Fixation-free Inguinal Hernia RepairUsing a Dynamic Self-retaining Implant

GIUSEPPE AMATO, MDCONSULTANT PROFESSOR

DEPARTMENT OF GENERAL AND EMERGENCY SURGERY

ANTONINO AGRUSA, MDRESEARCH FELLOW

DEPARTMENT OF GENERAL AND EMERGENCY SURGERY

GIORGIO ROMANO, MDASSOCIATE PROFESSOR

DEPARTMENT OF GENERAL AND EMERGENCY SURGERY

UNIVERSITY OF PALERMO, PALERMO, ITALY

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Hernia RepairSURGICAL TECHNOLOGY INTERNATIONAL XXII

Inguinal hernia repair remains controversial, despite advances in technique and materials. Conventional

implants are typically static (passive) and do not move in concert with the groin’s motility. Inguinal her-

nia repair with mesh fixation on dynamic groin structures are not tension free, and are associated with

tissue tearing, bleeding, hematoma, and nerve entrapment–all which might contribute to mesh dislocation.

The poor quality of tissue ingrowth within static meshes/plugs embodies another crucial issue in prosthetic

hernia repair. Because the prosthetics used for inguinal hernia repair are incorporated by rigid fibrotic tissue

(hence the term “scar plate”), the regressive tissue leads to shrinkage and reduction of the mesh surface

area–a significant cause of recurrence and discomfort.

To improve inguinal hernia repair, a new 3D dynamic (inherent recoil), self-retaining implant has been devel-

oped. It achieved excellent outcomes in the porcine model, and demonstrated that the dynamic compliant

movement and recoil of the 3D prosthetic structure within the groin’s natural tissues allowed for the critical

cyclical physiologic loading that is missing with other implants. Because enhanced biologic response and

improved quality of tissue ingrowth result from its dynamic interactions with groin tissue, the shrinkage of

the implant is nearly absent, even after long-term implantation. We discuss this dynamic hernia repair con-

cept in this report.

ABSTRACT

Inguinal hernia repair remains asource of passionate debate today.Despite advances in techniques andmaterials, high complication rates,patient discomfort, chronic pain, andrecurrence of hernia are associated withthe surgical procedure.1,2 The largevariety of techniques and materialsemployed in the treatment of inguinalprotrusions demonstrate that no goldstandard exists. Moreover, there is anoverall lack of current knowledge onthe pathogenesis of inguinal hernia; wehypothesize that this paucity of data isdue to the fact that the physiology andbiodynamics of the groin did not cur-rently warrant sufficient researchfund-ing, when compared to othercompetitively funded areas.Our group has undertaken an inte-

grated program of experimental andclinical study to define better the rangeof structural modifications that charac-terize the herniated groin. For example,histologic data from the examination oftissue samples excised from the groin ofliving patients and cadavers demonstrat-ed that inguinal protrusion was a conse-quence of a degenerative process(es)that affected muscle fibers, vessels, andnerves of the inguinal area; the resultwas progressive weakening the groinstructures that increased the risk forhernia.3-6 Our goal was to develop clini-cal strategies in hernia repair that incor-porated pathogenetic and physiologicconcepts, with a focus toward imple-menting techniques to impede the pro-gression of groin tissue degenerationand induce tissue regeneration.A current clinical dilemma is

whether static implants should be usedto treat a weakened motile barrier. Thedynamic structures of the herniatedinguinal region are currently managedwith static solutions, such as passive andmotionless meshes/plugs–a strategythat appeared to be at odds with thephysiology of the groin. Consequently,there was a high incidence of complica-

tions that were associated with the tech-niques employed to repair inguinal pro-trusions. For example, static implantswere often sutured or fixated withstitches or tacks on the myotendinealstructures of the groin, and fixation ofprosthetic devices was generally consid-ered to be sources of tissue tear, bleed-ing, hematoma, and nerveentrapment.2,7-10 It was hypothesizedthat an ideal implant should possessdynamic compliance and avoid fixation.Another factor is the low quality of

