Intra-abdominal pressure changes following incisional
hernia repair with heavyweight versus lightweight meshes
Thesis
Submitted for partial fulfillment of M. D. degree in general
surgery
By
EMAD AZIZ ELDIEN HABIB NACHLA
MBBCH
M.Sc
Under supervision of
PROF. DR.
ABDEL-MOTY HUSSEIN
Professor of General Surgery
Faculty of Medicine
Cairo University
PROF. DR.
MOHAMAD ESSAM ELKOUSY
Professor of General Surgery
Faculty of Medicine
Cairo University
PROF. DR.
MOHAMAD AMRO ABDEL-FATAH MATAR
Professor of Anesthesia
Faculty of Medicine
Cairo University
Faculty of Medicine
Cairo University
2210
Acknowledgement
I wish to express my sincere gratitude, deep thanks and appreciation to Prof. Dr. Abdel-Moty Hussein, Professor of General surgery, faculty of medicine, Cairo University for his constant encouragement, diligent advice and guidance as well as for his supervision and infinite patience in following up this work in all its stages.
A special debt of gratitude is owed to Prof. Dr. Mohamad Essam EL-Kousy, professor of general surgery, faculty of medicine, Cairo University whose extensive help, guidance and supervision could not be measured in acknowledgement, to whom I can not find adequate words.
I feel especially indebted and extremely grateful to Prof. DR. Mohmad Amro Abdel-Fatah Matar,
Professor of Anesthesia
, faculty ofmedicine, Cairo University for his continuous encouragement and helpful suggestions during the course of this work.
Finally thanks are extended to all those who participated in one way or another in making this work possible.
Abstract
This study was performed to assess and compare the effect of different types of meshes (lightweight and heavyweight) on intra abdominal pressure and ventilatory pressures. Sixty cases with incisional hernia divided into two groups (lightweight versus heavyweight) were studied in the period between March 2006 to October 2011. Intracystic pressure was measured as an indicator for intra abdominal pressure. It was concluded that there was no intraoperative or early post operative difference as regard increased intra abdominal pressure between the two groups.
Keyword: Incisional Hernia Abdominal Compartment Syndrome -incisional hernia repair- HWM
List of contents
Introduction and aim of the work 1
Incisional hernia Introduction 3
Pathogenesis of incisional hernia 5
Clinical presentation and diagnosis 9
Classification of incisional abdominal wall hernias 10
Type of incisional hernias repair 19
Non prosthetic repairs 19
Prosthetic repairs 20
Onlay (overlay) technique 21
Inlay (bridging) technique 23
Preperitoneal (sublay) technique 24
Components’ separation technique 26
Laparoscopic incisional hernias repair 28
Surgical mesh Introduction 30
History of mesh repair 30
Classification of biomaterials used for hernia surgery 31
Surgical mesh and technology 32
Integration into the abdominal wall: biocompatibility and foreign body reaction 36
