (SD). Secondary, cadaver study, distance between the intermuscular space and midline (DMSM), anterior and posterior diameters of the decompression (APDD), and lateral traction distance of the lumbosacral plexus (TDLP) were measured on 10 cadaveric specimens. Finally, procedure of DDP was demonstrated on cadaver specimens. OA ranged from 27.68°+4.59° to 38.34°+5.97°, DM ranged from 43.44+6.29 to 68.33+12.06 mm, TLOP ranged from 16.84+2.19 to 19.64+2.36 mm, and SD ranged from 22.49+1.74 to 25.53+2.21 mm. DMSM ranged from 45.53+5.73 to 65.46+6.43 mm. APDD were between 10.51+3.59 and 12.12+4.54 mm, and TDLP were between 3.28+0.81 and 6.27+0.62 mm.DDP was successfully performed on cadaveric specimens. DDP, as a novel approach of decompression of burst fractures with pedicle rupture, can fully relieve the occupation and at the same time preserve the spinal motor unit because of no resection of intervertebral discs and no destruction of facet joints,and has certain developmental significance.

Preparation and bone repair capability of a new plastic bone filler material

To prepare a new plastic bone filler material with adhesive carrier and matrix particles derived from human bone, and evaluate its safety and osteoinductive ability through animal tests. The human long bones donated voluntarily were prepared into decalcified bone matrix (DBM) by crushing, cleaning, and demineralization, and then the DBM was prepared into bone matrix gelatin (BMG) by warm bath method, and the BMG and DBM were mixed to prepare the experimental group's plastic bone filler material; DBM was used as control group. Fifteen healthy male thymus-free nude mice aged 6-9 weeks were used to prepare intermuscular space between gluteus medius and gluteus maximus muscles, and all of them were implanted with experimental group materials. The animals were sacrificed at 1, 4, and 6 weeks after operation, and the ectopic osteogenic effect was evaluated by HE staining. Eight 9-month-old Japanese large-ear rabbits were selected to prepare 6-mm-diameter defects at the condyles of both hind legs, and the left and right sides were filled with the materials of the experimental group and the control group respectively. The animals were sacrificed at 12 and 26 weeks after operation, and the effect of bone defect repair were evaluated by Micro-CT and HE staining. In ectopic osteogenesis experiment, HE staining showed that a large number of chondrocytes could be observed at 1 week after operation, and obvious newly formed cartilage tissue could be observed at 4 and 6 weeks after operation. For the rabbit condyle bone filling experiment, HE staining showed that at 12 weeks after operation, part of the materials were absorbed, and new cartilage could be observed in both experimental and control groups; at 26 weeks after operation, the most of the materials were absorbed, and large amount of new bone could be observed in the 2 groups, while new bone unit structure could be observed in the experimental group. Micro-CT observation showed that the bone formation rate and area of the experimental group were better than those of the control group. The measurement of bone morphometric parameters showed that the parameters at 26 weeks after operation in both groups were significantly higher than those at 12 weeks after operation ( P<0.05). At 12 weeks after operation, the bone mineral density and bone volume fraction in the experimental group were significantly higher than those in the control group ( P<0.05), and there was no significant difference between the two groups in trabecular thickness ( P>0.05). At 26 weeks after operation, the bone mineral density of the experimental group was significantly higher than that of the control group ( P<0.05). There was no significant difference in bone volume fraction and trabecular thickness between the two groups ( P>0.05). The new plastic bone filler material is an excellent bone filler material with good biosafety and osteoinductive activity.

Intermuscular technique for implantation of the subcutaneous implantable defibrillator: a propensity-matched case-control study.

