Implants placed in fresh extraction sockets, referred to as immediate implants, are a unique clinical challenge with a higher complexity and therefore a higher poten tial for complications. The most common complications associated with immediate implants are discussed in this section, with guidelines on prevention and management. The concepts and guidelines of prevention and management of implant complications still apply; only the complications unique to immediate implants will be discussed in this section.Immediate implant failure
While immediate implants have a high survival rate, several studies show higher failure rates compared to more delayed implant placement protocols. A meta‐ analysis of seven randomized controlled trials com paring immediate implants with immediate‐delayed implants and delayed implants did not show statisti cally significant differences of implant survival bet ween the groups, but several preliminary conclusions were made that were not statistically significant, including a possibly higher implant failure rate in the immediate group (Esposito et al., 2010). Individual randomized controlled trials either show no difference in implant survival (Siegenthaler et al., 2007) or a higher failure rate with immediate implants (Schropp et al., 2005; Lindeboom, Tjiook, and Kroon, 2006), with implant survival rates of as little as 91% in these studies. A cross‐sectional analysis also identified immediate implant placement as a risk factor for implant failure (Daubert et al., 2015).
Prevention
Although survival of the immediate implant is high, several studies show higher failure rates of immediate implants. Therefore, prevention of this complication encourages the use of a nonimmediate implant placement protocol.
The following list of requirements for success has been published for the prevention of complications with immediately placed implants (Wagenberg and Froum, 2010): (i) removal of all infectious material from the socket, (ii) adequate available bone and soft tissue, (iii) initial implant stability, (iv) patient cooperation with postsurgical maintenance, (v) apical or lateral stabiliza tion, (vi) residual infection removed, (vii) careful deter mination of patient expectations, and (viii) consideration of final outcome after healing.
Midfacial gingival recession in the anterior maxilla
A systematic review by Chen and Buser (2014) showed that esthetic outcomes are achievable with immediate implants in the anterior maxilla, but the esthetic results are more variable, and there is a higher frequency of midfacial recession than implants placed in a delayed fashion. A literature review showed 0.5–0.9 mm of midfacial gingival recession with immediate implant placement (Chen and Buser, 2009).
Risk factors
The two major risk factors identified in midfacial reces sion are buccal implant positioning and thin periodontal biotype (Chen et al., 2009). Buccal malposition of the immediate implant is a possibility because the extrac tion socket, which is more buccal than the ideal placement of the implant, tends to push the osteotomy and the implant into the empty socket.
Proper diagnosis and treatment planning can prevent poor esthetic outcome. The following factors are impor tant to consider: medical status, smoking habit, patient’s esthetic expectations, lip line, tissue biotype, shape of tooth crowns, infection at implant site, bone level of adjacent teeth, restorative status of neighboring teeth, width of edentulous span, soft tissue anatomy, and bone anatomy of alveolar crest.
Prevention
Ideal implant position in the anterior maxilla is palatal to the incisal edge, which will result in thicker hard and soft tissue buccal to the implant (Figure 7.14) and a slight buccal cantilever to the restoration.
Prevention first involves presurgical treatment planning with a three‐dimensional imaging that shows the volume and position of the bone. The clinician must decide before extraction whether an immediate implant can be stabilized in an ideal position. Ideally, an immediate implant in the anterior maxilla will have 5 mm of bone apical to the extraction socket to stabilize the implant.
If an implant can safely be placed into an extraction socket, the use of a tapered implant can allow for easier angulation of the implant for proper palatal emergence of the head of the implant. The narrower apex of the tapered implant reduces the incidence and severity of fenestration of the bony concavity of the anterior max illa during the osteotomy, and it increases the primary stability of the implant.
To prevent buccal malposition, the surgeon usually must initiate the osteotomy in the palatal bone of the extraction socket in the anterior maxilla. This is facili tated by using a sharp implant drill to create a purchase point for ideal positioning of the initial twist drill. A Lindemann side‐cutting drill can also be used (Al‐ Faraje, 2011, p. 13).
If the patient has thin bone or thin soft tissue, a bone and/or connective tissue graft can be placed at the implant surgery appointment to thicken the tissue. The crescent‐shaped soft tissue graft has been described for flapless cases (Han and Jeong, 2009). It must be reem phasized that bone and/or soft tissue grafting cannot make up for buccal malpositioning of the implant.
Treatment
If an implant cannot be stabilized in an ideal position, the implant should not be placed, and the extraction socket and osteotomy should be filled with a ridge preservation bone graft to minimize alveolar resorption while the extraction socket heals, a process that takes 3–6 months. Alternatively, a delayed approach has been shown to be predictable and successful (Buser et al., 2013).
