RU2841926C1 - Method for isolating the damaged nerve region in a mandibular bone defect - Google Patents

Abstract

FIELD: medical science.

SUBSTANCE: invention relates to medicine, specifically to dentistry, and is intended for use in the prevention of neuropathy when extracting impacted third molars with a tight fit of the lower alveolar nerve. Surgical area is anaesthetised. After the mucosa and periosteum are incised with a drill, an access window is formed with preserving the tongue and buccal walls of the alveolar portion. Thereafter, the bone wound is cleaned with a curette spoon with bypassing the exposed region of the neurovascular bundle of the mandibular canal. Further, the wound is treated with normal saline, and an area of the exposed portion of the inferior alveolar nerve is visually determined. Oval coating is cut out of a sheet of the sterile haemostatic collagen sponge, adapted to the defect edges, the width of which exceeds the diameter of the bone defect by 8-10 mm, and laid on the bottom of the bone defect without pressure. In 2-5 minutes, an iodoform bandage is loosely laid on the sponge to fill the residual defect. Wound is sutured from above with closing sutures with leaving a wound canal to change the dressing. Dressing is performed on 2-3 postoperative day and every 7 days thereafter until the defect is healed by secondary tension.

EFFECT: by isolating the open segment of the inferior alveolar nerve in the bone cavity from external traumatic factors, the method enables reducing a rate of developing neuropathy, reduces the length of paresthesia of teeth and lower lip.

1 cl, 4 dwg, 2 ex

Description

The invention relates to medicine, namely to dentistry, and can be used to prevent neuropathy during the removal of impacted third molars with close adjacency of the lower alveolar nerve, as well as during cystectomy of volumetric cavity formations of the lower jaw.

Inferior alveolar nerve injury is a common complication of cystectomy and removal of impacted third molars of the lower jaw. Subsequent neuropathy, occurring in the form of paresthesia of the teeth and soft tissues of the face, causes significant discomfort to the patient and affects the quality of life. Improving the technique of surgical treatment and, in particular, the isolation of the nerve fiber from external traumatic factors is of scientific interest. Exposure in the bone cavity of the cyst of a section of the nerve located without the bone wall of the mandibular canal may be due to pathological growth and spread of the tumor, or anatomically close location of the roots of the third molar to it. In this case, the risk of injury to the inferior alveolar nerve during surgery increases many times: when separating the cyst membrane from the bone walls, dislocating the root of the tooth with an elevator, osteoectomy. In the postoperative period, the causes of nerve injury after the above operations may include: compression of the nerve by swelling, toxic effects of the iodoform bandage, and development of infection in the socket of the extracted tooth.

A method for isolating the damaged nerve area with a polytetrafluoroethylene tube is known (Patent No. RU 2446757 C1), in which the proximal end of the damaged peripheral nerve is inserted into a tubular implant made of polytetrafluoroethylene. An epineural suture of the damaged nerve is made, and the tubular implant is shifted in the distal direction until the suture area of the damaged nerve is completely covered. The method allows to reduce postoperative complications, namely the formation of neuromas and compression of the nerve by scar tissue. Of course, this method allows to qualitatively isolate the damaged area of the nerve along the entire length of the wound. However, the method is used only in cases of complete dissection of the nerve, and to insert the tube, mobilization of the ends of the nerve is required, which is impossible to do in a bone defect of the lower jaw.

There is an experimental method of isolating a damaged peripheral nerve from adjacent tissues with carboxymethylcellulose (Patent No. RU 2379040 C1). For this purpose, 2 ml of a hydrogel of the polymer sodium salt of carboxymethylcellulose are injected into an experimental animal in the area of traumatic nerve injury during surgery. The invention allows for effective prevention due to the fact that the gel forms a "barrier" between the surface of the nerve and the surrounding tissues, preventing the growth of connective tissue and cicatricial compression of the nerve fiber, which, in turn, improves the regeneration of nerve tissue and promotes the restoration of nerve conductivity. This method may have certain prospects, but the effect of this drug on bone regeneration, as well as the creation of antibacterial properties of the material, remain not fully known.

