MAXILLARY NERVE Philip M. Mahoneyt Regional analgesia enjoys widespread and frequent use throughout the various disciplines of medicine. Of all medical specialists, there are indeed few who utilize local or regional analgesia as effectively, as do the dentists. Within dentistry, the importance of mastering the several techniques of regional analgesia cannot be overemphasized. Texts describing the philosophy and science of dental analgesia stress certain injections of the trigeminal nerve which will allow the operator to practice painless dentistry. These include the PSA (posterior superior alveolar), infraorbital, greater palatine, nasopalatine, various submucosal infiltrations, and the inferior alveolar nerve block. Regional analgesia for restorative and surgical manipulation within the maxilla and maxillary teeth, may be achieved by a technique which causes much less physical and psychological trauma to the patient. This technique, the maxillary nerve (V2) block would replace the more common series of infiltrations and field blocks. A review of the literature shows both intraoral and extraoral approaches. Familiarity with these various techniques will determine the feasibility of this injection in the office of a general practitioner. A nagging question as to why this analgesic block is not taught in dental schools or utilized more frequently in practice should be posed. Applications and Advantages: The maxillary nerve block is useful for operations in three main areas: the mouth, the nose, and the medical part of the face. Block of the maxillary nerve provides anesthesia of the upper jaw and all its associated structures. Operations such as maxillary dental extractions, antrostomy, Caldwell-Luc operation, repair of maxillary fractures, excision of torus palatinus, and iSubmitted to ADSA Student Essay Contest. tSenior student, University of Pittsburgh, School of Dentistry.
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other procedures involving the hard and soft palate can be done with this method.' Differentiation between neuralgias and in relief of pain of maxillary nerve origin would be facilitated by this block as would extractions of abscessed teeth in those instances in which it is not desirable to inject into infected regions. Compared to infiltration anesthesia, maxillary nerve block provides a much broader scope for surgery. Patients accept this approach better than other techniques which require multiple injections; a case in point is extensive maxillary dental extraction which necessitates painful palatal injections in addition to multiple buccal and labial infiltrations. When combined with effective intravenous conscious sedation, maxillary nerve block elicits little reaction from the patient.2 Compared to general anesthesia, apart from obviating the dangers of this technique in poor risk patients, maxillary nerve block offers other advantages. First, bleeding is minimized. This effect is enhanced by use of a controlled quantity of epinephrine than is possible with certain inhalation anesthetics. Second, the absence of an oral-endotracheal tube eliminates competition for the same field between surgeon and anesthesiologist. Moreover, because the laryngeal reflexes are preserved, the airway is protected from blood, tissue fragments, and packs, both during the operation and in the early postoperative period. Third, with regional anesthesia, several of the procedures that have been discussed may be performed expeditiously and less expensively in the office rather than in the hospital.3 Technique: The maxillary nerve can be blocked after it exists the foramen rotundum as it enters the pterygopalatine fossa. Several techniques of approach to this nerve will be described: A. Intraoral route 1. Around tuberosity; High tuberosity technique4 47
2. Through the greater palatine foramen and canal5 B. Extraoral route 1. By way of the sigmoid notch of the mandible6 2. Anterior to the coronoid proces of the mandible7 The very multiplicity of techniques suggest that maxillary nerve block may be frequently unsuccessful or associated with complications. Indeed, elaborate anatomic measurements have been described to facilitate blockade of the nerve, these being deemed essential to insure success and to prevent complications; but the measurements of one author have not always led to reproducible results in the hands of another. Intraoral: Of the two approaches, the first to be discussed is made through the greater palatine foramen. The location varies anteroposteriorly from between the first and second molars to between the second and third molars. On occasion, it can be slightly anterior or posterior to these points. Clinical observations that facilitate finding the foramen have been evolved. Antero-posteriorly, the foramen is always in line with the hamular process of the pterygoid bone. Laterally the foramen is located at the junction of the horizontal plate of the palatine bone and the alveolar process. How far superiorly to insert the needle? Measurements evolved so accurately by Jorgensen8 have been relied on. They consist of measuring the distance from the infraorbital margin to the gingival margin of the maxillary second bicuspid on the same side that the injection is to be made. Three millimeters are subtracted and the remainder is used as the appropriate needle distance. The foramen is entered and the needle advanced to the preset marker (any resistance should not be overcome by force, but the needle should be withdrawn slightly and again advanced very slowly-if continued resistance is met, regardless of how slight, the attempt should be discontinued9 2 to 3 cc of anesthetic solution is injected after aspirating to avoid intravascular deposit. Maximum anesthesia is obtained in 5 to 15 minutes. The second intraoral approach is known 48