Physiological Reconstruction 39
Abdominal Wall Compliance 43
Mechanical Testing for mesh Burst Strength 51
Mechanical Testing for mesh Stiffness 53
Mesh shrinking 55
Different mesh biomaterials and related complications 61
intraabdominal pressure Introduction & Incidence 75
Recognition of the abdominal compartment syndrome 75
Normal intraabdominal pressure and Etiology of intraabdominal hypertension 79
Classification of IAH 80
High risk groups and risk factors 80
Diagnosis of IAP 81
Clinical and radiological examination 82
Measurement of IAP 85
Measurement of IAP via a transurethral catheter 86
Measurement of IAP via the Stomach 92
Intraabdominal pressure monitoring techniques 98
Measurement of IAP via Rectal pressure 101
Pathophysiology 106
Intra-abdominal pressure and associated hemodynamic monitoring errors 106
Pulmonary impact of intra-abdominal hypertension 110
Intra-abdominal hypertension and Abdominal wall 116
Intra-abdominal hypertension and the gut 118
Intra-abdominal hypertension and Hepatobiliary system 121
Intra-abdominal hypertension and Ophthalmic changes 121
Intra-abdominal hypertension and Lower Limb Effects 122
Intra-abdominal hypertension and Nervous system 122
Intra abdominal hypertension and MODS 125
Patients and Methods 128
Results 133
Discussion and conclusions 151
Summary 155
References 157 Appendix
List of Figures
Figurenumber
Title Page
1 A-Upper midline incision (case No. 15 group B). B-lower midline incisional hernia (case No.12 group A).
4
2 Classification of midline incisional hernias 12 3 Classification of lateral incisional hernias 13 4A Definition of the width and the length of incisional
hernias for single hernia defects and multiple hernia defects
17
4B intra operative measurement of hernia defect (Case No. 3 group B)
17
5 Herniation of large content (A)through small hernia defect(B).
18
6 Positions for Placement of a prosthesis for repair of venteral abdominal wall defects.
21
7 onlay placement of surgical mesh using light weight mesh (A) and heavyweight mesh (B)
23
8 Position of surgical mesh in sublay technique 25 9 Different positions for the mesh in sublay technique 25 10 components separation technique 27 11 Illustration of Laplace’s Law 40 12 Abdominal muscle anatomy 44 13 Main loading direction of anterior abdominal wall 45
14 Reduced abdominal curvature after repair with different type of meshes
46
15 Elasticity of different mesh materials at 16 N 49 16 Principle of 3D-stereography 50 17 Mechanical Testing for mesh Burst Strength 52 18 Burst load data for HW, MW, and
LW meshes after implantation.
52
19 Stiffness measurements calculated for HW, MW, and LW meshes
54
20 Scar plate formation in HWM and LWM. 58 21A HWM, 90 days post implantation with fold
development.
58
21 B LWM, 90days post operative implantation with fold-free incorporation.
58
22 A scar plate covering the whole HWM. 59 22 B Localized fibrotic reaction around mesh fibers with
small granuloma in LWM.
60
23 Incisional hernia following mesh repair (recurrence at the mesh margin)
62
24.A CT image shows inferior vena cava is collapsed 84 24.B CT image shows severe pancreatic ascites. Ratio of
maximum anteroposterior girth to lateral abdominal girth is 0.80
84
24.C Bowel walls are thickened and show increased enhancement
84
26 Indirect measure of intra-abdominal pressure 89 27 A closed, needle-free intravesical pressure 91 28 Measurement of IAP via the stomach 93 29 Oesophageal balloon catheter for measuring intra
abdominal pressure.
95
30A IAP- Air-pouch catheter 97 30B Air-pouch catheter connected to integrated IAP
monitor
97
31 IAP using Foley manometer 100
32 Microchip transducer 102
33 Respiratory effects of IAH 113 34 The impact of neuromuscular blockade on patients
with intraabdominal hypertension
124
35 A Pathophysiology of the abdominal compartment syndrome
126
35 B vicious cycle leads to MOD 127
36 Visual Analogue Scale 131
37 . Range of age between the two groups 134 38 Gender distribution in group A 135 39 Gender distribution in group B 135 40 Body mass index distribution. 136 41 patient’s co-morbidities 138 42 Classification of incisional hernia in studied cases. 140 43 size of hernia defect within the studied cases 141
45 Post operative hospital stay in each group 145 46 Degree of pain between the two groups using VAS 147
List of Table
Table No. Item Page
1 European Hernia Society classification for incisional abdominal wall hernias
18
2-A Age of the studied cases 133
2-B Age of studied groups 134
3 Gender of the patients 135
4 Body mass index 136