A method of filling bone defects with alginate material to reduce the degree of bone tissue atrophy is known (Patent No. RU 2807879 C1). In this method, curettage of the socket of the extracted tooth is performed and the socket is expected to be completely filled with blood. The resulting defect is filled with alginate material "LitAr" with silver by 70% by volume. Then, the socket of the extracted tooth is sutured with non-absorbable suture material 5/0 with two Z-shaped sutures. After that, the sutures are filled with a flowable light-curing composite material, completely blocking the entrance to the alveolus. This method may be able to create a barrier between the inferior alveolar nerve and the external environment, but the displacement of the hardened material can provoke local pinching of the nerve, which can lead to neuropathy or neuritis.

There is a method for treating and preventing alveolitis of the jaw (Patent (No. RU 2391111 C1), based on the removal of fragments and areas of non-viable bone tissue from the socket of the extracted tooth, characterized in that the socket after tooth extraction is filled with a sterile collagen sponge soaked in bifidumbacterin prepared ex tempore. The disadvantage of this method is that it has limited indications and is suitable for cases of infected bone wounds. Also, careful curettage of all the walls of the socket using this method can lead to injury of the inferior alveolar nerve and the development of persistent neuropathy in the future.

The technical objective of the claimed invention is to develop a method for isolating an open section of the inferior alveolar nerve in the bone cavity from external traumatic factors.

The technical result of the claimed invention is the development of a method for isolating an open section of the inferior alveolar nerve in the bone cavity from external traumatic factors, eliminating the disadvantages of analogues, reducing the incidence of neuropathy, and shortening the duration of paresthesia of the teeth and lower lip.

The set task is achieved by curettage of the walls of the bone defect above the visible borders of the inferior alveolar nerve, rinsing the bone cavity with sterile saline, drying the wound with a sterile gauze pad, isolating the open area of the nerve from the bone cavity with a collagen hemostatic sponge slightly larger than the bone defect, loosely tamponing the residual cavity with an iodoform bandage to prevent wound infection, and applying converging sutures to the wound.

The method is carried out as follows. After anesthesia of the lower jaw and teeth on the side of the operation with a solution of Articaine hydrochloride with epinephrine 1:100000. An incision is made in the mucosa and periosteum above the pathological focus (Fig. 1). A drill is used to form an access window with the most gentle osteoectomy while preserving the lingual and buccal walls of the alveolar part. The bone wound is cleaned of bone chips, fragments of tooth tissue with a curettage spoon, while the area of the open section of the vascular-nerve bundle of the mandibular canal is bypassed (Fig. 2). Then the wound is treated abundantly with saline. A periodontal probe is used to measure the area of the exposed section of the lower alveolar nerve, deprived of the cortical layer for anatomical reasons due to the close adhesion of the root of the third molar or pathological - due to the spread of the membrane of the cystic formation. An oval-shaped covering is cut out of a sheet of sterile hemostatic collagen sponge with scissors, adapting it to the edges of the defect, exceeding the diameter of the bone defect by 8-10 mm in width. A section of collagen sponge is placed on the bottom of the bone defect without pressure (Fig. 3). Then wait 2 to 5 minutes for the collagen sponge to adhere, after which an iodoform bandage is loosely placed on the sponge, filling the residual defect. Approximating sutures are applied to the wound from above, leaving a wound channel for changing the dressing (Fig. 4). Dressings are changed on the 2nd-3rd day after the operation and then every 7 days until the defect heals by secondary intention.

According to this method, 23 patients with epithelial formations of the jaws and 280 patients with impacted teeth were operated. In all cases, after tooth extraction or cystectomy, an open section of the vascular-nerve bundle of the mandibular canal of varying length was determined in bone defects. According to the above-described method, the nerve was isolated from the bone wound. It was found that the proposed method of nerve isolation leads to a decrease in the frequency of neuropathy. Also, the proposed method led to a reduction in the terms of paresthesia of the teeth and lower lip with damage to the inferior alveolar nerve of 1-2 degrees compared to the control group.

Example 1.

Patient V., 48 years old. Came with complaints of distending pain in the lower jaw, pain when opening the mouth. Objectively, the mouth opening is 2.5 cm. Palpation reveals local thickening of the lower jaw in the area of the body of the alveolar part and the angle on the left. According to CBCT data, a 4x2 cm cystic formation was detected, which displaces the mandibular canal, the bone wall of the canal in the area of the tumor is thinned and in places cannot be traced. Also, an impacted third molar is determined in the cyst cavity, which has a medial slope.