If the implant is restored and midfacial recession has occurred, the clinician must evaluate the etiology of the recession and determine if reshaping of the restorative abutment or crown can reverse the recession. If an implant is poorly positioned, it must be removed.
Generally speaking, treatment of mucogingival defects around implants by soft tissue grafting is not pre dictable (Levine, Huynh‐Ba, and Cochran, 2014), and it cannot overcome poor implant positioning.
Sinus floor bone graft complications
The edentulous posterior maxilla often has limited vertical bone height for dental implant placement. Sinus floor bone grafts, commonly referred to as sinus lifts, are predictable methods of increasing the vertical bone height for implant placement by raising the floor of the maxillary sinus and filling the space with a bone graft.
The maxillary sinus is a pyramid‐shaped air space in the maxilla, above the roots of the maxillary posterior teeth, approximately 10–15 ml in volume. It is lined by the Schneiderian membrane, a pseudostratified ciliated columnar epithelium overlying a thin layer of connective tissue, between 0.45 and 1.40 mm thick (Katsuyama and Jensen, 2011, p. 14). The ostium drains the maxil lary sinus high on the medial wall.
There are two approaches to accessing the sinus floor for bone grafting: through the lateral wall of the maxillary sinus and crestally through an implant osteotomy.
These procedures are advanced surgical procedures and should only be attempted by experienced surgeons with proper training. The reader is guided through the presentation, prevention, and management of the most common sinus floor bone graft complications. The sur geon can use this chapter as a guide to manage sinus lift complications that arise in the office.
Lateral approach for sinus floor bone graft
The lateral approach involves preparing an opening in the lateral bony wall of the maxillary sinus to allow access to elevate the Schneiderian membrane off of the bony floor. A bone graft is placed between the mem brane and the bone, a membrane is placed over the window, and the site is closed. If sufficient height of native bone is available to stabilize an implant, an implant may be placed simultaneously. The lateral approach is appropriate for large bone grafts, for significant increase in vertical height, and for visual access of the sinus (Figure 7.15).
The lateral approach sinus lift is a predictable way to increase the vertical bone height for implant placement in the posterior maxilla. Implants placed into bone‐ grafted sinuses have high predictability and well‐ documented long‐term survival rates of greater than 95% (Del Fabbro, Wallace, and Testori, 2013; Wallace and Froum, 2003; Aghaloo and Moy, 2007). The following are among the more common complications of the lat eral approach to sinus floor bone grafting.
Membrane perforation
The most common intraoperative complication of the lateral approach is perforation of the Schneiderian mem brane, with an incidence of approximately 10% (range 4.8–56%) (Chiapasco, Casentini, and Zaniboni, 2009). Wallace (2010) estimated that experienced surgeons have about 25% perforation rate with rotary instrumen tation. If unrepaired, perforation can lead to loss of graft material, graft infection, reduced bone formation, and decrease in implant survival (Proussaefs et al., 2004).
Perforation of the sinus membrane can occur during preparation of the lateral window, during elevation of the membrane with hand instruments, during placement and condensation of graft material, or even on flap elevation with thin or absent bone (Wallace, 2010). Thin Schneiderian membranes are more prone to perforation, and complex sinus anatomy, such as bony septa, are associated with membrane perforation (Wallace, 2010, pp. 286–287).
Prevention
Proper presurgical evaluation of the bony sinus anatomy through three‐dimensional radiography, such as cone‐ beam scans, can assist the surgeon in planning the surgery (Figure 7.16). Preparation of the lateral window using a piezosurgery device that cuts bone but not soft tissue has been shown to reduce the perforation rate to as low as 7% (Wallace et al., 2007). If rotary instrumentation is to be used, a diamond bur would be preferable to a carbide bur (Wallace, 2010). Preparation of a large enough window to allow access to the sinus and around septa can prevent perforations (Wallace, 2010, p. 287). Wallace (2010) rec ommends a window that is 3 mm above the floor of the sinus, 3 mm distal to the anterior border of the sinus, and 15 mm in height. When elevating the membrane, it is important that the elevating instruments stay in contact with the bone. Piezosurgery devices can remove septa without tearing the thin overlying membrane.