5 Statistical study of BMI for studied groups 137 6 Patients co-morbidities 137 7 classification of incisional hernia 139 8 Size of hernia defect within the studied cases 141 9 size of mesh used in the studied groups 142 10 Intra operative airway pressure changes in group A 143 11 Intra operative airway pressure changes in group B 143 12 Intra cystic pressure changes in group A (intra
operative measurements)
144
13 Intra cystic pressure changes in group B (intra operative measurements)
144
14 Post operative hospital stay 145
15 Time of surgery 146
16 degree of pain 147
17 Post operative intracystic pressure. 148
Table of Abbreviations
Abdominal Compartment Syndrome ACS Abdominal Perfusion Pressure APP Acute Respiratory Distress Syndrome ARDS
Central Venous Pressure CVP
Cerebrospinal Fluid CSF
Computerized tomography CT
Expanded Poly-Tetra-Fluoroethylene ePTFE
Filtration Gradient FG
Foreign Body Reaction FBR
Global End-Diastolic Volume GEDV
Heavyweight Mesh HWM
Intensive Care Unit ICU
Interleukin-1-Receptor-Antagonist IL-1-RA Intra Abdominal Pressure IAP Intra-Abdominal Hypertension IAH Intra-Abdominal Pressure IAP
Intra Cranical Pressure ICP
Intravesical Pressure IVP
Lactate Dehydrogenase LDH
Lateral L
Lightweight Mesh LWM
Liver Function Test LFT
Matrix MetalloProteinase MMP
Mean Arterial Pressure MAP
Middleweight Mesh MWM Multiple Organs Dysfunction Syndrome MODS
Newton/cm N/ cm Polyethylene-Terephthalat PET Polyglactin 910 PG 910 Polyglecaprone 25 PG 25 Polymorph Nucleocyte PMN Polypropylene PP Polyvinylidenflourid PVDF
Positive End Expiratory Pressure PEEP
Post Operative Day POD
Pound per Square Inch PSI
pound-Force per Square Inch Ib/in² Pulmonary Artery Occlusion ("wedge") Pressure PAOP
Recurrences R
Renal Function Test RFT
Right Ventricular End-Diastolic Volume RVEDV
Short Form-36 SF-36
Species spp
Standard Deviation SD
Statistical Package for Social Sciences SPSS
Stroke Volume Variation SVV
Systemic Inflammation Response Syndrome SIRS
Tension T
Tumor Necrosis Factor TNF
Versus Vs
Width W
World Society on Abdominal Compartment Syndrome
Introduction
1
Introduction
Incisional hernia is a complication in 11 - 20 % of patients after laparotomy and some of these complications requiring emergency surgery (Conze et al., 2005). Repair of incisional hernia is a frequent operation in surgery with recurrence rates between 14 – 50 % with traditional repair and between 0 – 10 % with mesh repair (Welty et al., 2001).
Despite the broad acceptance of meshes in hernia surgery, certain physical properties of mesh biomaterials can lead to undesirable consequences. These include infection, seroma formation, bowel obstruction, fistula, mesh migration, failure of repair or restriction of the abdominal wall elasticity (Klinge et al., 1999).
These complications have been the rationale to investigate the biocompatibility of meshes. As a consequence, two major mesh concepts are distinguished, the classic concept including so called heavyweight meshes and the new concept including lightweight meshes. Lightweight composite mesh is the result of incorporating an absorbable component into a reduced polypropylene mass (Klosterhalfen et al., 2005).
The normal pressure inside the abdomen is atmospheric and varies inversely with intrathoracic pressure during normal spontaneous ventilation (Kron et al., 1984). Intra-abdominal hypertension exists when intra-abdominal pressure exceeds a measured numeric parameter. This parameter has generally been set at between 12 and 25 mmHg. Abdominal
Introduction
2
compartment syndrome exists when intra-abdominal hypertension is accompanied by manifestations of organ dysfunction (Ivatury et al., 1997).
Elevated intra-abdominal pressure has effect on pulmonary function in the form of reduction of the total lung capacity and residual volume. Progressive elevation of intra abdominal pressure leads to hypoventilation with hypoxia, hypercapnia and increase ventilatory pressure especially after repair of large hernias in obese patients (Kron et al., 1984).
Flexible lightweight mesh with similar elasticity to the abdominal wall, can deal with the increased pressure than heavyweight meshes with low elasticity. Restriction of the abdominal wall elasticity is one consequence of the implantation of heavyweight meshes with low elasticity (Klinge et al., 1996).
Surgery of giant incisional hernias is still challenging as regard the choice of surgical technique, the prosthesis and method of fixing (Klinge et al., 2005).
Aim of work
The aim of our work is to compare heavyweight and lightweight mesh repair of incisional hernias as regard their effect on the intra-abdominal and ventilatory pressures. Statistical analysis of the collected data with analysis of variance will be used to examine the effect of repair of incisional hernia and the significant difference (p < 0.05) between results from the two groups.