A previous randomized study demonstrated that the subcutaneous implantable cardioverter defibrillator (S-ICD) was noninferior to transvenous ICD with respect to device-related complications and inappropriate shocks. However, that was performed prior to the widespread adoption of pulse generator implantation in the intermuscular (IM) space instead of the traditional subcutaneous (SC) pocket. The aim of this analysis was to compare survival from device-related complications and inappropriate shocks between patients who underwent S-ICD implantation with the generator positioned in an IM position in comparison with an SC pocket. We analysed 1577 consecutive patients who had undergone S-ICD implantation from 2013 to 2021 and were followed up until December 2021. Subcutaneous patients (n = 290) were propensity matched with patients of the IM group (n = 290), and their outcomes were compared. : During a median follow-up of 28 months, device-related complications were reported in 28 (4.8%) patients and inappropriate shocks were reported in 37 (6.4%) patients. The risk of complication was lower in the matched IM group than in the SC group [hazard ratio 0.41, 95% confidence interval (CI) 0.17-0.99, P = 0.041], as well as the composite of complications and inappropriate shocks (hazard ratio 0.50, 95% CI 0.30-0.86, P = 0.013). The risk of appropriate shocks was similar between groups (hazard ratio 0.90, 95% CI 0.50-1.61, P = 0.721). There was no significant interaction between generator positioning and variables such as gender, age, body mass index, and ejection fraction. Our data showed the superiority of the IM S-ICD generator positioning in reducing device-related complications and inappropriate shocks. Clinical Trial Registration: ClinicalTrials.gov; NCT02275637.

ASO Visual Abstract: Prognostic Significance and Management of Sentinel Nodes in the Triangular Intermuscular Space of Patients with Melanoma.

ASO Visual Abstract: Prognostic Significance and Management of Sentinel Nodes in the Triangular Intermuscular Space of Patients with Melanoma.

Prognostic Significance and Management of Sentinel Nodes in the Triangular Intermuscular Space of Patients with Melanoma.

The clinical significance of sentinel nodes (SNs) in the triangular intermuscular space (TIS) of patients with melanoma is poorly understood. This study aimed to determine their incidence and positivity rate, and to report their management and patient outcomes. This was a single-institution retrospective cohort study of patients with unilateral or bilateral TIS SNs on lymphoscintigraphy treated between 1992 and 2017. Recurrence-free survival was analyzed. Lymphoscintigraphy identified TIS SNs in 266 patients. They were bilateral in 17 patients. Of the 2296 patients with a melanoma on the upper back, 259 (11%) had TIS SNs. Procurement of SNs was not attempted in 122 (43%) of the 283 cases and failed in 11 cases (7%). An SN was successfully retrieved from the TIS in 145 patients (53%) and contained metastasis in 18 of 150 TIS SNs. This was the only positive SN in 12 patients (8%), upstaging all of them. Of the 18 patients with a positive SN in the TIS, 9 (50%) underwent completion axillary lymph node dissection, but no additional involved nodes were found in any of these patients. Recurrence in the TIS was observed in six patients (5%), none of whom had their TIS SN surgically pursued previously. Lymphoscintigraphy showed TIS SNs in 11% of patients with melanomas on their upper back. In such cases, retrieval of TIS SNs is required for accurate staging and to minimize the risk of TIS recurrence.

Intermuscular technique for implantation of the subcutaneous implantable defibrillator: a propensity-matched case-control study

Abstract Background A previous randomized study (PRAETORIAN) demonstrated that the subcutaneous implantable cardioverter–defibrillator (S-ICD) was noninferior to transvenous ICD with respect to device-related complications and inappropriate shocks. However, that was performed prior to the widespread adoption of pulse generator implantation in the intermuscular (IM) space instead of the traditional subcutaneous (SC) pocket. Purpose To compare survival from device-related complications and inappropriate shocks between patients who underwent S-ICD implantation with the generator positioned in an IM position in comparison with a SC pocket. Methods We analyzed 1577 consecutive patients who had undergone S-ICD implantation from 2013 to 2021 and were followed up until December 2021. SC patients were propensity-matched with patients of the IM group, and their outcomes were compared. Results SC implantations were performed in 367 (23%) patients. These patients were propensity-matched with 367 IM patients. Intra-procedural complications were reported in 9 (2.5%) patients in the SC Group and 7 (1.9%) in the IM Group. During a median follow-up of 29 months, device-related complications were reported in 55 (7.5%) patients and inappropriate shocks were reported in 54 (7.4%) patients. The risk of the composite primary endpoint was lower in the matched IM Group than in the SC Group (unadjusted hazard ratio 0.67, 95% CI 0.45–0.99, p=0.042), while the risk of appropriate shocks was similar between groups (unadjusted hazard ratio 0.99, 95% CI 0.60–1.64, p=0.976). There was no significant interaction between generator positioning and variables such as gender, age, body mass index, ejection fraction and generation of the device. Conclusions In this experience, IM S-ICD generator positioning was superior to SC positioning in reducing device-related complications and inappropriate shocks. Funding Acknowledgement Type of funding sources: None.