Management
Small perforations can be repaired with a collagen membrane. If a perforation is small enough, it can close spontaneously. If the perforation occurs before full elevation of the membrane, the elevation should be carefully completed without expansion of the perfora tion. Larger perforation repairs can be attempted using resorbable sutures, although this is difficult. Membrane stabilization and graft containment are required for repairs. Techniques have been reported for managing large perforations (Testori et al., 2008). If containment and stability of the graft cannot be achieved, the procedure should be aborted, and the patient allowed to heal for 2–4 months before a subsequent attempt. This is an uncommon complication, occurring less than 1% of the time (Chiapasco, Casentini, and Zaniboni, 2009).
Intraoperative bleeding
The blood supply to the lateral maxillary sinus is provided by intraosseous and extraosseous branches of the maxillary artery, specifically the posterior superior alveolar artery, the greater palatine artery, and the infraorbital artery (Solar et al., 1999). Preparation of the lateral window results in bleeding from the lateral wall of the sinus. This bleeding is usually minor and of relatively short duration but at times can be profuse and difficult to control (Wallace, 2010, p. 284).
Prevention
Preoperative medical history evaluation should be done to determine if the patient is on anticoagulants or has a clot ting disorder. Cone‐beam scans can identify intraosseous vessels in the lateral wall, allowing for presurgical planning of window placement and surgical technique (Figure 7.17). Elian et al. (2005) showed that 53% of sinuses have a radiographically visible intraosseous vessel by CT scan, and that 20% of these cases have the vessel in a position where it is likely to be cut or damaged by preparation of the lateral wall. Piezosurgery can reduce the incidence and severity of intraoperative bleeding by reducing soft tissue damage. With this knowledge, the surgeon can preopera tively plan window placement and surgical technique to reduce the likelihood of blood vessel damage.
Management
Bleeding during lateral window preparation and mem brane elevation is flowy in nature and usually manageable (Wallace, 2010, p. 243). Use of a piezosurgery device will provide lavage with sterile saline, allowing better visualiza tion. If bleeding is more severe, other measures may be needed, such as direct pressure on the bleeding site, use of local vasoconstrictors, bone wax, or crushing of bone sur rounding an intraosseous vessel (Wallace, 2010).
Postoperative infection
Infection following lateral window sinus lifts has been reported to occur between 2 and 5.6% of cases (Testori et al., 2012). Most infections occur in the early postoper ative period, but some infections can show up after sev eral months.
Prevention
Testori et al. (2012) recommended preoperative antibi otics of amoxicillin 875 mg and clavulanic acid 125 mg twice per day, beginning 24 h before surgery and three times per day for 7 days postoperatively. Patients with a penicillin allergy are recommended to take clarithromy cin 250 mg twice per day and metronidazole 250 mg thrice per day, beginning 24 h before surgery and extending 7 days after surgery.
Infections can be reduced with aseptic surgical technique.
Evaluation and treatment for preoperative sinusitis, especially microbial in origin, can help prevent infec tions, especially if a perforation occurs.
Management
If a postoperative infection develops, it must be treated quickly with antibiotics. If unsuccessful, consider referral to an otolaryngologist and/or surgical debride ment of the infected tissues.
Postoperative sinusitis
Postoperative sinusitis has been reported following lat eral window sinus lifts, with reports of mild discom fort, stuffiness, and difficulty breathing through the nose (Wallace, 2010, p. 305). The average incidence of postoperative sinusitis has been reported to be 2.5%, with different studies reporting a range of 0–27% (Chiapasco, Casentini, and Zaniboni, 2009). Postoperative sinusitis is correlated with presurgical chronic sinusitis, membrane hypertrophy, and postextraction timing of the surgical procedure (Timmenga et al., 1997). More moderate to severe sinusitis following sinus lifts is most likely from blockage of the ostium, preventing proper drainage of the sinus (Wallace, 2010, p. 305). Sinusitis can be of inflammatory or infectious in nature and be caused by postoperative edema, bleeding from a sinus perforation, and exfoliation of graft particles into the sinus. Figure 7.18 shows a case of sinusitis caused by implants sticking through the Schneiderian membrane.
Prevention
Because many incidents of postoperative sinusitis are correlated with presurgical sinusitis, proper medical evaluation and assessment of the health of the sinus are important. If the patient has any sinus pathology, or if radiographs or three‐dimensional imaging show sinus pathology, it is prudent to refer for evaluation and treatment by an otolaryngologist. Antibiotics and/or anti‐inflammatory medication may be needed.
Proper surgical management is necessary to prevent postoperative sinusitis. If a perforation occurs, the repair must be stable and contain the graft.
Treatment
Decongestants and saline rinses can be performed to manage mild postoperative sinusitis. If the etiology is microbial, antibiotics may be needed. More severe cases of sinusitis should be referred to an otolaryngologist.