tissue ingrowth within the conventionalimplants employed to date. The stiffscar plate that typically resulted fromthe patient’s biologic response to staticimplants was considered the source oftissue shrinkage that ultimately reducesthe surface covered by the prosthesis.Hypothetically, this increased the risk ofrecurrence due to loss of coverage ofthe hernia defect by the shrunken mesh.Moreover, the disordered stiff, hard scartissue that incorporated the implant wasthought to involve nervous structuresthat resulted in patient distress and/orchronic pain over time. Notably, the dis-comfort upon movement described as“sand paper effect” resulted from fric-tion between the hardened, wrinkledimplant and the mobile myotendinealgroin structures. Thus, an enhancedbiologic response and superior qualityof tissue incorporation was anotherendpoint that we theorized might beimportant.We also believed that the widespread

approach that utilized flat meshes tocorrect defect coverage was inadequate.In anecdotal cases (especially in recur-rent direct hernias), despite the appar-ent correct placement of mesh, thevisceral protrusion still arose in theinterstitium between inguinal floor andthe overlying mesh. The clinical conse-quence was a bulge in the groin, con-comitant to discomfor t and pain.Therefore, we propose a dynamic (notstatic) treatment approach. In the fol-lowing sections, we describe devicesand procedures that characterized ourexperiences in dynamic hernia repair.

The implant system.The 3D dynamic compliant hernia

system was a dual system consisting of adisposable dilation and deployment toolof PVC, combined with a synthetic,permanent polypropylene 3D implant(ProFlor,™ Insightra Medical, Inc.,Irvine, California,) (Fig. 1). The implantpossesses a multi-lamellar shaped cen-tral core of specially worked polypropy-lene strips that are formed on 2 floatingrings to create an open 3D structurewith inherent recoil. The two edges ofthe petals are comprised of reinforcedpolypropylene that offers resiliency tothe structure. The lateral aspect of thecore is made of soft, lightweight, largeporous, polypropylene construction;this composition facilitates the grippingof the hernia border to the lateral aspectof the implant core. A flat, largeporous, low-weight polypropylene diskhelps protect the hernia repair and, fac-ing the peritoneum, stabilizes theimplant. The rationale of the implant’sunique 3D geometry is its ability totransform expulsion forces into lateralgripping forces.Two sizes (boxed together with their

respective delivery devices) are avail-able, as shown in Fig. 1:• 25-mm diameter core and 15-mm

thick implant with a flat disc of 60-mmdiameter, weighing 0.792grams.• 40-mm diameter core and 15-mm

tick implant with a flat disc of 70-mmdiameter, weighing 1.453 grams.The delivery device is composed of

smooth, transparent PVC (Fig.1), andcomprises a body with an enlarged distaledge (extremity; olive) that is intendedto dilate the hernia opening prior toimplantation. There is a flange on thedelivery device for a stop to indicate thedepth of penetration and prevent overinsertion, and a hollow section in theflange is intended as spermatic cordindicator that orients the implant. Aplunger is inserted at the proximalextremity of the device that can be

INTRODUCTION

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Fixation-free Inguinal Hernia Repair Using a Dynamic Self-retaining ImplantAMATO/AGRUSA/ROMANO

The use of this new 3D implant represented a faster and simpler surgical approach to inguinal hernia repair.

The procedure was based on the centrifugal expansion of the device, whose design features converted ejec-

tion forces into gripping forces, and avoided the need for suturing the implant (eliminating a cause of com-

plications related to prosthesis fixation).

MATERIALS AND METHODS

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turned in either block- or free-deliverymode by simply twisting the stab hori-zontally. The predilation of the herniadefect that is achieved by the enlargeddistal edge of the device helps augmentthe gripping action of the muscles andsimplify insertion of the prosthesis.

Procedural steps in indirect her-nia repair.After skin incision and opening of

the oblique interne aponeurosis, dissec-tion and elevation of the cord onto arubber band followed. This defined thehernia sac location and internal ring.(Explanatory comments are provided initalics.)• Removal of adhesions and scar tis-

sue. At this stage, meticulous removal ofadhesions and scar tissue around theinternal inguinal ring was performed.

This step was very important becausefibrosis and adhesion brides between thesack and internal inguinal ring impairedthe shutter mechanism of the muscularstructure of the ring.11 Therefore, adesiol-ysis helped to reactivate the sphincterialfunction of the internal ring. It was alsoimportant to avoid visceral protrusionwhen the abdominal pressure increased.• Preparation, ligation, and amputa-

tion of the sac. The next steps were:free preparation, high ligation, andamputation of the sac (Fig. 2).

