Rectus abdominis muscle innervation: an anatomical study with surgical implications in diep flap harvesting

Rectus Abdominis Muscle Atrophy and Asymmetry After Pulmonary Lobectomy

INTRODUCTION

Pulmonary lobectomy can result in intercostal nerve injury, leading to denervation of the rectus abdominis (RA) resulting in asymmetric muscle atrophy or an abdominal bulge. While there is a high rate of intercostal nerve injury during thoracic surgery, there are no studies that evaluate the magnitude and predisposing factors for RA atrophy in a large cohort.

METHODS

A retrospective chart review was conducted of 357 patients who underwent open, thoracoscopic or robotic pulmonary lobectomy at a single academic center. RA volumes were measured on computed tomography scans preoperatively and postoperatively on both the operated and nonoperated sides from the level of the xiphoid process to the thoracolumbar junction. RA volume change and association of surgical/demographic characteristics was assessed.

RESULTS

Median RA volume decreased bilaterally after operation, decreasing significantly more on the operated side (-19.5%) versus the nonoperated side (-6.6%) (P < 0.0001). 80.4% of the analyzed cohort experienced a 10% or greater decrease from preoperative RA volume on the operated side. Overweight individuals (body mass index 25.5-29.9) experienced a 1.7-fold greater volume loss on the operated side compared to normal weight individuals (body mass index 18.5-24.9) (P = 0.00016). In all right-sided lobectomies, lower lobe resection had the highest postoperative volume loss (Median (interquartile range): -28 (-35, -15)) (P = 0.082).

CONCLUSIONS

This study of postlobectomy RA asymmetry includes the largest cohort to date; previous literature only includes case reports. Lobectomy operations result in asymmetric RA atrophy and predisposing factors include demographics and surgical approach. Clinical and quality of life outcomes of RA atrophy, along with mitigation strategies, must be assessed.

The Hypoechoic Triangle: A New Sonographic Landmark for Rectus Sheath Block

Rectus sheath blocks can provide analgesia for upper abdominal midline incisions. These blocks can be placed on patients who are anticoagulated, supine, and under general anesthesia. However, block success rates remain low, presumably because of the difficulty of placing local anesthetic between the correct fascial layers. Here we characterize a hypoechoic triangle with sonography, an anatomic space between adjacent rectus abdominis segments that can be accessed for easier needle tip and catheter placement. This approach could reduce reliance on hydrodissection to correctly identify the potential space and instead improve block efficacy by offering providers a discrete target for local anesthesia.

Reference Data on the Normal Abdominal Wall Anatomy and Baseline Characteristics in Seventy-One Nulliparous Women

Aims: The aim of this study was to describe the prepartum anatomy of the abdominal wall in a cohort of nulliparous women, for use as a reference for management of patients with postpartum abdominal wall insufficiency with or without rectus diastasis. Materials and Methods: Seventy-one women were examined with ultrasonography of the abdominal wall. The inter-recti distance (IRD), anatomical variations of the linea semilunaris, and the oblique muscles were assessed. The waistline was measured during activation and relaxation of the abdominal core. Participant characteristics were registered. Questionnaires regarding habitual physical activity (Baecke), low back pain (Oswestry), physical functioning (DRI), urinary incontinence (UDI-6 and IIQ-7), and quality-of-life (SF-36) were answered. Results: Mean age was 30.5 years (range 19-50 years) and mean BMI 23.5 kg/m2 (range 18-37). Ultrasonography showed a mean IRD of 10 mm (range 3-24) at the superior border of the umbilicus, 9 mm (4-20) 3 cm above the umbilicus, and 2 mm (-5-10) 2 cm below the umbilicus. The mean thickness of the linea alba was 3 mm (1.5-5) and mean distances between the lateral edge of the rectus muscle and the external, internal, and transverse oblique muscles were 12 mm (-10-28), 1 mm (-14-13) and 15 mm (-14-32) at umbilicus level. Responses to the DRI, UDI-6, IIQ-7 and Oswestry questionnaires showed generally lower scores than the normal population whereas Baecke and SF-36 scores were similar. Conclusion: This study provides baseline data on normal abdominal wall anatomy in a healthy nulliparous female cohort, as well as levels of activity, physical function, disability, and quality-of-life.