Lateral versus conventional fasciotomy for prevention of lateral femoral cutaneous nerve injury in total hip arthroplasty with direct anterior approach: a study protocol for a dual-center, double-blind, randomized controlled trial

BackgroundAn incision for total hip arthroplasty (THA) via the direct anterior approach (DAA) is generally made outside of the space between the sartorius and tensor fasciae latae muscles to prevent lateral femoral cutaneous nerve (LFCN) injury. Anatomical studies have revealed that the LFCN courses between the sartorius and tensor fasciae latae muscles. When the LFCN branches radially while distributing in the transverse direction from the sartorius muscle to the tensor fasciae latae muscle, it is called the fan type. Studies suggest that damage to the fan type LFCN is unavoidable during conventional fasciotomy.We previously demonstrated that injury to non-fan variation LFCN occurred in 28.6% of patients who underwent THA by fasciotomy performed 2 cm away from the intermuscular space. This suggests that the conventional approach also poses a risk of LFCN injury to non-fan variation LFCN. LFCN injury is rarely reported in the anterolateral approach, which involves incision of fascia further away than the DAA. The purpose of this study is to investigate how the position of fasciotomy in DAA affects the risk of LFCN injury.MethodsWe will conduct a prospective, randomized, controlled study. All patients will be divided into a fan variation and a non-fan variation group using ultrasonography before surgery. Patients with non-fan variation LFCN will receive conventional fasciotomy and lateral fasciotomy in the order specified in the allocation table created in advance by our clinical trial center. The primary endpoint will be the presence of LFCN injury during an outpatient visit using a patient-based questionnaire. The secondary endpoints will be assessed based on patient-reported outcomes at 3 months after surgery in an outpatient setting using the Western Ontario and McMaster Universities Osteoarthritis Index, the Japanese Orthopaedic Association Hip-disease Evaluation Questionnaire, and the Forgotten-Joint Score-12.DiscussionWe hypothesize that the incidence of LFCN injury due to DAA-THA is reduced by making the incision further away from where it is typically made in conventional fasciotomy.If our hypothesis is confirmed, it will reduce the disadvantages of DAA and improve patient satisfaction.Trial registrationUMIN Clinical Trials Registry, UMIN000035945. Registered on 20 February, 2019.

Valuation of angiogenesis in bovine xenografts implanted in intracorporal sites of rabbits as models of in-vivo bioreactors

ABSTRACT The aim of this study was to evaluate neovascularization of bovine xenografts implanted in intracorporeal sites of rabbits (bioreactors). 30 rabbits were used, divided into 6 groups, according to the evaluation time (7, 15, 30, 45, and 60 days); each animal received xenogenic implants in 3 different intracorporeal sites (A1 - omentum bag; A2 - intermuscular space of quadriceps femoris; A3 - subperiosteal of ilium bone). Histological assessments graded the presence of angiogenesis, the number of inflammatory cells, newly formed bone tissue, and the presence of giant cells. Histological analyses showed intense angiogenesis in all implanted xenografts. Presence of inflammatory infiltrate and giant cells at the A1 implant site and presence of bone neoformation at the A3 implant site were noted. Degeneration of implants and formation of a fibrous capsule were noted. When comparing the interaction of the site with the days of evaluation, statistical analysis showed a significant difference (p≤0.05) in any time of neovascularization analysis. The vascular endothelial growth factor (VEGF) and inflammatory cells of the omentum in its structure, may have contributed to the greater presence of neovessels and inflammatory cells, a fact that may indicate functionality as a possible bone substitute.