as the high tuberosity technique. With a retractor, or the forefinger of the left band placed at the angle of the mouth, the cheek is retracted upward and backward to permit exposure of the first molar tooth.10 The needle is inserted into the mucosal reflection above the first upper molar and is then advanced in a direction backward, upward, and inward, tangent to the tuberosity of the maxilla, so that it makes an angle of approximately 40 degrees with the sagittal plane of the head. The point of the needle loses contact with the bony surface at a distance of 3 to 4 cm. from its point of entry. It is then introduced 0.5 cm. further, and after aspirating, 2 cc. of anesthetic solution is slowly injected. Extraoral: There are basically two ways of approaching the maxillary nerve in the sphenomaxillary fossa by the lateral or zygomatic route: 1. The zygomatic arch is bisected and a wheal is raised just below this bisector. An 8 cm. 22 gauge needle which has been threaded with a rubber recorder is introduced through the wheal in a direction normal of the median plane of the head, and advanced deeply until it makes contact with the lateral plate of the pterygoid process. The bone is felt ordinarily when about half the length of the needle has disappeared into the tissues. The recorder is then set 1 cm. from the surface of the skin, the needle is then withdrawn until its point reaches the subcutaneous tissues, so that its direction may be changed, and it is then reintroduced and inclined slightly forward toward the sphenomaxillary fossa until the recorder reaches the surface of the skin. If no bony contact is now obtained, the point of the needle is in the sphenomaxillary fossa. The aspiration test is performed, and if negative, 2 cc. of anesthetic solution is injected."l 2. A 4 cm. 24 gauge needle is introduced into the angle formed by the anterior border of the coronoid process of the ascending ramus of the mandible with the lower margin of the zygoma.'2 The needle is introduced transversely and directed slightly upward toward the tuberosity of the maxilla. After making contact with the bone, it is withdrawn, sufficiently so that its direction may be changed and it may
ANEsTHEsiA PROGRESS
be reintroduced inclined backward to a slight degree until it is felt entering the sphenomaxillary fossa, immediately after losing contact with the maxilla. The needle is then at a depth of approximately 5 or 6 cm. from the skin surface. The general direction of the needle is then upward, backward, and toward the apex of the orbit. After making the aspiration test, 2 cc. of anesthetic solution is then injected. Hematomas of the cheek are not infrequent when performing this block. Complications: Apart from those complications which are common to all types of nerve blocks, specific complications of maxillary nerve block include exophthalmos, edema of the eyelids, anesthesia of the ophthalmic nerve and paralysis of the abducens nerve-all of which obviously are undesirable, but most likely due to the injection of excessive volumes of solutions too high into the sphenomaxillary fossa. Other complications include the accidental penetration of the orbit and intraorbital injection, intracranial injection, and deposition of anesthetic solution into subarachnoid space with consequent unconsciousness.13 Of all the possible complications of maxillary nerve block, the most important one is the failure to recognize apnea, which is induced by subarachnoid injection, and consequent failure to institute assisted respiration until spontaneous respiration returns. As meningitis also is a potential sequel to intracranial penetration, antibiotics should be given in such cases. Conclusion: The maxillary nerve block has been investigated with regard to the possibility of its utilization in the office of the general practitioner, and feasibility of its routine use within the environment of a dental school. The most popular techniques for obtaining this block have been described briefly. The application of this injection may be advantageous to the dental patient in terms of reduced psychological trauma when used in conjunction with adequate intravenous conscious sedation. Although the possibility exists for the routine use of the V2 block in the office of the general practitioner, it appears the technique can be most useful to practitionMARCH-APRIL, 1977
ers of oral surgery, either in the hospital or office setting, especially if combined with intravenous conscious sedation. It has proved effective, dependable, and safe in some 4,900 cases.1415, However, because of the possibility of rare but potentially serious complications, maxillary nerve block should be performed only in situations where personnel experienced in resuscitative measures, and necessary equipment are available. BIBLIOGRAPHY 1. Poore T E Maxillary nerve block-a useful technique J Oral Surg Oct 1973. 2. Ibid Poore p 750 3. Ibid Poore p 750 4. Adriani J Labat's Regional Anesthesia, its technique and clinical application Phila W B Saunders Co 1976 5. Stebbins H N and Burch R J Intraoral and extraoral injections J Oral Surg Jan 1961 6. Ibid Adriani p 92 7. Ibid Adriani p 94 8. Ibid Stebbins p 23 (see below) 9. Monheim L M Local anesthesia and pain control in dental practice, C V Mosby Co 1969 10. Ibid Adriani p. 96 11. Ibid Adriani p 92 12. Ibid Adriani p 94 13. Ibid Poore p 754 14. Ibid Poore p 749 2,900 Maxillary nerve blocks performed over 10 year period at Mayo Clinic. 15. Ibid Stebbins p 22, Over 2,000 cases of Maxillary nerve block over 5 year period at Lackland Air Force Base Texas. 8. Jorgensen N B Measurements for intraoral block of the maxillary nerve. J. Oral Surg Jan 1948
