The effect of increased hip flexion using stirrups on lower-extremity venous flow: a prospective observational study

Position- and posture-dependent vascular imaging-a scoping review

OBJECTIVES

Position- and posture-dependent deformation of the vascular system is a relatively unexplored field. The goal of this scoping review was to create an overview of existing vascular imaging modalities in different body positions and postures and address the subsequent changes in vascular anatomy.

METHODS

Scopus, Medline, and Cochrane were searched for literature published between January 1, 2000, and June 30, 2022, incorporating the following categories: image modality, anatomy, orientation, and outcomes.

RESULTS

Out of 2446 screened articles, we included 108. The majority of papers used ultrasound (US, n = 74) in different body positions and postures with diameter and cross-sectional area (CSA) as outcome measures. Magnetic resonance imaging (n = 22) and computed tomography (n = 8) were less frequently used but allowed for investigation of other geometrical measures such as vessel curvature and length. The venous system proved more sensitive to postural changes than the arterial system, which was seen as increasing diameters of veins below the level of the heart when going from supine to prone to standing positions, and vice versa.

CONCLUSIONS

The influence of body positions and postures on vasculature was predominantly explored with US for vessel diameter and CSA. Posture-induced deformation and additional geometrical features that may be of interest for the (endovascular) treatment of vascular pathologies have been limitedly reported, such as length and curvature of an atherosclerotic popliteal artery during bending of the knee after stent placement. The most important clinical implications of positional changes are found in diagnosis, surgical planning, and follow-up after stent placement.

CLINICAL RELEVANCE STATEMENT

This scoping review presents the current state and opportunities of position- and posture-dependent imaging of vascular structures using various imaging modalities that are relevant in the fields of clinical diagnosis, surgical planning, and follow-up after stent placement.

KEY POINTS

• The influence of body positions and postures on the vasculature was predominantly investigated with US for vessel diameter and cross-sectional area. • Research into geometrical deformation, such as vessel length and curvature adaptation, that may be of interest for the (endovascular) treatment of vascular pathologies is limited in different positions and postures. • The most important clinical implications of postural changes are found in diagnosis, surgical planning, and follow-up after stent placement.

Risk factors associated with venous thromboembolism in laparoscopic surgery in non-obese patients with benign disease

INTRODUCTION

Few studies have focused on intraoperative positioning as a risk factor for venous thromboembolism (VTE). Positioning that places the legs in a dependent position may be a risk factor. We theorized that the reverse-Trendelenburg position specifically would increase the risk of postoperative VTE.

METHODS AND PROCEDURES

374,017 subjects undergoing laparoscopic surgery in the 2015-2018 NSQIP database were included. Diagnosis of cancer and BMI ≥ 30 were excluded. Subjects were grouped based on positioning: reverse-Trendelenburg (RT), supine (S), and Trendelenburg (T).

RESULTS

The RT, S, and T groups consisted of 117,887, 66,511, and 189,619 subjects, respectively. Overall median BMI was 25.7, and 82.8% of subjects were non-smokers. VTE within 30 days postoperative was seen in 0.25% RT, 0.23% S, and 0.4% T (p < 0.0001); 30-day mortality was 0.34% RT, 0.25% S, and 0.19% T (p < 0.0001). After adjusting for potential confounders and other risk factors, RT position was associated with a lower risk of VTE compared to S (OR 1.49 with 95% CI 1.16, 1.93) and T (OR 1.34 with 95% CI 1.15, 1.56) positions. VTE risk was significantly different across the three groups (p = 0.0001). Inpatient procedures had a higher VTE risk vs outpatient (OR 2.49 with 95% CI 2.10, 2.95). Increasing operative time was associated with higher VTE risk [4th (> 106 min) vs 1st (≤ 40 min) quartiles (OR 3.54 with 95% CI 2.79, 4.48)].

CONCLUSIONS

Among other risk factors, inpatient procedures and longer operative times are associated with higher VTE risk in laparoscopic surgery performed for benign disease in non-obese patients. The risk was significantly different across the three positioning groups with lowest risk in the RT group and highest risk in the S group.