Variant Anatomy of Popliteal Vessels- A Cadaveric Study

Introduction: The popliteal fossa is a narrow intermuscular space posterior to knee joint. This area is vulnerable during knee arthroplasty or high tibial osteotomy. Therefore, awareness of anatomical variations in the popliteal fossa is important for anatomists, radiologists and surgeons. Popliteal Artery (PA) is frequently affected by penetrating and blunt trauma involving the lower extremity. Therefore, exposure of this artery is often required in both emergency and elective vascular procedures. The Popliteal Vein (PV) is formed at the distal border of popliteus. Pulmonary embolisms originate in deep vein thrombosis in lower extremities. The thrombus forms in the calf veins and subsequently embolize to the lungs. With continued increase of interventional procedures, the anatomical variations in the region of popliteal fossa may have an influence on the success of surgical reconstruction, transluminal angioplasty or embolectomy. Aim: To study the morphology and variations in popliteal vessels by dissection. Materials and Methods: The present study was a cadaveric study which was conducted on 30 lower limbs belonging to 15 formalin fixed adult human cadavers. Properly embalmed adult human cadavers were included in the study. Cadavers with any lower limb deformity or with history of surgery in popliteal fossa were excluded from the study. The data was entered in Microsoft excel sheet and expressed in percentage. Results: According to the classification given by Kim D et al., 96.6% cases were classified as Type IA. Higher bifurcation of PA into posterior tibial and common trunk of anterior tibial and peroneal was described as Type IIB. In addition, the PV was seen to be formed at the lower border of popliteus in 28 specimens (93.33%). Two specimens (6.67%) showed a variable level of formation. Conclusion: Considering such variable morphology of structures in the popliteal fossa, the surgeons operating around the knee joint should be aware of the possible variations in order to avoid undue complications.

Diagnostic value of 68Ga-DOTA-TATE PET/CT imaging for tumor- induced osteomalacia.

Tumor-induced osteomalacia (TIO) is often misdiagnosed as hypophosphatemia that is not valued. The aim of this study was to analyze the diagnostic value of 68Ga-DOTA-TATE PET/CT imaging for TIO. Clinical data was retrospectively collected for 56 patients with suspected TIO at the Affiliated Hospital of Southwest Medical University between January 2016 and December 2019, where patients were examined by 68Ga-DOTA-TATE PET/CT and 99mTc-HYNIC-TOC SPECT. Based on the results of the patient's surgery, the diagnostic efficacy of the two imaging techniques on TIO were analyzed. Of the 56 patients, 41 were diagnosed with TIO, with phosphorus levels ranging from 0.25 to 0.75 mmol/L. The remaining 15 patients were non-TIO. Results of 99mTc-HYNIC-TOC SPECT showed 33 cases were positive, with a diagnostic sensitivity, specificity, and accuracy of 58.54%, 86.67%, and 66.07%, respectively. Results of 68Ga-DOTA-TATE PET/CT imaging showed 46 cases were positive, with a diagnostic sensitivity, specificity, and accuracy of 95.13%, 60.00%, 71.43%, respectively. The average tumor size with 68Ga-DOTA-TATE PET/CT imaging was 2.58±1.71 cm. The lesions of 41 patients involved bone and soft tissue, while 18 patients showed osteolytic bone destruction. Distribution was mainly under the skin, followed by intermuscular space, and cortex of bone. Compared with muscle density, the lesions showed uniformly or slightly lower density nodules. Using 99mTc-HYNIC-TOC SPECT, the planar imaging of 30 patients showed that radioactive uptake increased at the early stage, and it can be accurately positioned on the SPECT imaging. The 68Ga-DOTA-TATE PET/CT imaging demonstrated high accuracy in the diagnosis of TIO and detected small lesions, which could provide more comprehensive information for clinicians, and provide a reference value for the treatment and prognosis of patients.

The signal feature of magnetic resonance imaging of mucosal associated lymphoma tissue lymphoma of the orbit

Objective To investigate the magnetic resonance imaging(MRI) signal characteristics of primary mucosal associated lymphoma tissue lymphoma of the orbit. Methods MRI signal characteristics of 10 cases of orbital mucosal associated lymphoma tissue lymphoma between Sep. 2010 and Aug. 2017 were retrospectively analysed. All cases were confirmed by clinicopathology. MRI plain scan was performed in 10 cases and among them enhanced MRI scan was performed in 8 cases. Results There were 5 cases of single nodule type and 5 cases of diffuse type.Two cases of single nodule type occurred in the eyelid, and 3 cases of single of nodule type occurred in the rear of the eyeball.The diffuse type occurred in the eye muscle, intermuscular space and retrobulbar.MRI signal, T1WI presented equal or slightly high signal, and T2WI presented equal or slightly high signal, and the signal was uniform. The lesion of 8 cases who underwent enhanced scanning presented moderate to severe uniform enhancement. Conclusion The primary orbital mucosal associated lymphoma MRI shows equal or slightly higher signal intensity on T1WI and equal or slightly higher signal intensity on T2WI, which is significantly enhanced by enhanced scanning and shows some characteristics of encircling eyeball growth. Key words: Orbit; Lymphoma, mucosal associated; Magnetic resonance imaging

Dedifferentiated liposarcoma of the musculoskeletal system: expanded MR imaging spectrum from predominant fatty mass to non-fatty mass.