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ANNOUNCEMENT Stanley R. Spiro, D.D.S., of Hempstead, N.Y., has been appointed as consultant/ expert in dental anesthesiology to the: Division of Surgical-Dental Drug Products of the Bureau of Drugs, Food and Drug Administration Department of Health, Education, and
Welfare, Rockville, Maryland 49
MARCH-APRIL, 1977
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other procedures involving the hard and soft palate can be done with this method.' Differentiation between neuralgias and in relief of pain of maxillary nerve origin would be facilitated by this block as would extractions of abscessed teeth in those instances in which it is not desirable to inject into infected regions. Compared to infiltration anesthesia, maxillary nerve block provides a much broader scope for surgery. Patients accept this approach better than other techniques which require multiple injections; a case in point is extensive maxillary dental extraction which necessitates painful palatal injections in addition to multiple buccal and labial infiltrations. When combined with effective intravenous conscious sedation, maxillary nerve block elicits little reaction from the patient.2 Compared to general anesthesia, apart from obviating the dangers of this technique in poor risk patients, maxillary nerve block offers other advantages. First, bleeding is minimized. This effect is enhanced by use of a controlled quantity of epinephrine than is possible with certain inhalation anesthetics. Second, the absence of an oral-endotracheal tube eliminates competition for the same field between surgeon and anesthesiologist. Moreover, because the laryngeal reflexes are preserved, the airway is protected from blood, tissue fragments, and packs, both during the operation and in the early postoperative period. Third, with regional anesthesia, several of the procedures that have been discussed may be performed expeditiously and less expensively in the office rather than in the hospital.3 Technique: The maxillary nerve can be blocked after it exists the foramen rotundum as it enters the pterygopalatine fossa. Several techniques of approach to this nerve will be described: A. Intraoral route 1. Around tuberosity; High tuberosity technique4 47
2. Through the greater palatine foramen and canal5 B. Extraoral route 1. By way of the sigmoid notch of the mandible6 2. Anterior to the coronoid proces of the mandible7 The very multiplicity of techniques suggest that maxillary nerve block may be frequently unsuccessful or associated with complications. Indeed, elaborate anatomic measurements have been described to facilitate blockade of the nerve, these being deemed essential to insure success and to prevent complications; but the measurements of one author have not always led to reproducible results in the hands of another. Intraoral: Of the two approaches, the first to be discussed is made through the greater palatine foramen. The location varies anteroposteriorly from between the first and second molars to between the second and third molars. On occasion, it can be slightly anterior or posterior to these points. Clinical observations that facilitate finding the foramen have been evolved. Antero-posteriorly, the foramen is always in line with the hamular process of the pterygoid bone. Laterally the foramen is located at the junction of the horizontal plate of the palatine bone and the alveolar process. How far superiorly to insert the needle? Measurements evolved so accurately by Jorgensen8 have been relied on. They consist of measuring the distance from the infraorbital margin to the gingival margin of the maxillary second bicuspid on the same side that the injection is to be made. Three millimeters are subtracted and the remainder is used as the appropriate needle distance. The foramen is entered and the needle advanced to the preset marker (any resistance should not be overcome by force, but the needle should be withdrawn slightly and again advanced very slowly-if continued resistance is met, regardless of how slight, the attempt should be discontinued9 2 to 3 cc of anesthetic solution is injected after aspirating to avoid intravascular deposit. Maximum anesthesia is obtained in 5 to 15 minutes. The second intraoral approach is known 48