Osteotome/crestal approach sinus lift complications
The crestal approach, first described by Tatum (1986) and later modified by Summers (1994), involves prep aration of the implant osteotomy to within 1 mm of the sinus floor, then elevating the bone and soft tissue by fracturing the floor of the maxillary sinus and ele vating the Schneiderian membrane. An implant is placed simultaneously. Later techniques included addition of bone graft into the osteotomy and using the graft to elevate the membrane with osteotomes (Figure 7.19). More recent variations employ different methods of reaching the sinus floor and lifting the Schneiderian membrane.
The crestal approach is less invasive than the lateral approach, but it does not allow for visualization of the membrane and can achieve only limited increases in bone height. Fugazzotto (2005) reports that the maximum amount of predictable bone height with a crestal approach sinus lift is 2x – 2 mm, where x is the preoperative bone height. Several authors suggest a minimum of 5 mm bone height to be able to stabilize an implant placed simultaneously (Rosen, 2010; Summers, 1994).
The primary disadvantage of this technique is that it is not possible to visualize perforation of the Schneiderian membrane.
It has been recommended that the crestal approach sinus lift only be attempted by surgeons properly trained in performing a lateral window sinus lift (Katsuyama and Jensen, 2011, p. 6).
Perforation
Perforation of the Schneiderian membrane is the most common intraoperative complication of the crestal approach sinus lift (Fugazzotto, Melnick, and Al‐ Sabbagh, 2015). A systematic review by Tan et al. (2008) showed a range of perforation of 0–21.4%, with a mean of 3.8%. Perforation can be caused by overzealous elevation of the membrane, extending the osteotomes beyond the sinus floor, or the presence of sinus anatomy such as septa.
Prevention
Prevention of perforation includes proper case selection with a minimum of 5 mm of crestal bone height, a flat sinus floor, following the 2x – 2 rule (Fugazzotto, 2005) to prevent overstretching of the sinus membrane, cone‐ beam scans to evaluate bony anatomy of the sinus, radio graphic verification of the osteotome 1 mm below the sinus floor, and gentle surgical technique and tapping
Management
After preparation of the osteotomy and sinus floor ele vation, a Valsalva maneuver can be performed. If air passes from the maxillary sinus through the osteotomy, a perforation is present and must be managed with either repair using tissue fibrin glue (Pjetursson et al., 2004), repair from opening a lateral window, or by allowing the site to heal for 4–6 months, and then attempting the procedure again.
Inadequate primary stability
With limited bone height and porous type 4 bone in the posterior maxilla, there is potential for compromised primary stability of implants. Implants with less primary stability are more likely to be lost (Rosen, 2010).
Prevention
Proper case selection, with adequate buccopalatal bone width and at least 5 mm of native vertical bone height, is necessary for implant stability. The use of a tapered implant or tulip‐shaped implant can improve primary stability of the implant. If the bone is porous, the oste otomy can be undersized to improve primary stability. Finally, a provisional restoration must not have any contact with the implant during the healing period.
Poor patient experience and vertigo
The most well‐documented technique for crestal approach sinus lifts involves tapping for the elevation of the sinus floor, and this is perceived by patients as a negative experience (Diserens et al., 2006). This mallet ing technique has also been associated with benign par oxysmal positional vertigo (BPPV), with symptoms of dizziness, imbalance, lightheadedness, and nausea. BPPV is not progressive and symptoms subside or disap pear within 6 months (Rosen, 2010, p. 316).
Prevention
Prevention of the poor patient experience includes patient education (Rosen, 2010, p. 319), conscious sedation (Fugazzotto, Melnick, and Al‐Sabbagh, 2015), and surgical planning to minimize tapping, including drilling to within 1 mm of the sinus floor, and prepara tion of the osteotomy with drills rather than osteotomes. Fugazzotto, Melnick, and Al‐Sabbagh (2015) also rec ommend a gentle, intermittent malleting technique. Recent techniques and products can reduce or eliminate the need to fracture the sinus floor, with either special drills or piezosurgery devices that do not cut soft tissue.
Management
Management of BPPV should include referral to an oto laryngologist for evaluation. Management by the otolar yngologist may include an Epley maneuver.
Infection
Infection following a crestal approach sinus lift is uncommon but has been reported to occur between 0 and 2.5% of cases, with a mean of 0.8% (Tan et al., 2008). The most likely cause of infection is either poor oral hygiene, contamination of the implant or graft dur ing insertion, or infection from a perforated Schneiderian membrane, especially one with untreated sinusitis (Rosen, 2010, p. 311). Prevention includes resolution of preexisting sinus disease, aseptic surgical technique, and preoperative and postoperative antibiotics as described by Testori et al. (2012). Management of a postoperative infection includes systemic antibiotics.