Although hernia sac amputation is acontroversial strategy in static hernia

repair, it is recommended by some clini-cians.12,13 Sac amputation was a crucialmaneuver during our procedure thatincorporated the 3D dynamic implant. Infact, returning the entire hernia sack intothe per itoneal cavity might lead toimmediate or early recurrence if the pro-cedure is not carried out under certainconditions (ie, when the implant is toosmall for the hernia opening). Also, if thesack was cut off (and a small implantused), the flat sutured peritoneal sheathwould not re-form a sacculation for sev-eral weeks or months. During this period,the stabilizing properties of the preperi-toneal disk maintained the implant inplace, allowing tissue ingrowth withinthe dynamic implant. As a result, a defin-

Figure 1. The 3D dynamic self-retaining implant and delivery device. Twosizes are available: a 25-mm diameter core with a flat disc of 60-mm diame-ter, weighing 0.792 grams and a 40-mm diameter core with a flat disc of 70-mm diameter, weighing 1.453 grams. Both implant sizes have their respectivedelivery tools.

Figure 2. The hernia sac being amputated after high ligation.

Figure 3. Finger-guided dissection of the parietal peritoneum from the poste-rior abdominal wall to achieve space for deployment of the preperitoneal discof the implant.

Figure 4. The implant is compressed between the thumb and forefinger. Theimplant is inserted into the chamber of the delivery device while in this(squeezed) configuration.

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Fixation-free Inguinal Hernia Repair Using a Dynamic Self-retaining ImplantAMATO/AGRUSA/ROMANO

itive 1.5-cm thick barrier formed withina few weeks and impeded further protru-sion along the previous hernia gateway.• Finger-guided dissection. Before

releasing the sack stump into theabdominal cavity, we performed a fin-ger-guided dissection of the parietalperitoneum from the posterior abdomi-nal wall. The dissection achieved properplacement to accommodate the preperi-toneal disc of the implant (Fig. 3).

The dissection of the peritoneal sheathfrom the posterior abdominal wall (toachieve a broad space for the deploymentof the preperitoneal disk) was a manda-tory step. In addition to its stabilizingeffect facing the peritoneal sheath, thepreperitoneal disk was intended for poste-rior coverage of the Hesselbach’s triangle(to protect the fossa inguinalis mediafrom future direct hernia protrusion thatmight mimic a recurrence). The preperi-toneal disk, depending on implant size,has a radius ranging from 30 to 35 mm,and was large enough to cover the poste-rior aspect of the fossa inguinalis media.The maneuver was straightforward, andwas carried out in a short time period.Despite the presence of epigastric vesselsclose to the medial border of the internalring, injury to these vascular structuresdid not occur since they were readilydetachable from the peritoneal sheath.Note that this procedure was also feasiblethrough the use of other implants thatwere introduced trough the internal ring(to cover the posterior aspect of thegroin).• Preparation of the 3D implant. The

3D implant was at least 10-15% widerthan the hernia opening to ensure that

the prosthesis remained in the herniadefect through centrifugal expansionafter release into the hernia opening.The implant was compressed with thethumb and forefinger (Fig. 4) andinserted into the chamber of the deliv-ery device (Fig. 5). The implant coreremained compressed into the chamber,while the preperitoneal disk was fullydeployed outside the chamber (Fig. 6).During implantation, the plunger of thedevice was loaded by rotating it in blockposition until the detent stops rotation. • Positioning. The complex delivery

device containing the implant was posi-tioned into the hernia opening, withspecial care that the spermatic cord waspulled laterally from the hernia opening(for indirect hernia). The delivery toolwas then advanced into the herniaopening until its flange stopped againstthe muscular wall (Fig. 7). Additionalmoderate pushing/turning of the devicefacilitated better deployment of thepreperitoneal disk. The device wasslightly pulled back until no more com-pression was exerted, but remained intight contact with the ring. At thisstage, the plunger could be turned toejection mode and pressed topush/position the implant into thedefect; the preperitoneal disk remainedbeyond the hernia opening.

Because the olive ring of the implantwas larger than the hernia opening, theintroduction of the device provoked dila-tion of the muscular frame of the inter-nal ring that allowed the reactivation ofthe internal ring’s shutter mechanism–which might otherwise be blocked byfibrotic degeneration in indirect hernia

protrusion.3 The fibrotic fibers impairedthe sphincterial activity of the internalring, and dilation helped to break therigid fibers that impeded the movement ofthis muscular structure.11 The impairedshutter mechanism has been described as acommon pathogenetic factor for the etiol-ogy of indirect hernia.15-17• Implantation. After pushing the

plunger of the delivery device, theimplant was delivered into the herniaframe (and the empty tool was easilyremoved). The implant automaticallyexpanded into the hernia defect to fillthe gap completely. (Fig. 8) The roundlateral surface of the implant core mustbe positioned on the same plane of theinternal ring to achieve co-planar align-ment of the 3D implant to the anterioraspect of the hernia opening. The sper-matic cord must be positioned laterallyto the implant (Fig. 9).

