Characteristics of the patients
Of 82 patients who were reviewed at the 6 clinical settings from January 2011 through November 2018, 45 were female who received 54 mesh placement procedures totally and 37 were male who received 53 procedures. These patients were all diagnosed with RAD combined with one or more hernia. The mean age undergoing first time hernia repair in males was significantly older than that of females (mean 61.2 years old vs. 49.2 years old, t = 4.654, P = 0.000). The mean BMI values were greater than 30 kg/m2 in both groups (mean 31.8 vs. 31.6, χ2 = 0.147, P = 0.883). The number of individuals smoking at index repair and using alcohol were high in both groups (37.8% vs. 31.1%, 54.1% vs. 48.9%, respectively) (Table 1).
The 5-year cumulative incidence of recurrence of and RAD and hernia was 37.0% in female group compared with 43.4% in male group (χ2 0.450, P = 0.557, Figure 1). While the recurrence after a one-year follow-up in male group was higher than in female group (24.53% vs. 5.56%, χ2 0.7.571, P = 0.007, Figure 1). We failed to identify risk factors contributing to recurrence after the repair with mesh when practicing binary logistic regression analysis by using 17 independent variables including age, race, concomitant conditions, mesh type, suture type, etc. As for the composite second outcomes, ventral hernia was most common type (27.8% vs. 40.7%, P = 0.104) and there was no difference in hernia number and type between two groups (P = 0.176). The rate of concomitant low back pain were higher than 30% as well in both groups (35.1% vs. 33.3%, P = 1.000), whereas depressive disorder and major depressive disorder in female group were significantly higher than that in male groups (51.1% vs. 27.0%, P = 0.041; 46.7% vs. 21.6%, P = 0.022, respectively). Over one-quarter cases had noted adhesion in abdominal cavity and there was no significant difference between two groups (29.7% vs. 35.6%, P = 0.641). Of 37 cases in male group, 20 (62.5%) had the history of open abdominal surgery compared to 33 of 45 cases (76.7%) in female group (P = 0.207) (Table 1). The most common anesthesia type was general anesthesia and the suture was used to close skin commonly in both groups (79.2% vs. 85.2%, 86.8% vs. 88.9%, respectively). In female group, risk of coexisting with low back pain in patients with pelvic and perineal pain was 27 times greater than that of those without pelvic and perineal pain (OR 28.653; 95% CI 2.924, 280.753; P =0.004); and patients with concomitant SMFT were more likely to have low back pain than those without SMFT as well (OR 9.604; 95% CI 0.763, 120.858; P =0.08).
Materials and Methods
This study was conducted according to the Modified Downs and Black checklist for randomized and non-randomized studies of healthcare interventions (DB) 25.
Systematic searches were conducted using Pubmed, Embase, and The Cochrane Library databases from the earliest data available to November 2018. The search terms used were “diastasis recti abdominis”, “diastasis recti”, “diastsis rectus abdominus”, “abdominal rectus diastasis”, “diastasis of the rectus abdominis muscle”, “linea alba”, “ diastasis recti and weakness of the linea alba”, and their combinations with Boolean “AND” and “OR” intervention terms, including “surgery”, “surgical intervention”, “reconstructive surgery”, “surgical treatment”, “prolotherapy”, “regeneration injection therapy”, “operative repair”, “abdominal wall repair”, “non-surgical intervention”, “conservative treatment”, physiotherapy”, “physical therapy”, “conservative management”, “conservative therapy”, “exercise”, “recommendation”, “counsel”, “manual therapy”, “strengthening”, “movement”, “fitness program”, “external support”, “band”, “tape”, “belt”, “tubigrip”, “drills”. There were no restrictions placed on study design, but only full texts in English were included. We performed also manually searched the included references of relevant papers to ensure full coverage.
Titles and abstracts were reviewed independently by three reviewers (Li YX, Fan L and Li Q) to determine the eligibility of the papers for inclusion. The research team discussed and resolved issues together if there were any disagreements. Studies meeting all the following criteria were included:1) the study included at least one intervention that aimed to improve RAD; 2) the study was designed as a prospective, retrospective, clinical trial, or case report; 3) Full-text journal articles in English. Cadaver studies and animal studies were excluded.
Data extraction and outcome measures
Outcomes of the systematic review were overall presence/absence of RAD, RAD size/width, patient satisfaction, recurrence rate, physical activity levels, back pain, functional impairments, quality of life, follow-up information, and adverse events. Data on the type of study and sample size, the nationality of the enrolled patients, and the patients’ age, sex, BMI (Kg/m2), the types of anesthesia used during the surgical operation were also extracted.
All included papers were evaluated for methodological quality using DB, which has a total maximum modified DB score of 28 and consists of four factors: external validity, confounders, bias, and power 25. Articles with a DB score were grouped into the following quality levels: strong (≥ 21), moderate (14-20), limited (7-13), or poor (7 or less) 26. The final set of papers varied in outcome reporting; therefore, a meta-analysis was not possible.
