Anterior Pelvic Research Articles

Study on the Consistency Between Automatic Measurement Based on Convolutional Neural Network Technology and Manual Visual Evaluation in Intracavitary Ultrasonic Cine of Anterior Pelvic.

This study was to evaluate the application of automatic measurement based on convolutional neural network (CNN) technology in intracavitary ultrasound cine of anterior pelvic. A total of 500 patients who underwent pelvic floor ultrasound examination at Peking University Shenzhen Hospital from July 2021 to February 2022 were retrospectively retrieved by the picture archiving and communication system (PACS) system, and 300 cases were used as a training set. The training set was labeled by three experienced ultrasound physicians to train CNN models and develop an automatic measurement software. The remaining 200 cases were used as a test set. Automatic measurement software identified relevant anatomical structures frame by frame and determined the two frames with the greatest difference, calculated the bladder neck descent (BND), urethral rotation angle (URA), and retrovesical angle (RA). Meanwhile, two experienced ultrasound physicians evaluated the resting frame and the maximum Valsalva frame on the cines by manual visual evaluation, labeled the anatomical structures in the corresponding frame, such as the inferoposterior margin of pubic symphysis, the mid-axis of pubic symphysis, bladder contour, and urethra in the front, and calculated BND, URA, and RA. Considering that the residual urine volume (RUV) in the bladder may affect the results, enrolled patients were grouped according to the RUV (10-50 mL, 50-100 mL, and >100 mL). The consistency of the results by automatic measurement and manual visual evaluation was evaluated using the intraclass correlation coefficient (ICC) and the Bland-Altman graph. Of the 200 cases in the test set, 120 cases were successfully identified by the CNN automatic software with a 60% recognition rate. In the case of successful identification, the ICC of manual visual evaluation measurement and automatic measurement was 0.936 (BND), 0.911 (URA), 0.756 (RA in rest), and 0.877 (RA at maximum Valsalva), respectively. In addition, the RUV had a negligible effect on the consistency. The Bland-Altman plot shows the proportion of samples outside the limit was below 5%. CNN-based automatic measurement software exhibited high reliability in anterior pelvic measurement, which results in a significantly enhanced measurement efficiency.

A nerve-to-implant distance as a novel predictor for lateral femoral cutaneous nerve injuries after anterior subcutaneous pelvic internal fixation.

Although anterior subcutaneous pelvic internal fixation is a valuable tool for the reduction and fixation of unstable pelvic ring injuries, lateral femoral cutaneous nerve irritation by the implant is the most common complication. This study aimed to investigate the association between the nerve-to-implant distance and the postoperative lateral femoral cutaneous nerve symptom. Patients who underwent anterior subcutaneous pelvic internal fixation between 2016 and 2019 were retrospectively analyzed. Lateral femoral cutaneous nerve status was defined as follows: not identified, nerve-to-implant distance <13 mm, and ≥13 mm. The proportion of patients who experienced postoperative nerve disorders was compared using the nerve status. Nerve-to-implant distances were compared using the presence or absence of postoperative lateral femoral cutaneous nerve disorders. The predictive value of a nerve-to-implant distance of 13 mm for postoperative nerve disorders was assessed. Overall, 26 lateral femoral cutaneous nerves were included. Ten patients had postoperative nerve disorders, of which seven had an nerve-to-implant distance <13 mm, while the other three occurred in patients whose nerves were not identified. A nerve-to-implant distance ≥13 mm was significantly associated with a decreased risk of postoperative nerve disorder compared to a nerve-to-implant distance <13 mm (p = 0.017). A nerve-to-implant distance ≥13 mm had a perfect sensitivity (100%) and modest specificity (58.3%). Nerve-to-implant distance was ≥13 mm. Nerve disorders were frequently observed when the nerve-to-implant distance was <13 mm or the nerve was not identified intraoperatively. Efforts to identify the lateral femoral cutaneous nerve may be useful to avoid internal fixation-related nerve disorders.

PUBIC SYMPHYSIS DIASTASIS TREATED WITH ANTERIOR SUBCUTANEOUS INTERNAL PELVIC FIXATOR A CASE REPORT

This is a new method of treatment for Pubic Symphysis diastasis with anterior subcutaneous pelvic internal fixation (later called as INFIX) using pedicle screws and a spinal rod. Pedicle screw and Spinal rod was used to address shortcomings of external fixation (EXFIX).Pedicle screws were passed into AIIS through small incision. Contoured Spinal rod of suitable length passed across the lower abdominal wall in subcutaneous plane, compression achieved manually and rod connected to screws and tightened. Patient is able to tolerate implants and is able to sit, stand and walk without difficulty. Complications include lateral femoral cutaneous nerve irritation, which resolved after 5weeks. Appearance of INFIX provides a new alternative treatment; INFIX is minimally invasive and time-saving for treatment of anterior pelvic ring injuries. The EXFIX is an effective tool for anterior ring fixation and has been widely used. However, it is associated with many complications such as pin-track infection, aseptic loosening and loss of reduction. INFIX is less disabling for treatment of Pubic Symphysis Diastasis.