The Safe Practice of Female Genital Plastic Surgery

The purpose of this article is to guide surgeons in the safe practice of female genital plastic surgery when the number of such cases is steadily increasing. A careful review of salient things to look for in the patient's motivation, medical history, and physical examination can help the surgeon wisely choose best candidates. The anatomy is described, with particular attention given to the variations not generally described in textbooks or articles. Descriptions are included for labiaplasty, including clitoral hood reduction, majoraplasty, monsplasty, and perineoplasty with vaginoplasty. Reduction of anesthetic risks, deep venous thromboses, and pulmonary emboli are discussed, with special consideration for avoidance of nerve injury and compartment syndrome. Postoperative care of a variety of vulvovaginal procedures is discussed. Videos showing anatomic variations and surgical techniques of common female genital procedures with recommendations to reduce the complication rate are included in the article.

Preoperative femoral vein velocity in maximal flexion is a predictor of deep vein thrombosis in patients undergoing total hip arthroplasty

The aim of the study was to investigate if preoperative blood flow velocity in femoral vein in different positions of the hip during total hip arthroplasty (THA) is a predictor of postoperative deep vein thrombosis (DVT). In patients undergoing THA, blood flow velocity and diameter of proximal femoral vein on THA side were measured preoperatively in four flexion positions of the hip. After THA, patients were followed up for 42 days for DVT occurrence, and clinical features of patients with and without postoperative DVT were compared. The mean blood flow velocity in maximal flexion (90º+) preoperatively was significantly lower in patients with postoperative DVT (19/103) compared to patients without it (8.4±2 cm/s vs. 10.6±2.3 cm/s; p<0.001). Using the receiver operating characteristic curve analysis, the cut-off value for blood flow velocity during maximal flexion was 8.24 cm/s. In addition, anesthesia duration, duration of surgical position of the patient, body mass index, amount of blood transfused after surgery, and clinical signs of DVT were markedly different between patients with and those without postoperative DVT. Blood flow velocity in femoral vein in maximal flexion of the hip (90º+) measured prior to THA is an independent predictor of postoperative DVT.

Deep Vein Thrombosis in a Young, Healthy Baseball Catcher: A Case Report and Review of the Literature

Venous thromboembolism is becoming increasingly recognized as a significant cause of morbidity and mortality in the hospitalized pediatric population. However, young healthy athletes can present with unique risk factors for deep vein thrombosis (DVT) that can be overlooked. Here we report a case of an adolescent male with no inherited risk factors or prior history of DVTs who developed a right femoral vein DVT in the context of playing catcher in baseball after recovering from a bout of streptococcal pharyngitis. We review the evidence that suggests that repetitive squatting-induced compression of the femoral vein can cause the venous stasis and endothelial microtrauma that contributed to the formation of this thrombus.

Haemodynamic assessment in simulated operative positions before knee arthroplasty can be useful in deep vein thrombosis prediction

PURPOSE

During knee arthroplasty, the leg is placed in several forced positions, which are mainly uncomfortable for all tissue structures in the region, including the vascular structures. Veins have a weaker quality of the wall structure than arteries, so during the forced position morphological and haemodynamic consequences are expected mainly in the venous system. Conditions of safe aseptic environment for the arthroplasty are in collision with routine intra-operative analysis of local haemodynamics in real time. This is the reason why we have no insight into the haemodynamic and morphological changes at the time in which the initiation of deep vein thrombosis (DVT) occurs. For this reason we created the hypothesis that the monitoring of the occurrence and detection of potential DVT risks can be achieved pre-operatively using echosonograms in simulated operative positions, and then compare them with the cases of postoperative DVT.

METHODS

This research was conducted as a prospective, analytical, minimally manipulative and observational clinical study in the period January 2011 to October 2013. In the preoperative period we made ultrasound and colour-Doppler examinations of deep veins in simulated operative position (full extension 0°, semiflexion 30-60°, flexion 90° and maximal flexion 90°+). The target vein was the posterior tibial vein in the distal third of calf. During the operation we took a note of anaesthesia duration and forced positions duration. After the operation we were looking for ultrasound signs of DVT in a follow-up period of six weeks. The sample was made from 91 patients selected for knee arthroplasty: 56 women and 35 men patients of average age 67.46 years. The oldest patient was 81, and the youngest 48. Average body mass index was 26.98 (±2.20) kg/m(2). After initial ultrasound, the sample was divided into two groups according to vein flow velocity. Patients who had a flow velocity lower than 10 cm/s in any of the forced positions were in the investigated group (N-b, n = 38), and patients who had more favourable haemodynamics in forced positions were in the control group (N-a, n = 53). Patients underwent arthroplasty without tourniquet, and the operative, postoperative and anaesthesiological protocol was the same for all the patients.