The initial database search yielded 3906 articles, and two were obtained by tracking the references. After removing 739 duplicates, 3169 studies were screened for further analysis. Since 3102 did not match the review criteria, 67 full-text articles were screened for eligibility; of these, 40 were excluded later. Therefore, 37 studies were included in this systematic review. The flow diagram and reasons for study exclusion are shown in Fig. 2.
Characteristics of the included studies
The characteristics of all 2372 patients from the 37 included studies are presented in Tables 1 and 211,12,17,20,22,27-58. 1341 (69.02%) patients in the surgery group and 422 (98.37%) patients in the non-surgery group were female; the gender of 607 patients was not reported. BMI was reported in 20 studies (the average BMI was > 23 kg/m2 in each reported study). There are four randomized controlled trials in the non-surgery group and three prospective clinical trials in the surgery group.
Of the studies examining surgery intervention, 11 were of moderate quality, 13 were of limited quality, and three were of poor quality; of the studies examining non-surgery intervention, four were of strong quality, four were of moderate quality, and two were of limited quality. The average modified DB score of the included studies for the surgery intervention group was 11.7 (range 6-20), and that for the non-surgery group was 18.4 (range 12-26).
Type of anesthesia
Fifteen studies described the type of anesthesia, ten used general anesthesia, two used local anesthesia, and three used general anesthesia combined with epidural anesthesia. There were no complications due to anesthesia reported in any of the included studies.
Eight studies (29.63%) reported the use of endoscopy during abdominoplasty surgery; the remaining studies (70.37%) were performed using a vertical skin incision from the xiphoid process to the umbilicus or a low transverse skin incision. The mesh augmentation technique was used to reinforce the linea alba with or without associated hernias in nine studies (33.33%), and the type of mesh used included polypropylene, self-adhesive synthetic, composite, and resorbable vinyl mesh.
In eight studies (29.63%), liposuction was combined with traditional abdominoplasty and repair of the rectus sheath defect to reduce complications and provide fast recovery; the volume of abdominal lipoaspirate ranged from 50 to 2800 ml, and the maximum volume reported in these studies was 7800 ml. Five studies (18.52%) reduced recurrence by adopting a special suture method, such as the triangular mattress suture, continuous suture, the Venetian blinds application technique, braided suture, buried suture, and figure-of-eight suture combined with the wearing of self-adherent silicone strips.
Muscle strength training, such as training of the pelvic floor muscles, abdominal muscles, rectus abdominis, internal/external oblique, or transverse abdominal muscles, was performed in all included non-surgery studies. Physical interventions including head lift, pelvic lock or tilt, plank, superman, and double leg raise were induced into the intervention program in two studies. The frequency was from one to 14 times per week, and the period of intervention was from 8 weeks to 15 months unequally.
The conclusions from six studies (60%) in the non-surgery group were positive, and the remainder (40%) were negative. The indexed outcomes included one or more of the following: inter recti distance (IRD), BMI, abdominal strength, pain, quality-of-life (QOL), pelvic floor distress index (PFDI), and activation endurance (hold seconds). In the surgery group, 26 studies (96.30%) obtained positive results over the short-term, and just one study (3.70%) reported negative results over the long-term. The indexed outcomes in this group included one or more of the following: the width of the diastasis of the recti abdominis muscles, ventral hernia pain, quality-of-life, Oswestry Disability Index, abdominal wall function, cosmetic outcome, satisfaction, Aponeurosis Shortening Index (ASI), back pain after surgery, and recurrence rate. None of the included studies demonstrated that physical training can be effective in improving the abdominal wall function of patients suffering RAD combined with hernia.
In the surgery group, there were seven studies (25.93%) including a total of 603 subjects with a reported follow up of 12 months; no patient relapsed; after a follow up of 24 months, the three remaining studies (11.11%) reported a 0% recurrence in a total of 268 subjects. Van reported a 40% recurrence rate of standard plication of the abdominal wall with absorbable material after a follow up of 5 years in a retrospective study of 40 patients attending a follow-up ultrasound investigation and with a total sample size of 70 women. No residual or recurrent diastasis was reported among 228 subjects receiving experimental training in the non-surgery group.
Twenty-four studies (85.19%) including a total of 1989 patients described adverse events associated with the surgery, which included: seroma (102 cases, 5.13%), sensibility disorder of the abdominal skin (45 cases, 2.26%), minor scar (31 cases, 1.56%), necrosis (umbilical/skin/sterile/infected fat) (19 cases, 0.96%), pain (13 cases, 0.65%), wound infection (13 cases, 0.65%), dog-ears (9 cases, 0.45%), hematoma (8 cases, 0.40%), sensibility disorder of the thigh (6 cases, 0.30%), epigastric fullness (4 cases, 0.20%), full-thickness skin loss (3 cases, 0.15%), prolonged neuralgia (3 cases, 0.15%), thrombosis (3cases, 0.15%), discrete wound (3 cases, 0.15%), subcutaneous emphysema (2 cases, 0.10%), transient scalp alopecia (1 case, 0.05%), pulmonary embolism (1 case, 0.05%), pneumonia (1 case, 0.05%), subdermal burn (1 case, 0.05%), epidermolysis (1 case, 0.05%), and postoperative ileus (1 case, 0.05%). There were no adverse events reported in patients with physical training.