Mesane Ekstrofisi Tedavisinde Ortopedik Cerrahi Yaklaşımlar

Bladder exstrophy is an embryologic malformation that affects urogenital and skeletal systems. Non-operative treatment of this rare problem is impossible. Urogenital reconstructions can be facilitated by orthopedic procedures. These reconstructions can be performed in a single stage as a complete repair or multi-stage approaches. The goal of the treatment is closure of the bladder and abdominal wall for the achievement of continence, preservation of renal functions, and cosmetic and functional reconstruction of genital organs. Orthopedic procedures are performed to decrease the tension that complicates the bladder and abdominal wall closure by approximating the pubic rami to achieve a secure closure and a low recurrence rate. Surgical interventions consist of the approximation of the pubic rami with different materials such as suture materials and plaque or the application of different osteotomy types such as posterior iliac, anterior pelvic (pubic), diagonal iliac, horizontal iliac and posterior pelvic resection osteotomies. The age of the patient, the amount of pubic diastasis and history of previous operations that the patient has undergone should be considered during the operation planning. Pubic rami can be approximated without performing pelvic osteotomy in patients who are operated within the first 72 hours after birth. But, osteotomy is required in children older than 2 years of age with severe pubic diastasis, concomitant cloacal exstrophy and unsuccessful operation history. The surgical team should have enough knowledge and experience to perform different osteotomy types in case of need to combine anterior and posterior iliac osteotomies. With these multidisciplinary approaches, much more successful outcomes could be achieved.

Comparison of effectiveness of anterior subcutaneous internal fixator and plate internal fixation for unstable anterior pelvic ring fractures

To compare the effectiveness of anterior subcutaneous pelvic internal fixator (INFIX) and plate internal fixation in treatment of unstable anterior pelvic ring fractures. The clinical data of 48 patients with unstable anterior pelvic ring fractures who met the selection criteria between June 2014 and December 2019 were retrospectively analyzed. Among them, 21 cases were treated with INFIX (INFIX group), and 27 cases were treated with plate (plate group). There was no significant difference in gender, age, body mass index, cause of injury, time from injury to operation, Injury Severity Score (ISS), and fracture type between the two groups ( P>0.05). The operation time, intraoperative blood loss, fracture healing time, partial weight-bearing time, and complete weight-bearing time were recorded and compared between the two groups. Matta standard was used to evaluate the quality of fracture reduction, and Majeed score system was used to evaluate the functional recovery of pelvic fracture after operation. The patients in both groups were followed up for an average of 12.5 months (range, 6-16 months). The operation time and intraoperative blood loss in INFIX group were significantly lower than those in plate group ( t=-11.965, P=0.000; t=-20.105, P=0.000). There was no significant difference in the quality of fracture reduction, fracture healing time, partial weight-bearing time, and complete weight-bearing time between the two groups ( P>0.05). At 14 weeks after operation, there was no significant difference in the scores of pain, working, standing and walking, and total scores between INFIX group and plate group ( P>0.05), but there were significant differences in sitting and sexual intercourse scores ( t=-4.250, P=0.003; t=-6.135, P=0.006). The incidences of lateral femoral cutaneous nerve injury, femoral nerve injury, and heterotopic ossification were significantly higher in INFIX group than in plate group ( P<0.05), while the incidence of incision infection was lower in INFIX group than in plate group ( P<0.05). Compared with the plate internal fixation, the INFIX internal fixation can obtain the similar effectiveness for the unstable anterior pelvic ring fracture and has the advantages of shorter operation time, less blood loss, and lower risk of infection.