Review of literature Incisional hernia
3
Introduction
Incisional and ventral hernias account for 10% of all hernias. Surgery of giant abdominal incisional hernias is still challenging (Fig.1: A& B). Approximately 200,000 incisional hernia repairs are performed each year in the United States, making incisional hernia formation the most common indication for reoperation after laparotomy (karem and Michael, 2010). Postoperative reduction of abdominal girdle and repositioning of viscera suddenly increase the pressure inside the abdomen (Matthews and Neumayer, 2008).
The aim of preventing recurrences very often requires the use of a prosthesis, which must be placed on a low-tension environment to avoid early failures and an excessive increase of intra-abdominal pressure (De Santis et al., 2003).
Laparotomy performed for surgical access usually heals quickly and without complications, leaving a stable scar. Despite continual movement of the abdominal wall, intra-abdominal pressure peaks of up to 180 mmHg and local suture tensions of up to16 N/cm2, the sutured abdominal walls heal within a few weeks to form a solid scar that is comparable in stability to healthy abdominal walls (Schumpelick et al., 2006).
In bursting experiments, the abdominal wall scars are not sites of selectively increased rupture risk, but are as strong as normal abdominal wall tissue. This is the norm. An exception to this is the rare (< 1%)
Review of literature Incisional hernia
4
occurrence of acute separation of the sutured abdominal walls during the postoperative phase – known as acute wound dehiscence or burst abdomen – and the more frequent (> 20%) occurrence of chronic wound dehiscence with the formation of a hernial sac and canal months to years after surgery (Schumpelick et al., 2006).
In 1804 Astley Cooper stated that, hernia is a protrusion of any viscus from its proper cavity. The protruded parts are generally contained in a sac-like structure, formed by the membrane with which the cavity is naturally lined (Eubanks, 1997).
Incisional hernia definition proposed by Korenkov et al., 2001 as; any abdominal wall gap with or without a bulge in the area of a postoperative scar perceptible or palpable by clinical examination or imaging within one year of the index operation.
Fig.1: A- Upper midline incision (case No. 15 group B). B- Lower midline incisional hernia (case No. 12 group A).
B A
Review of literature Incisional hernia
5
Pathogenesis of incisional hernia
Several clinical studies reported that incisional hernias occur up to 10 years after surgery. These studies gave reason to believe that a well-healed abdominal wound can weaken over the course of years and then give rise to incisional hernia (Franchi et al., 2001and Burger et al., 2005).
The development of an incisional hernia is multifactorial. There are two major areas which influence its pathogenesis: surgical technique, and patient-related factors.
A-Surgical technique
Most retrospective studies looking at surgical technique as a possible influence of incisional hernia risk have focused on (1) the type of incision, (2) type of suture material, (3) and suture technique.
(1) Type of incision:
A retrospective study reported that the incidence of incisional hernia found to be more common following midline incisions (10.5%) when compared with transverse incisions (7.5%), Pfannenstiel incisions and pararectal incisions (2.5%) (Carlson, 1997), However a randomized controlled trial evaluating midline versus transverse incisions found no difference between either approaches at the one year follow up as regard recurrence (Seiler et al., 2009).
Review of literature Incisional hernia
6
(2) Type of suture materials:
Several meta-analyses report the lowest incidences of incisional hernia for monofilamentous, nonresorbable or long-term resorbable suture materials (Rucinski et al., 2001). Nonabsorbable suture materials have the advantage of longevity than absorbable suture material, but are more likely to result in sinus formation and chronic wound pain due to permanent mechanical tissue irritation (Hodgson et al., 2000).
(3) Regarding wound closure
Cleveland et al., 1989 reported that no difference in the incidence of dehiscence or hernia formation when either continuous or interrupted technique is used. However meta-analyses by Hodgson et al., 2000 support the use of a continuous suture technique. The only theoretical disadvantage of continuous closure is that the security of the wound is dependent on a single strand of suture material and a limited number of knots (Rucinski et al., 2001).
In 1976 Jenkins proposed a "precise surgical suture technique" His proposed suture length to wound length ratio of 4: 1 has since been investigated in both experimental and clinical studies (Hoer et al., 2000). Other technical factors such as slippage of knots, suture fractures or excessive tension can result in incisional hernia formation (Sanders and Di Clementi, 1977).
