SauFRa Technique for the Fixation of Resorbable Membranes in Horizontal Guided Bone Regeneration: A Technical Report

Guided bone regeneration (GBR) has become a gold standard in bone regeneration for localized ridge augmentation either prior to or in conjunction with implant placement. It is a well-documented technique in the literature that ensures repeatable and clinically predictable outcomes.^1–5  The GBR procedure involves the use of a space-maintaining scaffold in the form of a bone graft and blood clot, stabilized by a cell occlusive membrane. The membrane is pivotal in preventing ingression of epithelial or connective tissue cells into the recipient site. The membrane allows selective repopulation of the wound with osteoblasts, leading to bone regeneration.^6–9  PASS principle, that is, primary closure, angiogenesis, space maintenance, and stability of the wound and implant, has to be meticulously followed to achieve bone regeneration using GBR.¹⁰  Stabilization of the membrane and the graft is extremely crucial for successful GBR and has been traditionally accomplished using titanium tacks or screws.^11–15  Use of titanium tacks is fraught with the risk of damage to the adjacent tooth roots, and vital structures like inferior alveolar nerve and maxillary sinus.¹⁶  Furthermore, the placement of titanium tacks itself is discomforting to the patient, there exists a possibility of bending or breaking of the tip in the cortical bone and also requires a second-stage surgery for their removal. They also add to the cost of surgery and their loosening may lead to infection jeopardizing GBR.

The aim of this article is to describe the SauFRa technique, a novel technique for membrane stabilization in GBR using resorbable sutures, which can be thought of as a viable alternative to titanium tacks/screws and other membrane-stabilizing techniques.

A full-thickness trapezoidal mucoperiosteal flap with vertical-releasing incisions including the distal papilla of teeth on either side of the defect was raised. If implants were planned simultaneously with GBR, then implant placements were carried out. A horizontal periosteal-releasing incision was made 5 mm coronal to the base of the mucoperiosteal flap. Blunt dissection was carried out to expose the connective tissue and divide the periosteum into apical periosteum and coronal periosteum (Figure 1a). Such a maneuver helped in increasing the flap mobility and aiding in tension-free primary closure. Flap mobility was then checked by passively pulling the labial mucosa over the palatal/lingual mucosa. The authors were of the view that approximately 8–10 mm of overlap over the palatal/ lingual flap and approx. 5–6 mm beyond the grafted area was mandatory for a successful GBR procedure. Blunt dissection was accomplished posterior to the apical periosteum to separate the periosteum from the connective tissue and a pocket was developed. A bilayer resorbable membrane (Bio-Gide, Geistlich, Wolhusen, Switzerland) was then introduced anterior to the pocket and was sutured to the apical periosteum, using horizontal mattress sutures and making certain that the knot was tied toward the connective tissue. When performed in such a way, the periosteum was seen to overlap the membrane, thereby preventing apical extrusion of the graft. In all cases, 4-0 polyglactin 910 (Vicryl, Ethicon Inc, Somerville, NJ) with a 19-mm (FS-2) 3/8 circle reverse cutting needle was used. This was followed by decortication of the labial cortex using a 1-mm round bur to induce bleeding at the recipient site. A layered composite graft of autogenous scrapes, anorganic bovine bone mineral (Bio-Oss, Geistlich) and injectable- platelet rich fibrin (i-PRF) was placed. The membrane was then carried over the grafted area and was tucked underneath the palatal/lingual flap as apically as possible and sutured using horizontal mattress sutures while making certain that the knot was placed over the palatal/lingual mucosa. Lastly, 2 horizontal mattress sutures were placed bilaterally over the lateral extent of the membrane with knots over the palatal/lingual mucosa (Figure 1b and c). The suture was passed first through the palatal flap, then apically through the coronal portion of the connective tissue, and then continued through the palatal mucosa to complete the knot. This secured the membrane and prevented lateral displacement of the graft. These sutures also aided in fortifying the base of the labial flap, thus further decreasing the tension in the flap. Tension-free closure was achieved using horizontal mattress sutures over the crestal part of the flaps and interrupted sutures over the everted margins of the flap and vertical releasing incisions. The entire SauFRa technique is illustrated in Figure 2.

A total of 89 (51 males and 35 females) patients were operated using the SauFRa technique for membrane stabilization in GBR. This technique was employed for 44 cases in anterior maxilla, 23 in anterior mandible, 18 in posterior mandible, and 4 in posterior maxilla. The authors did not encounter any complications like tissue dehiscence, infection, or graft migration.

In the authors' view, the only challenge this technique poses in the posterior maxilla is the possibility of herniation of buccal pad of fat. A careful blunt dissection after periosteal release incision generally avoids this complication entirely. The authors did not encounter buccal fat pad herniation in the cases that they performed in posterior maxillary sites. The authors are of the opinion that even if the fat herniates, it will increase the duration of procedure marginally due to the need of additional isolation, but would not jeopardize the quality of the procedure in totality. However, for the purpose of illustration and ease of photographic documentation anterior maxillary and mandibular sites have been presented here.

Surgical site closure typically takes 20 minutes for this technique. To avoid the suture pulling through the periosteum, the operator should employ a single linear horizontal periosteal release incision, which should follow the entire width of the flap, and judicious blunt dissection should be performed to divide the periosteum into apical and coronal portions. Additionally, reverse cutting needles should be used and no undue forces should be applied. In the authors' experience duration for closure in the posterior sites gets prolonged by approximately 5 minutes.