Combined Anterior Pelvic (CAP) approach for fracture acetabulum fixation - Functional outcome evaluation and predictors of outcome

ObjectiveIlio-inguinal approach has been considered standard anterior approach for acetabulum fracture fixation. Different modifications of this approach have been described. This study analysed the patients treated using a Combined Anterior Pelvic (CAP) approach - minimal AIP (anterior intra-pelvic) with modified ilio-femoral along with ’anterior superior iliac spine’ osteotomy. This combined approach provides wide exposure of pelvis to direct visualise the entire anterior column from sacroiliac joint to pubic symphysis, medial side of quadrilateral plate and entire iliac wing with minimal retraction of soft tissues required. MethodsData of patients treated from July 2014 to June 2018 for acetabulum fracture using CAP approach was retrieved from hospital record system. Inclusion criteria were - acetabulum fractures treated surgically using CAP approach. Exclusion criteria were – age less than 18 years, associated pelvis ring injury and incomplete peri-operative radiological record (pre-operative/post-operative antero-posterior, 45° obturator and 45° iliac oblique radiographs and pre-operative computed tomographic (CT) scans. 62 patients who met inclusion exclusion criteria were called in out-patient-department for final functional evaluation using Matta modified Merle d’aubigne score. ResultsOut of 62 patients 47 patients who turned up for final functional evaluation were included in study. 19 patients had excellent, 15 had good, 2 had fair and 11 had poor results. Age less than 40 years, anterior column fracture pattern, Pre-operative fracture displacement >20 mm, fracture comminution and post-operative fracture reduction within 3 mm were the predictors of the functional outcome. When analysed using logistic regression model, post-operative fracture reduction was found to be the only significant predictor of functional outcome. ConclusionCAP approach is useful anterior approach to acetabulum. Fracture reduction is the independent predictor of functional outcome. Comparison of this approach with other anterior approaches to acetabulum can be area of further research.

MP05-01 IS THE H LINE BETTER THAN CURRENT REFERENCE LINES FOR CLASSIFYING ANTERIOR PELVIC PROLAPSE ON MAGNETIC RESONANCE IMAGING?

You have accessJournal of UrologyUrodynamics/Lower Urinary Tract Dysfunction/Female Pelvic Medicine: Pelvic Prolapse (MP05)1 Apr 2020MP05-01 IS THE H LINE BETTER THAN CURRENT REFERENCE LINES FOR CLASSIFYING ANTERIOR PELVIC PROLAPSE ON MAGNETIC RESONANCE IMAGING? Kevin Rechi Sierra*, Joan Garcia Ibañez, Francisco Sánchez Ballester, Alba Monzó Cataluña, Sara Mitjana Biosca, Marta Diranzo Garcia, Miguel Beltrán Puig, Joaquín Ulises Juan Escudero, Iván José Povo Martín, Paola Pardo Duarte, and Emilio López Alcina Kevin Rechi Sierra*Kevin Rechi Sierra* More articles by this author , Joan Garcia IbañezJoan Garcia Ibañez More articles by this author , Francisco Sánchez BallesterFrancisco Sánchez Ballester More articles by this author , Alba Monzó CataluñaAlba Monzó Cataluña More articles by this author , Sara Mitjana BioscaSara Mitjana Biosca More articles by this author , Marta Diranzo GarciaMarta Diranzo Garcia More articles by this author , Miguel Beltrán PuigMiguel Beltrán Puig More articles by this author , Joaquín Ulises Juan EscuderoJoaquín Ulises Juan Escudero More articles by this author , Iván José Povo MartínIván José Povo Martín More articles by this author , Paola Pardo DuartePaola Pardo Duarte More articles by this author , and Emilio López AlcinaEmilio López Alcina More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000000819.01AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: Magnetic resonance imaging is useful to study pelvic organ prolapses (POP). At present, two reference lines are used indistinctly: the pubococcygeal line (PCL) and the midpubic line (MPL). The H line is used for measuring pelvic floor relaxation, but not for staging POP. The aim of the study is to compare clinical staging of anterior pelvic prolapse with MRI staging, using the PCL, MPL and the H line as reference lines. Moreover, we want to analyze inter-rater reliability of each reference line. METHODS: We studied 42 women with POP symptoms using both physical examination and an MRI. We performed physical exam using the pelvic organ prolapse quantification (POP-Q) system. Two different observers calculated anterior POP using the three MRI reference lines. Agreement between MRI and clinical staging was estimated using Pearson Correlation for the quantitative measurements and weighted kappa for the stages. Inter-rater reliability was estimated using intraclass correlation coefficient (ICC). RESULTS: Agreement between physical exam and the H line was high by both observers (r= 0,86 and r= 0,76). However, agreement was lower using MPL (r= 0,76 and r= 0,65). The results of comparing MRI staging and physical examination were: κ = 0,618 and κ =0,602 for the H line, κ =0,273 and κ = 0,267 for MPL and κ = -0,105 and κ = -0,140 for PCL. The results of inter-rate reliability were: ICC of 0,968 for the H line, ICC of 0,788 for MPL and ICC of 0,737 for PCL. CONCLUSIONS: In our experience, anterior POP staging using MRI H line as a reference presents a better agreement with clinical staging than PCL or MPL. Furthermore, the H line has a better inter-rate reliability. Thus, the H line could be used as a reference line to measure anterior POP on MRI instead of the current lines. Source of Funding: No source of funding © 2020 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 203Issue Supplement 4April 2020Page: e41-e41 Advertisement Copyright & Permissions© 2020 by American Urological Association Education and Research, Inc.MetricsAuthor Information Kevin Rechi Sierra* More articles by this author Joan Garcia Ibañez More articles by this author Francisco Sánchez Ballester More articles by this author Alba Monzó Cataluña More articles by this author Sara Mitjana Biosca More articles by this author Marta Diranzo Garcia More articles by this author Miguel Beltrán Puig More articles by this author Joaquín Ulises Juan Escudero More articles by this author Iván José Povo Martín More articles by this author Paola Pardo Duarte More articles by this author Emilio López Alcina More articles by this author Expand All Advertisement PDF downloadLoading ...