While immediate implants have a high survival rate, several studies show higher failure rates compared to more delayed implant placement protocols. A meta‐ analysis of seven randomized controlled trials com paring immediate implants with immediate‐delayed implants and delayed implants did not show statisti cally significant differences of implant survival bet ween the groups, but several preliminary conclusions were made that were not statistically significant, including a possibly higher implant failure rate in the immediate group (Esposito et al., 2010). Individual randomized controlled trials either show no difference in implant survival (Siegenthaler et al., 2007) or a higher failure rate with immediate implants (Schropp et al., 2005; Lindeboom, Tjiook, and Kroon, 2006), with implant survival rates of as little as 91% in these studies. A cross‐sectional analysis also identified immediate implant placement as a risk factor for implant failure (Daubert et al., 2015).
Prevention
Although survival of the immediate implant is high, several studies show higher failure rates of immediate implants. Therefore, prevention of this complication encourages the use of a nonimmediate implant placement protocol.
The following list of requirements for success has been published for the prevention of complications with immediately placed implants (Wagenberg and Froum, 2010): (i) removal of all infectious material from the socket, (ii) adequate available bone and soft tissue, (iii) initial implant stability, (iv) patient cooperation with postsurgical maintenance, (v) apical or lateral stabiliza tion, (vi) residual infection removed, (vii) careful deter mination of patient expectations, and (viii) consideration of final outcome after healing.
Midfacial gingival recession in the anterior maxilla
A systematic review by Chen and Buser (2014) showed that esthetic outcomes are achievable with immediate implants in the anterior maxilla, but the esthetic results are more variable, and there is a higher frequency of midfacial recession than implants placed in a delayed fashion. A literature review showed 0.5–0.9 mm of midfacial gingival recession with immediate implant placement (Chen and Buser, 2009).
Risk factors
The two major risk factors identified in midfacial reces sion are buccal implant positioning and thin periodontal biotype (Chen et al., 2009). Buccal malposition of the immediate implant is a possibility because the extrac tion socket, which is more buccal than the ideal placement of the implant, tends to push the osteotomy and the implant into the empty socket.
Proper diagnosis and treatment planning can prevent poor esthetic outcome. The following factors are impor tant to consider: medical status, smoking habit, patient’s esthetic expectations, lip line, tissue biotype, shape of tooth crowns, infection at implant site, bone level of adjacent teeth, restorative status of neighboring teeth, width of edentulous span, soft tissue anatomy, and bone anatomy of alveolar crest.
Prevention
Ideal implant position in the anterior maxilla is palatal to the incisal edge, which will result in thicker hard and soft tissue buccal to the implant (Figure 7.14) and a slight buccal cantilever to the restoration.
Prevention first involves presurgical treatment planning with a three‐dimensional imaging that shows the volume and position of the bone. The clinician must decide before extraction whether an immediate implant can be stabilized in an ideal position. Ideally, an immediate implant in the anterior maxilla will have 5 mm of bone apical to the extraction socket to stabilize the implant.
If an implant can safely be placed into an extraction socket, the use of a tapered implant can allow for easier angulation of the implant for proper palatal emergence of the head of the implant. The narrower apex of the tapered implant reduces the incidence and severity of fenestration of the bony concavity of the anterior max illa during the osteotomy, and it increases the primary stability of the implant.
To prevent buccal malposition, the surgeon usually must initiate the osteotomy in the palatal bone of the extraction socket in the anterior maxilla. This is facili tated by using a sharp implant drill to create a purchase point for ideal positioning of the initial twist drill. A Lindemann side‐cutting drill can also be used (Al‐ Faraje, 2011, p. 13).
If the patient has thin bone or thin soft tissue, a bone and/or connective tissue graft can be placed at the implant surgery appointment to thicken the tissue. The crescent‐shaped soft tissue graft has been described for flapless cases (Han and Jeong, 2009). It must be reem phasized that bone and/or soft tissue grafting cannot make up for buccal malpositioning of the implant.
Treatment
If an implant cannot be stabilized in an ideal position, the implant should not be placed, and the extraction socket and osteotomy should be filled with a ridge preservation bone graft to minimize alveolar resorption while the extraction socket heals, a process that takes 3–6 months. Alternatively, a delayed approach has been shown to be predictable and successful (Buser et al., 2013).