A New CT Analysis of Abdominal Wall after DIEP Flap Harvesting

The abdominal microsurgical flap based on the deep inferior epigastric artery perforator (DIEP) flap has become the most popular option worldwide for autologous breast reconstruction. Several authors have investigated the results of reconstructed breasts, but the literature lacks systematic reviews exploring the donor site of the abdominal wall. To fulfil our aims, a new diagnostic muscle imaging analysis was designed and implemented. This study focused on rectus abdominal muscle morphology and function in a single series of 12 consecutive patients analysed before and after breast reconstruction with a microsurgical DIEP flap. Patients were divided into two groups, namely, “ipsilateral reconstruction” and “contralateral reconstruction”, depending on the side of the flap harvest and breast reconstruction, then evaluated by computed tomography (CT) scans scheduled for tumor staging, and clinically examined by a physiatrist. Numerous alterations in muscle physiology were observed due to surgical dissection of perforator vessels, and rectus muscle distress without functional impairment was a common result. Postoperatively, patients undergoing “contralateral reconstruction” appeared to exhibit fewer rectus muscle alterations. Overall, only three patients were impacted by a long-term deterioration in their quality of life. On the basis of the newly developed and implemented diagnostic approach, we concluded that DIEP microsurgical breast reconstruction is a safe procedure without major complications at the donor site, even if long-term alterations of the rectus muscle are a common finding.

The Use of Semi-Absorbable Mesh and its Impact on Donor-Site Morbidity and Patient-Reported Outcomes in DIEP Flap Breast Reconstruction

BACKGROUND

This study aimed to evaluate the impact of semi-absorbable mesh on donor-site morbidity and patient-reported outcomes in deep inferior epigastric perforator (DIEP) flap breast reconstruction.

METHODS

We conducted a retrospective cohort study of all patients who had DIEP flap breast reconstruction in our department from July 2007 to March 2019. Patients were invited to a comparative follow-up visit and grouped according to donor-site closure: primary fascial closure (the no-mesh group) and fascial reinforcement with semi-absorbable mesh in a subfascial position (the mesh group). The primary outcome of interest was donor-site morbidity, including bulging, hernia formation and rectus abdominis muscle strength. We also surveyed, surgical site complications and patient-reported outcomes using Patient and Observer Scar Assessment Scale v2.0 and BREAST-Q^© version 2.0.

RESULTS

A total of 191 patients had received DIEP flap breast reconstruction. Eighty-five patients (44.5%) with 108 DIEP flaps (53 patients in the mesh group and 32 patients in the no-mesh group) were included in the study. The mean BMI of the patients was significantly higher in the mesh group (mesh group, 26.9 vs. no-mesh group, 25.0, with p = 0.03). The incidence of hernia was significantly reduced in the mesh group (mesh group, 2.8% vs. no-mesh group, 13.5%, with p = 0.03). The incidence of bulging and the extent of rectus abdominis muscle strength were similar for both groups. Operative surgical site complications were reduced in the mesh group (mesh group, 7.5% vs. no-mesh group, 18.8%). There was no difference in patients' physical well-being and satisfaction with the donor site between groups. Patient-reported scar outcome was significantly better in the no-mesh group (p < 0.001).

CONCLUSION

Our novel method of donor-site closure with semi-absorbable mesh in a subfascial position for reinforcement of the anterior rectus fascia on the DIEP donor site is safe. It has no negative impact on surgical site complications and patient-reported outcomes, while reducing the incidence of hernias on the donor-site in DIEP flap breast reconstruction.

LEVEL OF EVIDENCE IV

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Neurophysiological Changes in the First Year After Cell Transplantation in Sub-acute Complete Paraplegia