Diagnosis: Follicular cyst of the branch, alveolar part and body of the lower jaw. Retention of tooth 38. Tight fit of the mandibular canal. Procedure. Under infiltration and conduction anesthesia, Ultracaine DS forte 1.7 ml × 3. An oblique incision was made from the second molar, outward from the retromolar fossa with a transition to the anterior edge of the branch of the lower jaw. The bone was skeletonized with a raspatory, a wide trepanation window was made with a burr. Complete removal of the epithelial formation membrane and the retained tooth 38 was performed. Visual examination of the bottom of the cyst cavity revealed an open area of the vascular-nerve bundle of the mandibular canal. The cyst cavity was treated with saline. The open area of the nerve was covered with a collagen hemostatic sponge, 1.5 × 3 cm in size, which exceeds the bone defect by 8 mm. Five minutes after the sponge was filled with a blood clot and adhered to the walls of the bone cavity, a loose tamponade of the residual cavity was performed with an iodoform bandage. The wound was sutured to bring it together without interfering with subsequent dressings through the formed bone window. A postoperative dressing was performed the following day. The bottom of the bone cavity after removing the gauze bandage was covered with a blood clot over the entire area of the bottom of the defect. No signs of neuropathy of the inferior alveolar nerve were detected in the postoperative period; dressings were performed every 2 days for 7 days until the defect healed by secondary intention.

Example 2.

Patient A., aged 37. Came with complaints of pain in the area of an unerupted wisdom tooth. Objectively, the mouth opening is 3.5 cm. The mucous membrane of the retromolar fossa on the left is hyperemic, upon probing a deep mucous hood and the crown of the impacted tooth are determined. According to CBCT data, the mandibular canal is adjacent to tooth 38. The cortical layer of the canal at the level of the impacted 38 is not determined. The tooth has a distoangular position, there is no room in the dental arch for eruption. In the area of the impacted tooth, topical anesthesia with 10% Lidocaine, conduction mandibular and infiltration anesthesia with Sol. Articaini hydrochloridi 4% + Sol. Adrenalini 1:200,000 (Ultracain DS) - 1.7 ml + 0.8 ml were performed. An incision was made in the retromolar fossa, the alveolar part was skeletonized. An osteoectomy was performed with a drill, the crown and root part of tooth 38 were released above the mandibular canal. The tooth was fragmented with a drill. The impacted tooth was removed using a drill and elevators. An open section of the vascular-nerve bundle of the mandibular canal was visually determined in the socket of the extracted tooth, with no signs of damage to its integrity. An oval-shaped covering with a diameter of 20 mm, exceeding the diameter of the bone defect by 10 mm, was cut out from a sheet of collagen sponge, which was placed over the open section of the nerve, without pressure on it. After 2 minutes, the residual cavity was loosely filled from above with a wound dressing - iodoform bandage. The edges of the wound were brought together with interrupted sutures. The dressing was changed the day after the operation, no signs of neuropathy in the innervation zone of the inferior alveolar nerve were detected. When the iodoform bandage was replaced, the bottom of the bone defect was filled with a blood clot. Further wound healing occurred by secondary intention without complications, dressings were performed every 3 days for 7 days until the defect healed by secondary intention.

Claims (1)

A method for isolating the area of a damaged nerve in a bone defect of the lower jaw, which consists in anesthetizing the surgical area, making an incision of the mucosa and periosteum, and after cleaning the socket using a sterile collagen sponge, characterized in that after incision of the mucosa and periosteum with a drill, an access window is formed while preserving the lingual and buccal walls of the alveolar part, after which the bone wound is cleaned with a curettage spoon, bypassing the area of the open section of the vascular-nerve bundle of the mandibular canal, then the wound is treated with saline and the area of the exposed section of the lower alveolar nerve is visually determined, then an oval-shaped covering is cut out from a sheet of sterile hemostatic collagen sponge, adapting it to the edges of the defect, exceeding the diameter of the bone defect by 8-10 mm in width, and placed on the bottom of the bone defect without pressure, after 2-5 minutes a loose an iodoform bandage is applied, filling the residual defect, then converging sutures are applied to the wound from above, leaving a wound channel for changing the dressing, dressings are changed on the 2-3 day after the operation and then every 7 days until the defect heals by secondary intention.