Inferior alveolar nerve repositioning in conjunction with placement of osseointegrated implants: A case report

Transcription

1 oral surgery oral medicine oral pathology wilh sections on endodontics and dental radiology Volume 63. Number 3. March 1987 oral surgery Editor: ROBERT B. SHIRA, D.D.S. School of Dental Medicine, Tufts University 1 Kneeland Street Boston, Massachusetts 021 I I Inferior alveolar nerve repositioning in conjunction with placement of osseointegrated implants: A case report Ole Jensen, D.D.S.. M.S..* and David Neck, D.D.S.,** Denver, Cola, A procedure for relocation of the inferior alveolar nerve to facilitate placement of endosseous implants is described. The technique permits placement of implants in an atrophied mandibular alveolar ridge that lacks sufficient vertical height superior to the mandibular canal. Placement of a fixed prosthesis instead of a removable appliance is facilitated. (ORAL SURC. ORAL MED. ORAL PATHOL 1987;63:263-8) A trophy of the alveolar ridge in the mandible is a common sequelae following the loss of the dentition and is especially evident in patients treated with an alveolar tissue-borne prosthesis. *2 Alveolar atrophy may progress to the point at which comfort, function, and esthetics are compromised.3*4 Several surgical techniques have been advocated for reconstruction of the denture-bearing area, including augmentation grafting with bone, cartilage, and hydroxylapatite; vestibuloplasty; and various osteotomy proceduress- O The success of these procedures is variable, and the final prosthetic restoration still requires an *In private practice, Denver, Cola. **General practice resident at University of Colorado, School of Dentistry. alveolar tissue-borne prosthesis that will place resorptive force on the reconstructed alveolar proces~. - ~ All of these procedures can adversely affect neurosensory function over the distribution of the peripheral nerves of the mandible, resulting in paresthesia that may be temporary or permanent.14*20-24 Many of these surgical procedures, such as the visor osteotomy or the various sandwich osteotomies, are primarily designed in order to avoid nerve injury but involve the internal architecture of the mandible and carry with them a greater risk of macrotrauma to the inferior alveolar nerve than do the only grafting procedures.l ~ Egbert and coworkers 8 advocated approaching the mandible from the inferior border in order to avoid injury of the nerves, by means of a sandwich bone-grafting osteotomy. They were able to avoid a sensory deficit in 16 of 19 patients with the 263

2 264 Jensen and Neck Oral Surg. March. I987 Fig. 1. Inferior alveolar nerve is positioned laterally following local decortication. use of this technique. Meanwhile, other authors report a greater incidence of nerve injury with similar operations carried out intraorally., I9 Simple repositioning procedures have also been used to lower the profile of the mental nerve and have been advocated in conjunction with vestibuloplasty procedures Permanent neurosensory disturbances to the mental nerve can result from these procedures, as well. Indeed, Alling28 reported a case in which the entire inferior alveolar nerve was repositioned laterally to the resorbed alveolar ridge as far distally as the region of the third molar. He found minimal paresthesia on one side after 30 months with sensation having returned to normal on the opposite side. Though an attempt is made in most surgical designs to avoid the nerve, some authors have suggested neurapraxia as a controlled therapeutic modality in selected vestibuloplasty procedures. Samit, in a series of more than 80 cases involving skin-graft vestibuloplasty procedures, intentionally produced paresthesia of the mental nerve by means of gentle traction to minimize postoperative discomfort. In all of the cases, complete sensory recovery occurred within 4 to 6 weeks. In general, mild nerve traction that is less than 5% of nerve length results in infrafascicular damage that is readily reversible in most instances.30~ 3 Repositioning of the mandibular nerve in relation to the placement of dental implants has not been widely discussed in the literature. Manipulation of the mental nerve has been employed in the placement of subperiosteal implants. 