Pedicle screw internal fixation versus subcutaneous anterior pelvic internal fixation in treatment of pelvic anterior ring fractures

Objective To compare pedicle screw internal fixation (PSIF) and subcutaneous anterior pelvic internal fixation (APIF) in the treatment of pelvic anterior ring fractures. Methods A retrospective study was conducted of a consecutive series of 46 patients who had undergone surgery for anterior ring pelvic fractures at Department of Orthopaedic Surgery, The People’s Hospital of Henan Province from January 2014 to September 2018. Of them, 20 were treated by PSIF and 26 by APIF. In the PSIF group, there were 12 males and 8 females with an age of 47.8±2.4 years, and 6 cases of B1, 9 cases of type B2, 4 cases of type B3 and one case of type C1 by the Tile’s classification; in the APIF group, there were 16 males and 10 females with an age of 49.6±1.2 years, and 9 cases of B1, 8 cases of type B2, 5 cases of type B3, 2 cases of type C1 and 2 cases of type C2 by the Tile’s classification. The 2 groups were compared in terms of surgical or postoperative complications (including iatrogenic nerve injury, infection, implant failure and fracture nonunion), fracture reduction and therapeutic efficacy at the final follow-up. Results There were no significant differences between the 2 groups of patients in their preoperative general data, indicating they were compatible(P>0.05). The 46 patients were followed up for 9 to 18 months (mean, 13.5 months). In the PSIF and APIF groups, the incidences of injury to the lateral femoral cutaneous nerve were 5.0%(1/20) and 7.7%(2/26), those of infection 5.0%(1/20) and 3.8%(1/26), and those of skin discomfort 5.0% (1/20) and 7.7%(2/26), respectively. According to the Matta criteria, the fracture reduction at the last follow-up was evaluated as excellent in 7, as good in 11 and as fair in 2 in the PSIF group, giving an excellent and good rate of 90.0%, and as excellent in 9, as good in 13 and as fair in 4 in the APIF group, giving an excellent and good rate of 84.6%. According to the Majeed criteria, the pelvic function at the final follow-up was evaluated as excellent in 10, as good in 7, as fair in 2 and as poor in one in the PSIF group, giving an excellent and good rate of 85.0%, and as excellent in 13, as good in 10, and as fair in 3 in the APIF group, giving an excellent and good rate of 88.5%. There were no significant differences between the 2 groups in all the comparisons above (P>0.05). The incidence of femoral nerve parasthesia was 0(0/20) for the PSIF group, significantly lower than that for the APIF groups (3.8%, 1/26) (P<0.05). Conclusion As both PSIF and APIF lead to similar clinical efficacy in the treatment of pelvic anterior ring fracture, either of them can be selected as an appropriate surgical procedure depending on the patient’s situation and surgeon’s experience. Key words: Pelvis; Fractures, bone; Fracture fixation, internal; Bone plates; Surgical procedures, minimally invasive

Minimally invasive anterior pelvic internal fixation: An anatomic study comparing Pelvic Bridge to INFIX