If the implant is restored and midfacial recession has occurred, the clinician must evaluate the etiology of the recession and determine if reshaping of the restorative abutment or crown can reverse the recession. If an implant is poorly positioned, it must be removed.
Generally speaking, treatment of mucogingival defects around implants by soft tissue grafting is not pre dictable (Levine, Huynh‐Ba, and Cochran, 2014), and it cannot overcome poor implant positioning.
Sinus floor bone graft complications
The edentulous posterior maxilla often has limited vertical bone height for dental implant placement. Sinus floor bone grafts, commonly referred to as sinus lifts, are predictable methods of increasing the vertical bone height for implant placement by raising the floor of the maxillary sinus and filling the space with a bone graft.
The maxillary sinus is a pyramid‐shaped air space in the maxilla, above the roots of the maxillary posterior teeth, approximately 10–15 ml in volume. It is lined by the Schneiderian membrane, a pseudostratified ciliated columnar epithelium overlying a thin layer of connective tissue, between 0.45 and 1.40 mm thick (Katsuyama and Jensen, 2011, p. 14). The ostium drains the maxil lary sinus high on the medial wall.
There are two approaches to accessing the sinus floor for bone grafting: through the lateral wall of the maxillary sinus and crestally through an implant osteotomy.
These procedures are advanced surgical procedures and should only be attempted by experienced surgeons with proper training. The reader is guided through the presentation, prevention, and management of the most common sinus floor bone graft complications. The sur geon can use this chapter as a guide to manage sinus lift complications that arise in the office.
Lateral approach for sinus floor bone graft
The lateral approach involves preparing an opening in the lateral bony wall of the maxillary sinus to allow access to elevate the Schneiderian membrane off of the bony floor. A bone graft is placed between the mem brane and the bone, a membrane is placed over the window, and the site is closed. If sufficient height of native bone is available to stabilize an implant, an implant may be placed simultaneously. The lateral approach is appropriate for large bone grafts, for significant increase in vertical height, and for visual access of the sinus (Figure 7.15).
The lateral approach sinus lift is a predictable way to increase the vertical bone height for implant placement in the posterior maxilla. Implants placed into bone‐ grafted sinuses have high predictability and well‐ documented long‐term survival rates of greater than 95% (Del Fabbro, Wallace, and Testori, 2013; Wallace and Froum, 2003; Aghaloo and Moy, 2007). The following are among the more common complications of the lat eral approach to sinus floor bone grafting.
Membrane perforation
The most common intraoperative complication of the lateral approach is perforation of the Schneiderian mem brane, with an incidence of approximately 10% (range 4.8–56%) (Chiapasco, Casentini, and Zaniboni, 2009). Wallace (2010) estimated that experienced surgeons have about 25% perforation rate with rotary instrumen tation. If unrepaired, perforation can lead to loss of graft material, graft infection, reduced bone formation, and decrease in implant survival (Proussaefs et al., 2004).
Perforation of the sinus membrane can occur during preparation of the lateral window, during elevation of the membrane with hand instruments, during placement and condensation of graft material, or even on flap elevation with thin or absent bone (Wallace, 2010). Thin Schneiderian membranes are more prone to perforation, and complex sinus anatomy, such as bony septa, are associated with membrane perforation (Wallace, 2010, pp. 286–287).
Prevention
Proper presurgical evaluation of the bony sinus anatomy through three‐dimensional radiography, such as cone‐ beam scans, can assist the surgeon in planning the surgery (Figure 7.16). Preparation of the lateral window using a piezosurgery device that cuts bone but not soft tissue has been shown to reduce the perforation rate to as low as 7% (Wallace et al., 2007). If rotary instrumentation is to be used, a diamond bur would be preferable to a carbide bur (Wallace, 2010). Preparation of a large enough window to allow access to the sinus and around septa can prevent perforations (Wallace, 2010, p. 287). Wallace (2010) rec ommends a window that is 3 mm above the floor of the sinus, 3 mm distal to the anterior border of the sinus, and 15 mm in height. When elevating the membrane, it is important that the elevating instruments stay in contact with the bone. Piezosurgery devices can remove septa without tearing the thin overlying membrane.
Management
Small perforations can be repaired with a collagen membrane. If a perforation is small enough, it can close spontaneously. If the perforation occurs before full elevation of the membrane, the elevation should be carefully completed without expansion of the perfora tion. Larger perforation repairs can be attempted using resorbable sutures, although this is difficult. Membrane stabilization and graft containment are required for repairs. Techniques have been reported for managing large perforations (Testori et al., 2008). If containment and stability of the graft cannot be achieved, the procedure should be aborted, and the patient allowed to heal for 2–4 months before a subsequent attempt. This is an uncommon complication, occurring less than 1% of the time (Chiapasco, Casentini, and Zaniboni, 2009).