Background The morphology of musculoskeletal dedifferentiated liposarcoma was previously reported as well-defined non-lipomatous masses juxtaposed with fatty tumors. Purpose To establish a new spectrum of magnetic resonance imaging (MRI) findings for dedifferentiated liposarcoma according to the quantity and distribution of the non-fatty component in the tumor. Material and Methods This study consisted of a retrospective review of MRI of 14 patients with a total of 18 histopathologically proven dedifferentiated liposarcoma lesions in the musculoskeletal area. Tumors were classified into four categories (I–IV) according to MR features: I = a well-defined fatty mass and juxtaposed well-defined non-fatty mass; II = a non-fatty component within a predominant fatty mass; III = a focal fatty component within a large non-fatty mass; and IV = a non-fatty mass. Tumor size and depth were also analyzed. Results The MR categorizations of the tumors were as follows: Category I, n = 3; Category II, n = 1; Category III, n = 7; and Category IV, n = 7. The mean tumor size was 11.9 cm (range = 5.0–22.2 cm). Most of the tumors showed a predominant non-fatty area and were deeply located at the intra- or intermuscular space. Conclusion Dedifferentiated liposarcoma lesions showed a diverse spectrum of MRI findings. Although the presence of a non-fatty region within or adjacent to a well-defined fatty mass can suggest dedifferentiated liposarcoma, non-fatty masses without a fatty component were frequent on MRI.

Complications and Prevention Strategies of Oblique Lateral Interbody Fusion Technique.

To analyze the early complications and causes of oblique lateral interbody fusion, and put forward preventive measures. There were 235 patients (79 males and 156 females) analyzed in our study from October 2014 to May 2017. The average age was 61.9 ± 0.21 years (from 32 to 83 years). Ninety-one cases were treated with oblique lateral interbody fusion (OLIF) alone (OLIF alone group) and 144 with OLIF combined with posterior pedicle screw fixation through the intermuscular space approach (OLIF combined group). In addition, 137/144 cases in the combined group were primarily treated by posterior pedicle screw fixation, while the treatments were postponed in 7 cases. There were 190 cases of single fusion segments, 11 of 2 segments, 21 of 3 segments, and 13 of 4 segments. Intraoperative and postoperative complications were observed. Average follow-up time was 15.6 ± 7.5 months (ranged from 6 to 36 months). Five cases were lost to follow-up (2 cases from the OLIF alone group and 3 cases from the OLIF combined group). There were 7 cases of vascular injury, 22 cases of endplate damage, 2 cases of vertebral body fracture, 11 cases of nerve injury, 18 cases of cage sedimentation or cage transverse shifting, 3 cases of iliac crest pain, 1 case of right psoas major hematoma, 2 cases of incomplete ileus, 1 case of acute heart failure, 1 case of cerebral infarction, 3 case of left lower abdominal pain, 9 cases of transient psoas weakness, 3 cases of transient quadriceps weakness, and 8 cases of reoperation. The complication incidence was 32.34%. Thirty-three cases occurred in the OLIF alone group, with a rate of 36.26%, and 43 cases in the group of OLIF combined posterior pedicle screw fixation, with a rate of 29.86%. Fifty-seven cases occurred in single-segment fusion, with a rate of 30.0% (57/190), 4 cases occurred in two-segment fusion, with a rate of 36.36% (4/11), 9 cases occurred in three-segment fusion, with a rate of 42.86% (9/21), and 6 cases occurred in four-segment fusion, with a rate of 46.15% (6/13). In summary, OLIF is a relatively safe and very effective technique for minimally invasive lumbar fusion. Nonetheless, it should be noted that OLIF carries the risk of complications, especially in the early stage of development.

Value and Clinical Application of Orthopedic Metal Artifact Reduction Algorithm in CT Scans after Orthopedic Metal Implantation.