ObjectivesAnterior external fixation for pelvic ring fractures has shown to effectively improve stability and reduce mortality. However, these fixators can be associated with substantial morbidity such as pin tract infection, premature loss of fixation, and decreased quality of life in patients. Recently, two new methods of subcutaneous anterior pelvic internal fixation have been developed; the INFIX and the Pelvic Bridge. These methods have the purported advantages of lower wound complications, less surgical site pain, and improved quality of life.We sought to investigate the measured distances to critical anatomic structures, as well as the qualitative and topographic differences notable during implantation of both devices in the same cadaveric specimen. Materials and methodsThe Pelvic Bridge and INFIX were implanted in eleven fresh cadavers. Distances were then measured to: the superficial inguinal ring, round ligament, spermatic cord, lateral femoral cutaneous nerve (LFCN), femoral nerve, femoral artery, and femoral vein. Observations regarding implantation and topography were also recorded. ResultsThe INFIX had greater measured distances from all structures except for the LFCN, in which its proximity placed this structure at risk. Neither device appears to put other critical structures at risk in the supine position. Significant implantation and topographic differences exist between the devices. The INFIX application lacked “safety margins” concerning the LFCN in 10/11 (90.9%) specimens, while Pelvic Bridge placement lacked “safety margins” with regard to the right superficial ring (1/11, 9%) and the right spermatic cord (1/11, 9%). ConclusionsBoth the Pelvic Bridge and INFIX lie at safe distances from most critical pelvic structures in the supine position, though INFIX application places the LFCN at risk.

The use of an anterior pelvic internal fixator to treat disruptions of the anterior pelvic ring: a report of technique, indications and complications.

The anterior pelvic internal fixator is increasingly used for the treatment of unstable, or displaced, injuries of the anterior pelvic ring. The evidence for its use, however, is limited. The aim of this paper is to describe the indications for its use, how it is applied and its complications. We reviewed the case notes and radiographs of 50 patients treated with an anterior pelvic internal fixator between April 2010 and December 2015 at a major trauma centre in the United Kingdom. The median follow-up time was 38 months (interquartile range 24 to 51). Three patients were excluded from the analysis leaving 47 patients with complete follow-up data. Of the 47 patients, 46 achieved radiological union and one progressed to an asymptomatic nonunion. Of the remaining patients, 45 required supplementary posterior fixation with percutaneous iliosacral screws, 2 of which required sacral plating. The incidence of injury to the lateral femoral cutaneous nerve (LFCN) was 34%. The rate of infection was 2%. There were no other significant complications. Without this treatment, 44 patients (94%) would have needed unilateral or bilateral open reduction and plate fixation extending laterally to the hip joint. The anterior pelvic internal fixator reduces the need for extensive open surgery and is a useful addition to the armamentarium for the treatment of anterior pelvic injuries. It is associated with injury to the LFCN in a third of patients. Cite this article: Bone Joint J 2017;99-B.1232-6.

The Pelvic Bridge: A Subcutaneous Approach for Anterior Pelvic Fixation.

An alternative method to external fixation for the treatment of unstable anterior pelvic ring injuries, termed the pelvic bridge technique, provides equivalent results with fewer complications and is performed using occipital cervical rods subcutaneously, with fixation into the iliac wings and parasymphyseal bone. For preoperative planning, review the appropriate imaging, including radiographs and computed tomography (CT) scans, to mesh the findings on imaging to the clinical picture of the patient and ensure that the patient meets operative criteria and that none of the contraindications are present. Position the patient to facilitate anterior and posterior fixation. Make the incisions necessary to expose the osseous contour where fixation will be utilized. Carefully contour the plate-rod construct, which is necessary to minimize postoperative complications. Use care when inserting the rod as doing so will help to avoid neurovascular complications. To recreate pelvic stability, the pelvic ring needs to heal in as close to anatomic position as possible and there are multiple methods that help to obtain an adequate reduction. Multiple constructs may be used to stabilize the anterior pelvic ring, but the fundamental principle is to attach the 2 hemipelves to achieve stability, and the location where fixation can be achieved depends on the fracture pattern. Ensure meticulous closure to reduce the chance of infection and achieve appropriate soft-tissue coverage over hardware. Early mobilization is a fundamental goal of this procedure, but the time to full weight-bearing is dependent on fracture characteristics and healing. Anterior pelvic internal fixation (APIF) using the pelvic bridge technique has been demonstrated to have significantly fewer complications than APEF2.

Midterm radiologic and functional outcomes of minimally-invasive fixation of unstable pelvic fractures using anterior internal fixator(INFIX) and percutaneous iliosacral screws.