Intraoperative bleeding
The blood supply to the lateral maxillary sinus is provided by intraosseous and extraosseous branches of the maxillary artery, specifically the posterior superior alveolar artery, the greater palatine artery, and the infraorbital artery (Solar et al., 1999). Preparation of the lateral window results in bleeding from the lateral wall of the sinus. This bleeding is usually minor and of relatively short duration but at times can be profuse and difficult to control (Wallace, 2010, p. 284).
Prevention
Preoperative medical history evaluation should be done to determine if the patient is on anticoagulants or has a clot ting disorder. Cone‐beam scans can identify intraosseous vessels in the lateral wall, allowing for presurgical planning of window placement and surgical technique (Figure 7.17). Elian et al. (2005) showed that 53% of sinuses have a radiographically visible intraosseous vessel by CT scan, and that 20% of these cases have the vessel in a position where it is likely to be cut or damaged by preparation of the lateral wall. Piezosurgery can reduce the incidence and severity of intraoperative bleeding by reducing soft tissue damage. With this knowledge, the surgeon can preopera tively plan window placement and surgical technique to reduce the likelihood of blood vessel damage.
Management
Bleeding during lateral window preparation and mem brane elevation is flowy in nature and usually manageable (Wallace, 2010, p. 243). Use of a piezosurgery device will provide lavage with sterile saline, allowing better visualiza tion. If bleeding is more severe, other measures may be needed, such as direct pressure on the bleeding site, use of local vasoconstrictors, bone wax, or crushing of bone sur rounding an intraosseous vessel (Wallace, 2010).
Postoperative infection
Infection following lateral window sinus lifts has been reported to occur between 2 and 5.6% of cases (Testori et al., 2012). Most infections occur in the early postoper ative period, but some infections can show up after sev eral months.
Prevention
Testori et al. (2012) recommended preoperative antibi otics of amoxicillin 875 mg and clavulanic acid 125 mg twice per day, beginning 24 h before surgery and three times per day for 7 days postoperatively. Patients with a penicillin allergy are recommended to take clarithromy cin 250 mg twice per day and metronidazole 250 mg thrice per day, beginning 24 h before surgery and extending 7 days after surgery.
Infections can be reduced with aseptic surgical technique.
Evaluation and treatment for preoperative sinusitis, especially microbial in origin, can help prevent infec tions, especially if a perforation occurs.
Management
If a postoperative infection develops, it must be treated quickly with antibiotics. If unsuccessful, consider referral to an otolaryngologist and/or surgical debride ment of the infected tissues.
Postoperative sinusitis
Postoperative sinusitis has been reported following lat eral window sinus lifts, with reports of mild discom fort, stuffiness, and difficulty breathing through the nose (Wallace, 2010, p. 305). The average incidence of postoperative sinusitis has been reported to be 2.5%, with different studies reporting a range of 0–27% (Chiapasco, Casentini, and Zaniboni, 2009). Postoperative sinusitis is correlated with presurgical chronic sinusitis, membrane hypertrophy, and postextraction timing of the surgical procedure (Timmenga et al., 1997). More moderate to severe sinusitis following sinus lifts is most likely from blockage of the ostium, preventing proper drainage of the sinus (Wallace, 2010, p. 305). Sinusitis can be of inflammatory or infectious in nature and be caused by postoperative edema, bleeding from a sinus perforation, and exfoliation of graft particles into the sinus. Figure 7.18 shows a case of sinusitis caused by implants sticking through the Schneiderian membrane.
Prevention
Because many incidents of postoperative sinusitis are correlated with presurgical sinusitis, proper medical evaluation and assessment of the health of the sinus are important. If the patient has any sinus pathology, or if radiographs or three‐dimensional imaging show sinus pathology, it is prudent to refer for evaluation and treatment by an otolaryngologist. Antibiotics and/or anti‐inflammatory medication may be needed.
Proper surgical management is necessary to prevent postoperative sinusitis. If a perforation occurs, the repair must be stable and contain the graft.
Treatment
Decongestants and saline rinses can be performed to manage mild postoperative sinusitis. If the etiology is microbial, antibiotics may be needed. More severe cases of sinusitis should be referred to an otolaryngologist.