as the high tuberosity technique. With a retractor, or the forefinger of the left band placed at the angle of the mouth, the cheek is retracted upward and backward to permit exposure of the first molar tooth.10 The needle is inserted into the mucosal reflection above the first upper molar and is then advanced in a direction backward, upward, and inward, tangent to the tuberosity of the maxilla, so that it makes an angle of approximately 40 degrees with the sagittal plane of the head. The point of the needle loses contact with the bony surface at a distance of 3 to 4 cm. from its point of entry. It is then introduced 0.5 cm. further, and after aspirating, 2 cc. of anesthetic solution is slowly injected. Extraoral: There are basically two ways of approaching the maxillary nerve in the sphenomaxillary fossa by the lateral or zygomatic route: 1. The zygomatic arch is bisected and a wheal is raised just below this bisector. An 8 cm. 22 gauge needle which has been threaded with a rubber recorder is introduced through the wheal in a direction normal of the median plane of the head, and advanced deeply until it makes contact with the lateral plate of the pterygoid process. The bone is felt ordinarily when about half the length of the needle has disappeared into the tissues. The recorder is then set 1 cm. from the surface of the skin, the needle is then withdrawn until its point reaches the subcutaneous tissues, so that its direction may be changed, and it is then reintroduced and inclined slightly forward toward the sphenomaxillary fossa until the recorder reaches the surface of the skin. If no bony contact is now obtained, the point of the needle is in the sphenomaxillary fossa. The aspiration test is performed, and if negative, 2 cc. of anesthetic solution is injected."l 2. A 4 cm. 24 gauge needle is introduced into the angle formed by the anterior border of the coronoid process of the ascending ramus of the mandible with the lower margin of the zygoma.'2 The needle is introduced transversely and directed slightly upward toward the tuberosity of the maxilla. After making contact with the bone, it is withdrawn, sufficiently so that its direction may be changed and it may
ANEsTHEsiA PROGRESS
be reintroduced inclined backward to a slight degree until it is felt entering the sphenomaxillary fossa, immediately after losing contact with the maxilla. The needle is then at a depth of approximately 5 or 6 cm. from the skin surface. The general direction of the needle is then upward, backward, and toward the apex of the orbit. After making the aspiration test, 2 cc. of anesthetic solution is then injected. Hematomas of the cheek are not infrequent when performing this block. Complications: Apart from those complications which are common to all types of nerve blocks, specific complications of maxillary nerve block include exophthalmos, edema of the eyelids, anesthesia of the ophthalmic nerve and paralysis of the abducens nerve-all of which obviously are undesirable, but most likely due to the injection of excessive volumes of solutions too high into the sphenomaxillary fossa. Other complications include the accidental penetration of the orbit and intraorbital injection, intracranial injection, and deposition of anesthetic solution into subarachnoid space with consequent unconsciousness.13 Of all the possible complications of maxillary nerve block, the most important one is the failure to recognize apnea, which is induced by subarachnoid injection, and consequent failure to institute assisted respiration until spontaneous respiration returns. As meningitis also is a potential sequel to intracranial penetration, antibiotics should be given in such cases. Conclusion: The maxillary nerve block has been investigated with regard to the possibility of its utilization in the office of the general practitioner, and feasibility of its routine use within the environment of a dental school. The most popular techniques for obtaining this block have been described briefly. The application of this injection may be advantageous to the dental patient in terms of reduced psychological trauma when used in conjunction with adequate intravenous conscious sedation. Although the possibility exists for the routine use of the V2 block in the office of the general practitioner, it appears the technique can be most useful to practitionMARCH-APRIL, 1977
ers of oral surgery, either in the hospital or office setting, especially if combined with intravenous conscious sedation. It has proved effective, dependable, and safe in some 4,900 cases.1415, However, because of the possibility of rare but potentially serious complications, maxillary nerve block should be performed only in situations where personnel experienced in resuscitative measures, and necessary equipment are available. BIBLIOGRAPHY 1. Poore T E Maxillary nerve block-a useful technique J Oral Surg Oct 1973. 2. Ibid Poore p 750 3. Ibid Poore p 750 4. Adriani J Labat's Regional Anesthesia, its technique and clinical application Phila W B Saunders Co 1976 5. Stebbins H N and Burch R J Intraoral and extraoral injections J Oral Surg Jan 1961 6. Ibid Adriani p 92 7. Ibid Adriani p 94 8. Ibid Stebbins p 23 (see below) 9. Monheim L M Local anesthesia and pain control in dental practice, C V Mosby Co 1969 10. Ibid Adriani p. 96 11. Ibid Adriani p 92 12. Ibid Adriani p 94 13. Ibid Poore p 754 14. Ibid Poore p 749 2,900 Maxillary nerve blocks performed over 10 year period at Mayo Clinic. 15. Ibid Stebbins p 22, Over 2,000 cases of Maxillary nerve block over 5 year period at Lackland Air Force Base Texas. 8. Jorgensen N B Measurements for intraoral block of the maxillary nerve. J. Oral Surg Jan 1948
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ANNOUNCEMENT Stanley R. Spiro, D.D.S., of Hempstead, N.Y., has been appointed as consultant/ expert in dental anesthesiology to the: Division of Surgical-Dental Drug Products of the Bureau of Drugs, Food and Drug Administration Department of Health, Education, and
Welfare, Rockville, Maryland 49