27* 32 No reported instances of repositioning of the inferior alveolar nerve to facilitate the placement of endosseous or osseointegrated implants were found in the literature. At present, osseointegrated implants are being proposed as an alternative that offers an improvement over other methods of preprosthetic surgery because of the morbidity associated with them its relatively low and a prosthetic reconstruction that is not alveolar tissue borne is obtainable.33 The European success rates for the fixed osseointegrated implant-supported prosthesis approach retention rates of fixed prosthetic appliances attached to the natural dentition, and is gaining general acceptance as a preferred preprosthetic modality.40 In general, recommended placement of the osseointegrated implant is confined, in the resorbed mandible, to the anterior region between the mental foramina.32s36-40 Placement of implants in the posterior region of the mandible requires an adequate amount of bone superior to the mandibular canal to permit osseointegration and to avoid trauma to the mandibular nerve.32* Placement of submersible endosseous implants in conjunction with surgical displacement of the inferior alveolar nerve in order to provide sufficient bone for an implant bed has not been reported. A case of a woman who underwent bilateral repositioning of the inferior alveolar neurovascular bundle to facilitate placement of osseointegrated implants is presented. CASE REPORT A 60-year-old woman had a chief complaint of an ill-fitting mandibular partial denture. The patient reported that she had worn a partial denture for 18 years. Clinical and radiographic evaluation revealed a greatly resorbed

3 Volume 63 Number 3 Inferior alveolar nerve repositioning 265 Fig. 2. Inferior alveolar nerve may be repositioned in a small localized area without repositioning of entire nerve. Fig. 3. After implant placement, nerve is permitted to lie passively against implant. mandibular alveolus (Class IV). The alveolar ridge clearly lacked sufficient height superior to the mandibular canal to permit routine placement of osseointegrated implants. The patient was presented with options, including ridge augmentation with vestibuloplasty. The patient related that she was dissatisfied with removable appliances in general and that she desired a fixed prosthesis. A treatment option was presented that involved lateral repositioning of the inferior alveolar nerve bilaterally followed by the immediate placement of osseointegrated implants. A fixed bridge would then be constructed 4 months after placement of the implant. The potential risks and benefits were explained. The patient chose to undergo placement of implants with lateral relocation of the inferior alveolar neurovascular bundle. Surgical technique The surgery was performed on an outpatient basis with the patient under intravenous sedation and local anesthesia. A small incision was made in the buccal mucosa at approximately the region of the left mandibular cuspid. This incision was enlarged through blunt and sharp dissection until the mental neurovascular bundle and the foramen were located and identified. The neurovascular bundle was retracted laterally with a suture looped around it. The incision extended outward to the buccal mucosa and was brought back posteriorly approximately 25 mm. The tissue and periosteum were reflected medially until the entire residual ridge distal to the mental foramen could be well visualized to the second molar area. With the area under copious irrigation, a slow-speed handpiece and a large,

4 266 Jensen and Neck Oral Surg. March, 1987 Fig. 4. A, Left side-inferior alveolar nerve repositioning. B, Right side-inferior alveolar nerve repositioning. Fig. 5. A, Preoperative radiograph. B, Postoperative radiograph.