Anterior pelvic external fixation is associated with pin site infections, aseptic loosening with loss of reduction, frame bulkiness hindering patient mobilization and consequent difficulties in inpatient nursing. We performed a single-center prospective series to evaluate the feasibility, safety, limitations and midterm radiologic and functional outcomes of an alternative minimally invasive pelvic internal fixation technique using an anterior subcutaneous pelvic internal fixator (INFIX) and percutaneous iliosacral screws in unstable pelvic ring fractures. Fifteen consecutive patients with vertically and/or rotationally unstable pelvic fractures, presenting to a Level-1 trauma center were treated with closed reduction, appropriate posterior stabilization with percutaneous iliosacral screws and anterior INFIX application. Outcomes were analyzed with respect to the quality of fracture reduction (Matta's radiologic criteria), ease of inpatient nursing, patient mobility and comfort, functional outcomes at final follow-up (Majeed score, SF-12 score), social reintegration and complications. Most common injury pattern was AO/OTA type 61-C pelvic fracture in thirteen patients. Mean procedure time and intra-operative blood loss were, 57.1+/-4.9min (range,51-68min) and 115.3+/-26.7ml (range,80-170ml) respectively. Mean follow-up was 34.9+/-4.1 months (range,31-42 months). Fracture reduction was excellent in twelve and good in three patients (Matta's criteria). Functional outcomes were excellent in eight and good in seven patients (Majeed score). Mean SF-12 scores for physical and mental health were 48.58+/-5.61 and 50.89+/-3.97 respectively. Thirteen patients returned to their pre-injury jobs. All fifteen patients reintegrated into society without any restrictions. INFIX was removed at a mean post-operative period of 7.3+/-1.5 months (range,5.5-11 months). Complications included, lateral femoral cutaneous nerve irritation(n=1), superficial wound infection(n=1) and loss of reduction(n=2). Minimally invasive pelvic stabilization using INFIX and percutaneous iliosacral screws is easy to learn and apply, achieves good fracture reduction and definitive stabilization with minimum complications and offers excellent functional outcomes at a minimum follow-up of 31 months. Level IV.

Tissue memory B cell repertoire analysis after ALVAC/AIDSVAX B/E gp120 immunization of rhesus macaques.

The ALVAC prime/ALVAC + AIDSVAX B/E boost RV144 vaccine trial induced an estimated 31% efficacy in a low-risk cohort where HIV‑1 exposures were likely at mucosal surfaces. An immune correlates study demonstrated that antibodies targeting the V2 region and in a secondary analysis antibody-dependent cellular cytotoxicity (ADCC), in the presence of low envelope-specific (Env-specific) IgA, correlated with decreased risk of infection. Thus, understanding the B cell repertoires induced by this vaccine in systemic and mucosal compartments are key to understanding the potential protective mechanisms of this vaccine regimen. We immunized rhesus macaques with the ALVAC/AIDSVAX B/E gp120 vaccine regimen given in RV144, and then gave a boost 6 months later, after which the animals were necropsied. We isolated systemic and intestinal vaccine Env-specific memory B cells. Whereas Env-specific B cell clonal lineages were shared between spleen, draining inguinal, anterior pelvic, posterior pelvic, and periaortic lymph nodes, members of Env‑specific B cell clonal lineages were absent in the terminal ileum. Env‑specific antibodies were detectable in rectal fluids, suggesting that IgG antibodies present at mucosal sites were likely systemically produced and transported to intestinal mucosal sites.

“Anterior subcutaneous pelvic internal fixator (INFIX), Is it safe?” A cadaveric study

IntroductionAnterior pelvic internal fixator (INFIX) is used to treat unstable pelvic ring injuries. Nerve injury complications with this procedure have been reported. ObjectivesThis anatomic study attempted to identify structures at risk after application of INFIX. Materials and methodsINFIX was applied in fifteen fresh, frozen, anatomical specimens using polyaxial pedicular screws and subcutaneous rods. Surgical dissection was done to identify the structures at risk including the femoral nerve (FN), femoral artery (FA), femoral vein (FV) and the lateral femoral cutaneous nerve (LFCN) related to which are potentially affected by the implant. ResultsAll structures at risk were closer to the rod than to the pedicular screw. Measurements were made between the rod and the structures at risk. The LFCN was an average of 13.49±1.65mm (95% CI 12.871–14.103) from the lateral end of the rod. The FN was an average of 12.43±3.42mm (95% CI 11.151–13.709), the FA was an average of 12.80±3.67 (95% CI 11.430–14.173) and the FV was an average of 13.48±3.73 (95% CI 12.082–14.871) below the rod. No direct compression of the rod to the structure at risk was observed. ConclusionsThe femoral nerve is the structure most at risk of compression by the INFIX rod. Careful surgical technique is required in every step of this surgery. We suggest using polyaxial screws and recommend that during screw insertion the surgeon should leave some space between the screw and rectus fascia. The the rod should be trimmed as short as possible to reduce LFCN irritation.