Space maintenance, stability of fibrin clot, exclusion of epithelium and connective tissue, and primary wound closure form the pillars of PASS principle, which ensure successful GBR.¹⁰  This is achieved using a cell occlusive membrane that is biocompatible, adherent to tissues without mobility, prevents ingrowth of soft tissue, maintains space, and has good handling properties.¹⁷  Decortication allows blood vessels and osteoprogenitor cells to reach the recipient site, thus aiding in clot formation and eventually the healing process.^17–20  It also aids in integration of the graft and native bone as the graft scaffold is replaced by the bone regenerate.^17,21–23 

Resorbable membranes cannot hold its form in cases of vertical bone augmentation. The titanium-reinforced non-resorbable membranes are inevitable for vertical bone augmentation using GBR. However, the bio-inert non-resorbable membranes have a higher incidence of wound dehiscence and membrane exposure.¹⁷  The rigidity of the membrane also necessitates the need for additional membrane tacks. Furthermore, the patient needs an additional surgery for the removal of the non-resorbable membrane. This entails considerable discomfort and cost to the patient. Resorbable membranes on the other hand overcome all these disadvantages and have been the first choice among clinicians for horizontal bone augmentation using GBR. Many authors thus recommend the use of resorbable membranes in GBR.^11–13  Use of titanium tacks or resorbable pins or miniscrews for stabilization of resorbable membranes in GBR has shown well-documented evidence of formation of large bone volumes.^11–15  However, this technique is marred with potential risks such as damage to the adjacent roots and underlying anatomical vital structures, and the need for an additional surgery to retrieve the tacks.^24,25  Moreover, in our experience, placement of titanium tacks on the mandibular lingual cortex is extremely tedious and slippage of the tacks can lodge them deep into the lingual flap or floor of the mouth with their attendant complications.

Urban et al¹⁵  described the periosteal vertical mattress suture (PVMS) technique for membrane stabilization in single implant GBRs using resorbable bilayer collagen membrane. In this technique 2 vertical mattress sutures over the membrane were used to stabilize it. Sutures were passed through the apical periosteum and palatal periosteum, one on either side of the graft site. The authors recommended the PVMS technique for use in single implant sites. The authors mention that there is no control over apicocoronal migration of the graft in the PVMS technique. In addition to this, we are of the opinion that in the event of loosening of even one of the sutures in the first few weeks of wound healing, the graft could get laterally displaced and overall graft stability would be compromised, thus leading to failure of desired result from GBR. Shalev et al²⁶  described the continuous periosteal strapping sutures (CPSS) technique for multiple implant sites. In their technique they used multiple sutures to stabilize the membrane as well as CPSS technique sutures on the lingual/palatal flap. In our opinion such a technique can lead to failure of GBR if there is loosening of the key knot of the CPSS. Moreover, the final CPSS technique suture is tied to the short tail of the first knot, which can warp the membrane and the graft to the center of the total length of the membrane if fixed under tension or allow lateral migration of the graft if sutured loosely. The SauFRa technique on the other hand can be used in cases of multiple implant sites, anterior or posterior, maxilla or mandible, and has multiple checkpoints to ensure graft stability. The technique limits the apicocoronal migration of graft material with help of apical periosteum—membrane sutures along with membrane—palatal flap sutures (Figure 3a and b). Lateral migration of the graft is prevented by the connective tissue—palatal flap horizontal mattress sutures anchored to the resilient palatal flap, which provide double suture limbs on either side of the lateral aspect of the membrane that further enhances the graft stability (Figure 3c and d). These connective tissue-palatal flap sutures also have an added advantage of reduction in marginal flap tension similar to the suspended external-internal sutures described by De Stavola et al²⁷  and yet not compromise the vestibular depth. The only shortcomings of this approach are that it is technique sensitive and time-consuming compared to the use of tacks or miniscrews. The reduction in the tensile strength of the sutures during the healing phase may also be a point of concern.¹⁶  We concur with the authors of the CPSS technique in the use of 4-0 Vicryl. According to the manufacturer, Vicryl preserves 75% of its tensile strength at 2 weeks and 25% at 4 weeks as opposed to the loss of 75% of its tensile strength by 6-0 Monocryl (used by the authors in the PVMS technique). Despite lack of documented evidence, we agree with the authors of the PVMS and CPSS techniques that membrane stabilization may be required only for an initial few weeks until the preliminary bone matrix is formed.^16,26  This purpose is served better with 4-0 Vicryl than 6-0 Monocryl.

Hence, in our view, the SauFRa technique overcomes all the disadvantages posed by tack systems and other membrane stabilizing suture techniques described in the literature, thus becoming a viable alternative.

Membrane stabilization using titanium tacks or miniscrews in guided bone regeneration has been popular amongst most surgeons. However, the SauFRa technique can be thought of as a novel approach which relies on utilization of the horizontal periosteal release incision to its maximum potential in stabilizing the membrane and judiciously reducing the tension in the flap, both aided by the use of resorbable sutures. The authors' have not encountered any complications like tissue dehiscence or graft exposure for GBR using this technique in their clinical experience. The technique can be applied to single as well as multiple implants sites in both the maxilla and mandible. However, extensive clinical studies are required to validate this technique for predictable and repeatable bone regeneration.

Abbreviations

CPSS

continuous periosteal strapping sutures

GBR

guided bone regeneration

PVMS

periosteal vertical mattress suture

The authors would like to thank Miss Shreeja Mahambre and Mr Arunesh Mulay for the figure that illustrates this technique. The authors reported no conflicts of interest related to this study.

No potential conflict of interest relevant to this article was reported. An informed consent was obtained from all the patients and ethical approval was obtained from the Institutional Ethics Committee (GUACAD/ 4142).