Neurophysiological testing can provide quantitative information about motor, sensory, and autonomic system connectivity following spinal cord injury (SCI). The clinical examination may be insufficiently sensitive and specific to reveal evolving changes in neural circuits after severe injury. Neurophysiologic data may provide otherwise imperceptible circuit information that has rarely been acquired in biologics clinical trials in SCI. We reported a Phase 1 study of autologous purified Schwann cell suspension transplantation into the injury epicenter of participants with complete subacute thoracic SCI, observing no clinical improvements. Here, we report longitudinal electrophysiological assessments conducted during the trial. Six participants underwent neurophysiology screening pre-transplantation with three post-transplantation neurophysiological assessments, focused on the thoracoabdominal region and lower limbs, including MEPs, SSEPs, voluntarily triggered EMG, and changes in GSR. We found several notable signals not detectable by clinical exam. In all six participants, thoracoabdominal motor connectivity was detected below the clinically assigned neurological level defined by sensory preservation. Additionally, small voluntary activations of leg and foot muscles or positive lower extremity MEPs were detected in all participants. Voluntary EMG was most sensitive to detect leg motor function. The recorded MEP amplitudes and latencies indicated a more caudal thoracic level above which amplitude recovery over time was observed. In contrast, further below, amplitudes showed less improvement, and latencies were increased. Intercostal spasms observed with EMG may also indicate this thoracic “motor level.” Galvanic skin testing revealed autonomic dysfunction in the hands above the injury levels. As an open-label study, we can establish no clear link between these observations and cell transplantation. This neurophysiological characterization may be of value to detect therapeutic effects in future controlled studies.

Correlations of the rectus abdominis muscle anatomy with anthropometric measurements

PURPOSE

The anterior abdominal muscle wall has a strong aesthetic connotation, primarily because of the classical anatomical description of the rectus abdominis muscle in the collective consciousness. However, the morphological reality of the general population considerably deviates from this description. Therefore, we investigated the anthropometric characteristics correlated with the anatomy of the rectus abdominis muscle.

METHODS

We performed a computed tomography scan anatomical study of recti abdominis muscles in 86 patients with no history of abdominal surgery. We noted the transverse and anteroposterior measurements of the rectus abdominis muscle, the transverse measurement of the linea alba, and the cutaneous and muscular abdominal perimeters. We compared these morphological elements with anthropometric data (sex, age, weight, height, and body mass index [BMI]).

RESULTS

BMI was positively correlated with cutaneous abdominal perimeter (r = 0.89, p < 0.001) and muscular abdominal perimeter (r = 0.7, p < 0.001). The correlation of BMI with cutaneous abdominal perimeter was not influenced by sex (r = 0.90 and r = 0.89 in men and women, respectively). The correlation of BMI with muscular abdominal perimeter was greater in men than in women (r = 0.80 vs. r = 0.75). The muscular abdominal perimeter was more strongly correlated with the transverse measurement of the rectus abdominis muscle in men than in women (r = 0.75 vs. r = 0.59). The muscular abdominal perimeter was more strongly correlated with the linea alba in women than in men (r = 0.51 vs. r = 0.31).

CONCLUSION

The anatomy of the anterior abdominal wall correlated with anthropometric data, including BMI. Rectus abdominis muscles and linea alba structures differed between men and women.

Contribution of Trunk Muscles to Upright Sitting with Segmental Support in Children with Spinal Cord Injury

To investigate and compare trunk control and muscle activation during uncompensated sitting in children with and without spinal cord injury (SCI). Static sitting trunk control in ten typically developing (TD) children (5 females, 5 males, mean (SD) age of 6 (2)y) and 26 children with SCI (9 females, 17 males, 5(2)y) was assessed and compared using the Segmental Assessment of Trunk Control (SATCo) test while recording surface electromyography (EMG) from trunk muscles. The SCI group scored significantly lower on the SATCo compared to the TD group. The SCI group produced significantly higher thoracic-paraspinal activation at the lower-ribs, and, below-ribs support levels, and rectus-abdominus activation at below-ribs, pelvis, and no-support levels than the TD group. The SCI group produced significantly higher lumbar-paraspinal activation at inferior-scapula and no-support levels. Children with SCI demonstrated impaired trunk control with the ability to activate trunk muscles above and below the injury level.

Abdominal wall sonography: a pictorial review

The anterior abdominal wall, which is composed of three layers (skin and adipose tissues; the myofascial layer; and the deep layer, consisting of the transversalis fascia, preperitoneal fat, and the parietal peritoneum), has many functions: containment, support and protection for the intraperitoneal contents, and involvement in movement and breathing. While hernias are often encountered and well reviewed in the literature, the other abdominal wall pathologies are less commonly described. In this pictorial review, we briefly discuss the normal anatomy of the anterior abdominal wall, describe the normal ultrasonographic anatomy, and present a wide range of pathologic abnormalities beyond hernias. Sonography emerges as the diagnostic imaging of first choice for assessing abdominal wall disorders, thus representing a valuable tool for ensuring appropriate management and limiting functional impairment.