Virtual mapping of 260 three-dimensional hemipelvises to analyse gender-specific differences in minimally invasive retrograde lag screw placement in the posterior acetabular column using the anterior pelvic and midsagittal plane as reference

BackgroundDue to complex pelvic geometry, percutaneous screw placement in the posterior acetabular column can pose a major challenge even for experienced surgeons.MethodsThe present study examined the preformed bone stock of the posterior acetabular column in 260 hemipelvises. Retrograde posterior column screws were virtually implanted using iPlan® CMF (BrainLAB AG, Feldkirchen, Germany); maximal implant length, maximal implant diameter and angles between the screw trajectories and the reference planes anterior pelvic plane as well as the midsagittal plane were assessed for gender-specific differences.ResultsThe virtual analysis of the preformed bone stock column showed two constrictions of crucial clinical importance. These were located 49.6 ± 3.4 (41.0–60.2) mm (inferior margin of acetabulum) and 77.0 ± 5.6 (66.5–95.3) mm (centre of acetabulum) from the entry point of the implant in men and respectively 43.7 ± 2.3 (38.3–49.3) mm as well as 71.2 ± 3.5 (63.5–79.99) mm in women (men vs. women: p < 0.001). The entry point of the retrograde posterior column screw was located dorsal from the transition of the lower margin of the ischial tuberosity to ramus inferior pointing to the medial margin of the ischial tuberosity. In female patients, the entry point was located significantly closer to the medial margin of the ischial tuberosity. However, 7.3 mm screws can generally be used in men and women. The angle between the screw trajectory and the anterior pelvic plane in sagittal section was 14.0 ± 4.9 (2.5–28.6) °, the angle between the screw trajectory and the midsagittal plane in axial section was 31.1 ± 12.8 (1.5–77.9) ° and the angle between the screw trajectory and the midsagittal plane in coronal section was 8.4 ± 3.8 (1.5–20.0) °. For all angles, significant gender-specific differences were found (p < 0.001).ConclusionTherefore, the anterior pelvic plane as well as the midsagittal plane can facilitate intraoperative orientation for retrograde posterior column screw placement considering gender-specific differences in preformed bone corridor, implant length as well as angles formed between screw trajectory and these reference planes.

Retrograde lag screw placement in anterior acetabular column with regard to the anterior pelvic plane and midsagittal plane—Virtual mapping of 260 three-dimensional hemipelvises for quantitative anatomic analysis

Percutaneous screw placement can be used for minimally invasive treatment of none or minimally displaced fractures of the anterior column. The complex pelvic geometry can pose a major challenge even for experienced surgeons. The present study examined the preformed bone stock of the anterior column in 260 hemipelvises (130 male and 130 female). Screws were virtually implanted using iPlan® CMF (BrainLAB AG, Feldkirchen, Germany); the maximal implant length and the maximal implant diameter were assessed.The study showed, that 6.5mm can generally be used in men; in women however individual planning is essential in regard to the maximal implant diameter since we found that in 15.4% of women, screws with a diameter less than 6.5mm were necessary.The virtual analysis of the preformed bone stock corridor of the anterior column showed two constrictions of crucial clinical importance. These can be found after 18% and 55% (men) respectively 16% and 55% (women) measured from the entry point along the axis of the implant.The entry point of the retrograde anterior column screw in our collective was located lateral of tuberculum pubicum at the level of the superior-medial margin of foramen obturatum. In female patients, the entry point was located significantly more lateral of symphysis and closer to the cranial margin of ramus superior ossis pubis.The mean angle between the screw trajectory and the anterior pelvic plane in sagittal section was 31.6±5.5°, the mean angle between the screw trajectory and the midsagittal plane in axial section was 55.9±4.6° and the mean angle between the screw trajectory and the midsagittal plane in coronal section was 42.1±3.9° with no significant deviation between both sexes. The individual angles formed by the screw trajectory and the anterior pelvic and midsagittal plane are independent from anthropometric parameters sex, age, body length and weight. Therefore, they can be used for orientation in lag screw placement keeping in mind that the entry point differs in both sexes.

Failure and Salvage of “INFIX” Instrumentation for Pelvic Ring Disruption in a Morbidly Obese Patient

Open-book pelvic fractures in the obese patient are accompanied by an increased risk of fixation failure. We report on the use of a recently described anterior subcutaneous pelvic internal fixator, the "INFIX" technique, in a morbidly obese patient. In this case, single and double rod constructs alone did not maintain adequate fixation due to the extreme forces in a morbidly obese patient. Successful salvage of the construct and satisfactory healing was achieved with the addition of 2 cross-links between the double rods of the INFIX.