RESULTS

Friedman's test results point out significant differences of posterior tibial vein flow velocity in four simulated positions (0°, 30-60°, 90°, 90°+). Overview of the median value of the posterior tibial vein flow velocity points out reduction of the posterior tibial vein flow velocity in the third and fourth simulated positions. Average range values were lowest in simulated position 90°+. Relative risk for the DVT occurrence was 21.6% higher in the group of patients with flow velocity lower than 10 cm/s with statistical significance. The incidence of DVT was higher in women (22.85%) than in men (14.28%). There was one (1.09%) case of pulmonary embolism (PE) presented as segmental PE.

CONCLUSIONS

We believe that preoperative ultrasound analysis performed during the simulation of operative positions is a useful pre-operative test that can identify patients at risk of developing postoperative DVT. We would recommend that during surgery procedure to minimise forced position of knee flexion.

Slow femoral venous flow and venous thromboembolism following inguinal hernioplasty in patients without or with low molecular weight heparin prophylaxis

BACKGROUND

Prosthetic material (mesh) is commonly used to repair inguinal hernias. Its implantation close to the common femoral vein (CFV) can induce slow flow and favor the appearance of venous thromboembolism (VTE) events.

AIM

To investigate the speed of flow, diameter and area of the CFV after inguinal hernioplasty.

METHODS

Two hundred and fifty patients receiving open hernioplasty with a non-resorbable mesh for the repair of a unilateral, primary, simple inguinal hernia were prospectively investigated. Patients were stratified, by consensus, into a low or a moderate risk of VTE group. The moderate-risk group (n = 163) received low molecular weight heparin. On day 10 post-operation a blinded Echo-Doppler was carried out, and repeated 7 days later in patients with a venous flow of <15 cm/s. The speed of flow (cm/s), diameter (cm), and area (cm(2)) of the ipsilateral and contralateral CFV of the groin operated upon were measured.

RESULTS

No event symptomatic of VTE was documented. One case of asymptomatic deep vein thrombosis (1/163, 0.6%) was found in the moderate-risk group. In 29 patients (2 and 27 in the low- and moderate-risk groups, respectively; p < 0.001) a maximum blood flow velocity of <15 cm/s was found in the ipsilateral CFV; these flows were close to normal in the second measurement. Taking the entire sample into account, the maximum venous blood flow found in the ipsilateral CFV of the operated groin was less than that measured in the contralateral CFV (20.88 vs. 24.01 cm/s; p < 0.001); this difference was significant in both VTE risk groups. The diameter and area of the CFV were both greater in the ipsilateral than the contralateral CFV (p < 0.01); this finding proved to be significant only in hernias of the left groin (p < 0.001).

CONCLUSIONS

In the immediate postoperative period, inguinal hernioplasty with mesh induces a temporarily slow venous flow in the ipsilateral CFV. However, this does not lead to an increase in the incidence of VTE.

Effects of patient position on lower extremity venous pressure during different types of hysterectomy

AIM

To explore the effects of different types of hysterectomy on lower extremity venous pressure.

METHODS

Ninety-nine patients with benign uterine diseases who were indicated for hysterectomy were included in the present prospective study. Patients were divided into three groups according to their preferences: (i) total laparoscopic hysterectomy (TLH) group (n = 36); (ii) transvaginal hysterectomy (TVH) group (n = 32); and (iii) transabdominal hysterectomy (TAH) group (n = 31). Lower extremity venous pressure was monitored using a pressure sensor during the surgery.

RESULTS

Compared with the supine position (TAH group, lower extremity venous pressure of intraoperative 16.50 cmH2 O), lower extremity venous pressure of the improved lithotomy position (TLH group, lower extremity venous pressure of intraoperative 53.27 cmH2 O) and conventional lithotomy position (TVH group, lower extremity venous pressure of intraoperative 42.09 cmH2 O) were significantly increased (P < 0.01).Venous pressure was reduced when patients lowered their heads by 15° or 5° in modified or conventional lithotomy positions, respectively (P < 0.01). Venous pressure was increased significantly after the establishment of pneumoperitoneum in the TLH group (P < 0.01).

CONCLUSION

Modified lithotomy position (TLH group) and conventional lithotomy position (TVH group) and CO2 pneumoperitoneum may result in increased lower extremity venous pressure during hysterectomy. Furthermore, elevated venous pressure can be altered by changing the intraoperative position. Specifically, intraoperative positioning of the lower extremities represents a modifiable risk factor for deep venous thrombosis.