If the leveling of the implant was notachieved during the initial attempt, asimple adjustment of the device wasachieved by gripping the small centralpolypropylene ring with forceps to movethe implant into the defect (Fig. 10).Occasionally, because a portion of thepreperitoneal disk remained outside thehernia defect, the disc edge was mechani-cally deployed beyond the opening by for-ceps.• Stress testing. At this stage, the pro-

cedure has been completed. Theimplant fully obliterated the herniadefect, and the preperitoneal disc inter-faced the peritoneum against the poste-rior aspect of the abdominal wall (Fig.11). To ensure the effectiveness of theself-retaining placement of the 3D

Figure 5. Insertion of the implant into the chamber of the delivery device. Figure 6. The implant is inserted into the chamber, and the preperitoneal discappears fully deployed outside the device while it advances into the herniaopening.

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Hernia RepairSURGICAL TECHNOLOGY INTERNATIONAL XXII

implant, the surgeon could apply astress test. If the procedure was per-formed under local anesthesia, thepatient was invited to cough. By cough-ing, the squeezing action of the internalring converted the ejection forces intogripping forces, and allowed theimplant to firmly grip the internal ring.In cases of procedures in general anes-thesia, the surgeon gripped the centralring of the implant core with forcepsand attempted to remove the implantwith moderate force.

During the stress tests, the implantcan be ejected after powerful coughs,shots, or a strong pull with forceps. Test-ing did not affect the effectiveness of theprocedure, since the implant bumped

against the sutured fascia and held thedevice in place after wound closure (dueto anteroposterior buffer effect). More-over, our experimental data in porcinedemonstrated that tissue incorporationoccurred within few hours, being that theimplant glued into the hernia opening bythe advancing tissue incorporation.18• After checking for hemostasis, the

external oblique was sutured. Skin clo-sure was subdermal, and avoidance ofwound drains occurred.

Procedural steps in direct herniarepair.• Dissection of the sac. After opening

the externus aponeurosis and elevatingthe cord onto a rubber band, a dissec-

tion of the sac from the groin structuresto the hernia opening in the fasciatrasversalis was performed. Removal ofany adhesions and scar tissue around thehernia opening was undertaken. • After full isolation of the hernia

sac, the trasversalis fascia was breached(as wide as necessary) to detach theperitoneal sacculation (with contents)around its posterior aspect. • Finger-guided dissection. A finger-

guided dissection (or mechanical adesiol-ysis with mounted pad) of the parietalperitoneum from the posterior abdomi-nal wall was performed to accommodatethe placement of the preperitoneal discof the implant. The released sack wasthen replaced into the abdominal cavity.

Figure 7. The delivery tool advances into the hernia opening until its flangestops against the muscular wall. Note that the hollow detent in the flangeindicates the optimal location of the spermatic cord (laterally of the device).At this stage, the plunger can be rotated in ejection mode, and the implant isdeployed into the hernia opening.

Figure 8. Delivery of the implant into the hernia opening. Centrifugal expan-sion enables fixation-free obliteration of the defect.

Figure 9. Indirect hernia repair. The implant obliterates the internal ring, andthe spermatic cord runs laterally in relation to the implant.

Figure 10. Direct hernia repair. By adjusting the device by gripping and mov-ing the small central polypropylene ring with forceps, the implant can also bepositioned into the defect.

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Fixation-free Inguinal Hernia Repair Using a Dynamic Self-retaining ImplantAMATO/AGRUSA/ROMANO

• Preparation of the 3D implant.Preparation of the 3D implant for deliv-ery into the hernia opening was per-formed as described above for indirecthernia.• Implantation. The delivery of the

implant was performed as describedabove for indirect hernia.• Positioning. Specific attention was

accorded to the deployment of thepreperitoneal disc to cover the internalring to avoid future protrusion of indi-rect hernia.• Stress testing. After positioning the

implant into the hernia frame, a stresstest was mandatory. If the procedurewas carried out under local anesthesia,the stress test was performed by invit-ing the patient to cough one or moretimes. If the procedure was performedunder general anesthesia, a stress testassessed the self-retaining behavior ofthe implant by having the surgeonslightly pull the implant outward bygripping the small central ring of thecore with forceps. Observations on stresstesting were applicable as noted for indi-rect hernia.• After checking for hemostasis, the

external oblique was sutured. Skin clo-sure was subdermal, and avoidance ofwound drains occurred.