Osteotome/crestal approach sinus lift complications
The crestal approach, first described by Tatum (1986) and later modified by Summers (1994), involves prep aration of the implant osteotomy to within 1 mm of the sinus floor, then elevating the bone and soft tissue by fracturing the floor of the maxillary sinus and ele vating the Schneiderian membrane. An implant is placed simultaneously. Later techniques included addition of bone graft into the osteotomy and using the graft to elevate the membrane with osteotomes (Figure 7.19). More recent variations employ different methods of reaching the sinus floor and lifting the Schneiderian membrane.
The crestal approach is less invasive than the lateral approach, but it does not allow for visualization of the membrane and can achieve only limited increases in bone height. Fugazzotto (2005) reports that the maximum amount of predictable bone height with a crestal approach sinus lift is 2x – 2 mm, where x is the preoperative bone height. Several authors suggest a minimum of 5 mm bone height to be able to stabilize an implant placed simultaneously (Rosen, 2010; Summers, 1994).
The primary disadvantage of this technique is that it is not possible to visualize perforation of the Schneiderian membrane.
It has been recommended that the crestal approach sinus lift only be attempted by surgeons properly trained in performing a lateral window sinus lift (Katsuyama and Jensen, 2011, p. 6).
Perforation
Perforation of the Schneiderian membrane is the most common intraoperative complication of the crestal approach sinus lift (Fugazzotto, Melnick, and Al‐ Sabbagh, 2015). A systematic review by Tan et al. (2008) showed a range of perforation of 0–21.4%, with a mean of 3.8%. Perforation can be caused by overzealous elevation of the membrane, extending the osteotomes beyond the sinus floor, or the presence of sinus anatomy such as septa.
Prevention
Prevention of perforation includes proper case selection with a minimum of 5 mm of crestal bone height, a flat sinus floor, following the 2x – 2 rule (Fugazzotto, 2005) to prevent overstretching of the sinus membrane, cone‐ beam scans to evaluate bony anatomy of the sinus, radio graphic verification of the osteotome 1 mm below the sinus floor, and gentle surgical technique and tapping
Management
After preparation of the osteotomy and sinus floor ele vation, a Valsalva maneuver can be performed. If air passes from the maxillary sinus through the osteotomy, a perforation is present and must be managed with either repair using tissue fibrin glue (Pjetursson et al., 2004), repair from opening a lateral window, or by allowing the site to heal for 4–6 months, and then attempting the procedure again.
Inadequate primary stability
With limited bone height and porous type 4 bone in the posterior maxilla, there is potential for compromised primary stability of implants. Implants with less primary stability are more likely to be lost (Rosen, 2010).
Prevention
Proper case selection, with adequate buccopalatal bone width and at least 5 mm of native vertical bone height, is necessary for implant stability. The use of a tapered implant or tulip‐shaped implant can improve primary stability of the implant. If the bone is porous, the oste otomy can be undersized to improve primary stability. Finally, a provisional restoration must not have any contact with the implant during the healing period.
Poor patient experience and vertigo
The most well‐documented technique for crestal approach sinus lifts involves tapping for the elevation of the sinus floor, and this is perceived by patients as a negative experience (Diserens et al., 2006). This mallet ing technique has also been associated with benign par oxysmal positional vertigo (BPPV), with symptoms of dizziness, imbalance, lightheadedness, and nausea. BPPV is not progressive and symptoms subside or disap pear within 6 months (Rosen, 2010, p. 316).
Prevention
Prevention of the poor patient experience includes patient education (Rosen, 2010, p. 319), conscious sedation (Fugazzotto, Melnick, and Al‐Sabbagh, 2015), and surgical planning to minimize tapping, including drilling to within 1 mm of the sinus floor, and prepara tion of the osteotomy with drills rather than osteotomes. Fugazzotto, Melnick, and Al‐Sabbagh (2015) also rec ommend a gentle, intermittent malleting technique. Recent techniques and products can reduce or eliminate the need to fracture the sinus floor, with either special drills or piezosurgery devices that do not cut soft tissue.
Management
Management of BPPV should include referral to an oto laryngologist for evaluation. Management by the otolar yngologist may include an Epley maneuver.
Infection
Infection following a crestal approach sinus lift is uncommon but has been reported to occur between 0 and 2.5% of cases, with a mean of 0.8% (Tan et al., 2008). The most likely cause of infection is either poor oral hygiene, contamination of the implant or graft dur ing insertion, or infection from a perforated Schneiderian membrane, especially one with untreated sinusitis (Rosen, 2010, p. 311). Prevention includes resolution of preexisting sinus disease, aseptic surgical technique, and preoperative and postoperative antibiotics as described by Testori et al. (2012). Management of a postoperative infection includes systemic antibiotics.
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