ObjectiveTo evaluate orthopedic metal artifact reduction algorithm (O-MAR) in CT orthopedic metal artifact reduction at different tube voltages, identify an appropriate low tube voltage for clinical practice, and investigate its clinical application.Materials and MethodsThe institutional ethical committee approved all the animal procedures. A stainless-steel plate and four screws were implanted into the femurs of three Japanese white rabbits. Preoperative CT was performed at 120 kVp without O-MAR reconstruction, and postoperative CT was performed at 80–140 kVp with O-MAR. Muscular CT attenuation, artifact index (AI) and signal-to-noise ratio (SNR) were compared between preoperative and postoperative images (unpaired t test), between paired O-MAR and non-O-MAR images (paired Student t test) and among different kVp settings (repeated measures ANOVA). Artifacts' severity, muscular homogeneity, visibility of inter-muscular space and definition of bony structures were subjectively evaluated and compared (Wilcoxon rank-sum test). In the clinical study, 20 patients undertook CT scan at low kVp with O-MAR with informed consent. The diagnostic satisfaction of clinical images was subjectively assessed.ResultsAnimal experiments showed that the use of O-MAR resulted in accurate CT attenuation, lower AI, better SNR, and higher subjective scores (p < 0.010) at all tube voltages. O-MAR images at 100 kVp had almost the same AI and SNR as non-O-MAR images at 140 kVp. All O-MAR images were scored ≥ 3. In addition, 95% of clinical CT images performed at 100 kVp were considered satisfactory.ConclusionO-MAR can effectively reduce orthopedic metal artifacts at different tube voltages, and facilitates low-tube-voltage CT for patients with orthopedic metal implants.

Ultrasound-Guided Costoclavicular Brachial Plexus Block: Sonoanatomy, Technique, and Block Dynamics.

This study aimed to describe in detail the relevant sonoanatomy, technique, and block dynamics of an ultrasound-guided costoclavicular brachial plexus block (BPB). Thirty patients scheduled for hand or forearm surgery under a BPB underwent transverse ultrasound imaging of the medial infraclavicular fossa to identify the cords of the brachial plexus at the costoclavicular space (CCS). An ultrasound-guided BPB was then performed at the CCS with 20 mL of 0.5% ropivacaine. Sensory-motor blockade of the ipsilateral median, radial, ulnar, and musculocutaneous nerves were assessed at regular intervals for 30 minutes after the injection. Successful block was defined as being able to complete surgery under the BPB. The CCS was visualized as a well-defined intermuscular space lying deep and posterior to the mid-point of the clavicle. The cords of the brachial plexus were clustered together lateral to the axillary artery within the CCS. The costoclavicular BPB was successfully performed in all patients, and the median onset time for sensory and motor blockade of all the 4 nerves was 5 [5-15] and 5 [5-10] minutes, respectively. Complete sensory blockade of all the 4 nerves was achieved in 30 [20-30] minutes, and the BPB was successful in 29 (97%) of 30 patients. There were no complications directly related to the technique or the local anesthetic injection. This report describes a novel technique of infraclavicular BPB at the costoclavicular space that produces rapid onset of BPB. Future research should compare the safety and efficacy of this new technique with the traditional lateral sagittal infraclavicular BPB.

Cross-Sectional Nakagami Images in Passive Stretches Reveal Damage of Injured Muscles.

Muscle strain is still awanting a noninvasive quantitatively diagnosis tool. High frequency ultrasound (HFU) improves image resolution for monitoring changes of tissue structures, but the biomechanical factors may influence ultrasonography during injury detection. We aim to illustrate the ultrasonic parameters to present the histological damage of overstretched muscle with the consideration of biomechanical factors. Gastrocnemius muscles from mice were assembled and ex vivo passive stretching was performed before or after injury. After injury, the muscle significantly decreased mechanical strength. Ultrasonic images were obtained by HFU at different deformations to scan in cross and longitudinal orientations of muscle. The ultrasonography was quantified by echogenicity and Nakagami parameters (NP) for structural evaluation and correlated with histological results. The injured muscle at its original length exhibited decreased echogenicity and NP from HFU images. Cross-sectional ultrasonography revealed a loss of correlation between NP and passive muscle stretching that suggested a special scatterer pattern in the cross section of injured muscle. The independence of NP during passive stretching of injured muscle was confirmed by histological findings in ruptured collagen fibers, decreased muscle density, and increased intermuscular fiber space. Thus, HFU analysis of NP in cross section represents muscle injury that may benefit the clinical diagnosis.