5 Volume 63 Number 3 round bur were used to remove the mandibular cortica plate of bone lateral to the inferior alveolar canal. Thi removal continued until the contents of the mandibula canal could be directly visualized through a thin layer a bone. This remaining bone was then carefully dissectel away with a small curette, exposing the neurovascula bundle within the inferior alveolar canal. When sufficien access was obtained over a 15 mm length of the canal, th neurovascular bundle was gently dissected free from th canal by means of a looped suture for traction to aid in th blunt dissection. The blunt was then passively sutured t the periosteum with resorbable suture to maintain it lateral position (Figs. 1, 5A, 4A). A stone model, which had been prepared preoperative11 was measured to determine the correct placement of hydroxylapatite-coated endosseous implant (Calcitek, Inc San Diego, California). This implant was then place routinely. Because of the minimal thickness of the residue buccolingual ridge in the area adjacent to the implant, small amount of particulate hydroxylapatite was loose1 packed both medially and laterally over the ridge. Th surgical site was then irrigated and closed with resorbabl sutures. The same procedure, with minor variations, wa performed on the contralateral side, where a 10 mr portion of the nerve was lateralized without disturbing th exit point of the nerve at the mental foramen (Figs. 2, 51 4B). Placement of the patient s mandibular partial dentur was deferred for 4 weeks. Results The patient had complete subjective return of sensor function within 5 weeks after surgery. A fixed prosthesi was placed bilaterally 4 months after surgery (Fig. 3). DISCUSSION The biologic basis for peripheral nerve repositior ing has been established.2s-27~32 If the mandibula nerve is not excessively stretched or transected, it ha a greater likelihood of returning to sensory functior However, in most instances, a neurosensory defici will result from extensive manipulation of a peript era1 nerve.15 However, Samit has shown that, wit minimal manipulation, sensory function can retur consistently to preoperative levels. Furthermore, a long as continuity is maintained, a return to clinically normal state can be expected in the majoi ity of nerves displaced from their native sites.30s3 Th regenerative capacity of the peripheral nerve is gooc especially in the younger person. And, certainly, fre grafts have been shown to be successful in th treatment of traumatic anesthesia to the inferic alveolar nerve.4 However, the risk of permanent sensory deficitincluding anesthesia, hypesthesia, paresthesia, c hyperesthesia-is always present when a peripher; nerve is disturbed from its physiologic bed.)ov3 Eve Inferior alveolar nerve repositioning 267 minimally manipulated nerves may not return to function at 100% of their capacity. This could be due to disruption of the perineural vasculature or of the axonal tissues themselves or a combination of both processes. In any case, the decision to reposition a nerve so that prosthetic implant surgery can be done should not be taken lightly because of the potential risk of dysesthesia. SUMMARY A patient with bilateral free-end saddles in the mandible was treated with the use of fixed prostheses despite having severe alveolar atrophy that exposed the neurovascular bundle at the crest of the residual alveolus. Osseointegrated implants were placed in the first molars areas after lateral repositioning of the inferior alveolar nerves. Sensory function returned to normal bilaterally within 5 weeks. A fixed prosthesis was placed in function 4 months postoperatively without complication. REFERENCES 1. Atwood DA. Bone loss of edentulous alveolaridges. Eighth Annual James A. English Symposium on Oral Perspectives on Bone Biology, 1979, Buffalo, NY. J Periodontol 1979;50:1 l Thoma KH, Holland DJ. Atrophy of the mandible. ORAL SURG ORAL MED ORAL PATHOL 1951:4: Lekkas K, Wes BJ. Absolute augmentation of the extremely atrophic mandible. J Maxillofac Surg 1981;9: Lekkas K. Absolute augmentation of the mandible. Int J Oral Surg 1977;6: Baker RD, Terry BC, Davis WH, Cannole PW. Long-term results of alveolar ridge augmentation. J Oral Surg 1979; 37: Block MS, Kent JN. Long-term radiographic evaluation of hydroxylapatite-augmented mandibular alveolar ridges. J Oral Maxillofac Surg 1984;42: Boyne PJ, Cooksey DE. Use of cartilage and bone implants in restoration of edentulous ridges. J Am Dent Assoc 1965; 71: Chang CC, Matukas JM, Lemons JE. Histologic study of hydroxylapatite as an implant material for mandibular augmentation. J Oral Maxillofac Surg 1983;41: Fazili M, v Overvest-Eerdmans GR, Vernooy AM, et al. Follow-up investigation of reconstruction of the alveolar process in the atrophic mandible. Int J Oral Surg 1978;7: Jensen OT. Combined hydroxylapatite augmentation and lip-switch vestibuloplasty in the mandible. ORAL SURG ORAL MED ORAL PATHOL 1985;60: Stoelinga PJ, Tideman H, Berger JS, de Koomen HA. Interpositional bone graft augmentation of the atrophic mandible: a preliminary report. J Oral Surg 1978;36: Wolford LM, Epker BN. The use of freeze-dried bone as a biologic crib for ridge augmentation. ORAL SIJRG ORAL MED ORAL PATHOL 1977;43: Wang JW, Waite DE, Steinjauser E. Ridge augmentation: an evaluation and follow-up report. 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6 266 Jensen and Neck Oral Surg. March Walter JM Jr, Gregg JM. Analysis of postsurgical neurologic alteration in the trigeminal nerve. J Oral Surg 1979;37: Cogswell WW. Surgical problems involving the mandibular nerve. J Am Dent Assoc 1942;29: Egbert M, Stoelinga PJW, Blijdorp PS, dekoomen HA. The three-piece osteotomy and interpositional bone graft for augmentation of the atrophic mandible. J Oral Maxillofac Surg 1986;44: dekoomen HA, Stoelinga PJ, Tideman H, et al. Interposed bone graft augmentation of the atrophic mandible. J Maxillofat Surg 1979;7: Merrill RG. Decompression for inferior alveolar nerve injury. J Oral Surg 1964;22: Merrill RG. Further studies in decomuression for inferior alveolar nerve injury. J Oral Surg 1966;24: Simpson HE. Injuries to the inferior dental and mental nerves. J Oral Surg 1958;16: Choukas NC, Toto PD, Nolan RF. A histologic study of the regeneration of the inferior alveolar nerve. J Oral Surg 1974;32: Frank VH. Paresthesia: evaluation of 16 cases. J Oral Surg 1959;17: Cooley D. A method for deepening the mandibular and maxillary sulci to correct deficient edentulous ridges. J Oral Surg 1952;10: Kruger GO: Textbook of oral and maxillofacial surgery. 5th ed. St. Louis: The CV Mosby Co, 1979: Laskin DM. Oral and maxillofacial surgery. Vol 2. St. Louis: The CV Mosby Co, 1985: Ailing C. Lateral repositioning of the inferior alveolar neurovascular bundle. J Oral Surg 1977;35: Samit A, Popowich LP. Mandibular vestibuloplasty: a clinical update. ORAL SURG ORAL MED ORAL PATHOL 1982;54: Gorio A, Millesi H, Mingringo H, eds. Posttraumatic peripheral nerve regeneration. New York: Raven Press, 1981; Seddon Sir H. Surgical disorders of the peripheral nerves. 2nd ed. Edinburgh: Churchill Livingstone, 1975: Babbush CA. Surgical atlas of dental implant techniques. Philadelphia: WB Saunders Co, 1980: Breine U, Branemark PI. Reconstruction of alveolar jaw bone. Stand J Plast Reconstr Surg 1980;14: Manski RJ. A synopsis of recent literature concerning the dental implant. J Oral Implant ;10: Schlegel KD. Follow-up findings in oral implants. J Oral Implant ;11: Branemark PI. osseointegration and its experimental background. J Prosthet Dent 1983;50: Kirsch A. The two-phase implantation method using IMZ intramobile cylinder implants. J Oral Implant ;l I: Lekholm U. Clinical procedures for treatment with osseointegrated dental implants. J Prosthet Dent 1983;50: Niznick GA. The core-vent implant system. J Oral Implant ;10: Adell R, Lekholm U, Rockier B, et al: A 15-year study of osseointegrated implants in the treatment of the edentulous jaw. Int J Oral Surg 1981;10: Noma H, Kakizawa T, Yamane G, Sasaki K. Repair of the mandibular nerve by autogenous grafting after partial resection of the mandible. J Oral Maxillofac Surg 1986;44:31-6. Reprint requests to. Dr. Ole Jensen 1633 Fillmore #5 Denver, CO 80206