Anterior Pelvic Reduction and Fixation Using a Subcutaneous Internal Fixator

Acute traumatic pelvic instability mandates reduction and mechanical stabilization to maximize the chance of a good functional outcome. Posterior pelvic fixation is frequently inadequate to stabilize the pelvic ring in isolation. Fixation augmentation with anterior pelvic ring implants can take several forms, including plates, medullary screws, or external fixation. Based on a multitude of patient and injury factors, external fixation may be the definitive anterior pelvic implant of choice. However, many drawbacks exist with this treatment, most notably the high infection rates of the transcutaneous pins, impaired patient mobilization, and suboptimal mechanical properties. We present a technique of a subcutaneous anterior pelvic fixator as an alternative method of anterior pelvic ring reduction and stabilization that avoids many of the drawbacks of traditional anterior pelvic external fixation.

Anterior Pelvic External Fixator Versus Subcutaneous Internal Fixator in the Treatment of Anterior Ring Pelvic Fractures

To compare the short-term results of anterior pelvic external fixation (APEF) versus anterior pelvic internal fixation (APIF) applied subcutaneously in the context of surgical treatment of pelvic ring injuries. A single center retrospective chart review. A level 1 trauma center. A consecutive series of 48 patients who underwent surgical stabilization of their anterior pelvic ring (24 utilizing APIF and 24 utilizing APEF) by 2 surgeons at a single hospital were studied. The choice to use either APEF or APIF was left up to each surgeon, the indications for use are the same. Data collected included surgical or postoperative complications including infection, implant failure, reoperation, documented surgical site pain persisting to clinical follow-up visits, and radiographic union. Measurements on inlet and outlet pelvic radiographs were made immediately postoperation and at all follow-up clinic visits to determine whether there were differences in maintaining pelvic fracture reduction. Statistical analysis was performed to evaluate significant differences between the 2 groups with regard to each of these variables. The APIF group was found to have a significantly lower incidence of wound complication (P < 0.05) and a lower occurrence of associated morbidity events as compared with the APEF group. In addition, the APIF group was found to have a significantly lower rate of surgical site pain persisting through all clinical follow-up intervals (P = 0.05). There was no difference between the 2 groups in terms of maintenance of pelvic reduction in the early postoperative phase or at final follow-up. No other significant differences were observed between the 2 groups. The present study, which was based on our initial experience with the subcutaneous anterior pelvic fixator, demonstrated encouraging clinical outcomes in terms of a lower wound complication rate and associated morbidity, and surgical site symptoms, although maintaining equivalent reduction. These findings suggest that further analysis of this technique is warranted to determine if it can be definitively recommended for general use. Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Anterior Pelvic Subcutaneous Internal Fixator Application

To determine what anatomic structures are at risk after the application of a subcutaneous anterior pelvic internal fixator (APIF), from an incision over the anterior iliac crest to an incision centered over the pubic symphysis (Pfannenstiel). A laboratory investigation was performed using 5 fresh, frozen, nonpreserved cadaveric specimens (3 male specimens, 2 female specimens). Dissections were carried out to identify the relationships and proximity between the fixator screw constructs and various anatomic structures, including the (1) lateral femoral cutaneous nerve (LFCN), (2) ilioinguinal nerve (IIN), (3) iliohypogastric nerve (IHN), (4) femoral nerve, (5) femoral artery, (6) femoral vein, (7) genitofemoral nerve; and (8) spermatic cord or round ligament. The mean and range of distance from each of these structures to the implant were measured with calipers. Despite variations in pelvic anatomy and width of pelvic brims, precontoured fixators (3.5 locking reconstruction plates) did not violate any pelvic neurovascular structures using this recommended application of an APIF. The spermatic cord was easily avoided as they were directly visualized using our application technique (mean, 0.4 cm, range, 0-2 cm). Abdominal musculature protected the IHN and IIN for most of their course, with the precontoured plates remaining inferior to their course and resting superficial to their branches (IHN mean, 1.5 cm, range, 1.2-1.8 cm and IIN mean, 2.1 cm, range, 0.9-4 cm). The LFCN traveled safely posterior to the inguinal ligament, thus being bridged by the internal spanning fixation without visualized disruption, impingement, or violation (mean, 1.5 cm, range, 0.6-4 cm). Finally, the femoral nerve, artery, and vein collectively demonstrated safe distance from the risk of compression (mean, 2.2 cm, range, 0.8-3.7 cm). The anatomic structures hypothesized to be potentially endangered because of the lack of direct visualization during APIF placement, include the LFCN, IIN, IHN, femoral nerve, femoral artery, and femoral vein. Based upon our anatomic study, APIF, which may be used for treatment augmentation of anterior pelvic ring disruptions, does not place these structures at significant risk. In addition, the reproductive structures (round ligament and spermatic cord) are in direct visualization and can easily be avoided during implant placement.