Although treatment of inguinal pro-trusions includes one of the most com-mon surgical procedures performedtoday, neither the surgical communitynor industry has proposed/implement-ed significant changes in technique andmaterial for decades. Currently, no goldstandard exists, and high post-operativecomplication rates, and discomfort andchronic pain characterize its treatment.In an effort to utilize current and for-ward-looking concepts in the physiolo-gy/biodynamics of the inguinal region,pathogenesis of protrusion disease, andemerging technology, we have devel-oped an operative schema thatimproved patient outcomes in inguinalhernia repair.

We report a newly developed repairtechnique for the surgical treatment ofinguinal hernia. This technique incorpo-rated current physiologic concepts,pathogenesis, emerging devices, andnew procedures. The surgical commu-nity might utilize it as an additionaloption to improve and actualize thetechnical aspects of hernia repair proce-dures.

1. O’Dwyer PJ, Kingsnorth AN, Mohillo RG,et al. Randomized clinical trial assessingimpact of a lightweight or heavyweight onchronic pain after inguinal hernia repair. Br JSurg 2005; 92(2):166-70.2. Kim-Fuch C, Angst E, Vorburger S, et al.Prospective randomized trial comparingsutured with sutureless mesh fixation forLichtenstein hernia repair: long-term resultsHernia 2012;16(1):21-7.3. Amato G, Marasa L, Sciacchitano T, et al.Histological findings of the internal inguinalring in patients having indirect inguinal her-nia. Hernia 2009;13(3):259-62.4. Amato G, Ober E, Romano G, et a. Nervedegeneration in inguinal hernia specimensHernia 2011;15(1):53-8.5. Amato G, Romano G, Salamone G, et al.Damage to the vascular structures in inguinalhernia specimens. Hernia 2012;16(1):63-7.6. Amato G, Agrusa A, Romano G, et al.Muscle de generation in inguinal hernia speci-mens Hernia 2012;16 (3):327-31.7. Delikoukos S, Tzovaras G, Liakou P, et al.Late-onset deep mesh infection after inguinalhernia repair Hernia 2007;11(1):15-7.8. McCormack K, Scott NW, Go PM, et al.EU Hernia Trialists Collaboration. Laparo-scopic techniques versus open techniques foringuinal hernia repair. Cochrane DatabaseSyst Rev 2003;(1):CD001785.9. Grant AM. EU Hernia Trialists Collabora-tion. Laparoscopic versus open groin herniarepair: meta-analysis of randomised trialsbased on individual patient data. Hernia2002;6(1):2-10.10. Amato G, Sciacchitano T, Bell SG, et al.Sphincter-like motion following mechanicaldilation of the internal inguinal ring duringindirect inguinal hernia procedure. Hernia2009;13(1):67-72.11. Delikoukos S, Lavant L, Hlias G, et al.The role of hernia sac ligation in postoperativepain in patients with elective tension-freeindirect inguinal hernia repair: a prospectiverandomized study Hernia 2007;11(5):425-8.12. Stylianidis G, Haapamäki MM, Sund M, etal. Management of the hernial sac in inguinalhernia repair. Br J Surg 2010;97(3):415-9.13. Schumpelick V. in Hernien 4 AuflageThieme Verlag 2000;167-9.14. Flament JB. Funktionelle Anatomie derBauchwand. Chirurg 2006;(5):77:401-7.15. Stoppa R. Como se forma una herniainguinal? Actualizacion en chirugia del aparatodigestivo 1984-2004;(8):469-73;FundacionMMA.16. Read RC. Recent advances in the repair ofgroin herniation. Curr Probl Surg2003;40(1):13-79.17. Amato G, Lo Monte A I, Cassata G, et al.A new prosthetic implant for inguinal herniarepair: its features in a porcine experimentalmodel. Artificial Organs 2012;35(8):E181-E190.

Figure 11. Schematic representation of the implant obliterating an indirect hernia opening.

DISCUSSION

CONCLUSION

REFERENCES

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