Guideline for maxillofacial impairment rating of trigeminal nerve damage in the Korean alveolar nerve damage, which is quite frequent, it may be reaso

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1 SPECIAL ARTICLE pissn eissn Guideline for maxillofacial impairment rating of trigeminal nerve damage in the Korean Committee of Guides for Maxillofacial Impairment Rating Korean Association of Oral and Maxillofacial Surgeons (KAOMS) Abstract (J Korean Assoc Oral Maxillofac Surg 2012;38:384-93) The trigeminal nerve, one of the cranial nerves, innervates the maxillofacial area and has three branches: the ophthalmic, maxillary, and mandibular nerves. Paresthesia, due to damages to the inferior alveolar nerve and mental nerve (branches of the mandibular nerve), is quite frequent in dental implants and third molar extractions. As medical disputes are increasing, it is necessary to formulate an objective and reasonable disability evaluation. When evaluating the frequent rate of impairment for inferior alveolar nerve damage, it may be reasonable to follow the criteria for the rate of maxillofacial impairment of the American Association of Oral and Maxillofacial Surgeons (AAOMS) - the most scientific and reputable criteria based on the American Medical Association (AMA). Therefore, the Committee of Guides for Maxillofacial Impairment Ratings, in the Korean Association of Oral and Maxillofacial Surgeons (KAOMS), is trying to suggest more reasonable and realistic guidelines for evaluating impairments by reviewing the current evaluation criteria and those of AMA and AAOMS. Key words: Trigeminal nerve, Guideline, Impairment, Rating [paper submitted / accepted ] I. Introduction As one of the cranial nerves, the trigeminal nerve innervates the sensation of the maxillofacial area and has three branches: ophthalmic, maxillary, and mandibular nerves. Paresthesia due to damage to the inferior alveolar nerve and mental nerve, a branch of the mandibular nerve, is quite frequent with regard to dental implant and third molar extraction. In the United States, the incidence of inferior alveolar nerve paresthesia associated with third molar extraction has been reported to be %, and that in Korea was, according to a study in 2009, %. The McBride impairment assessment system - which has been used as standard criteria for evaluating inferior alveolar nerve disturbances - has been published since the 6th edition in Current medical knowledge is immensely different Kyung-Gyun Hwang Department of Oral and Maxillofacial Surgery, Department of Dentistry, College of Medicine, Hanyang University, 222, Wangsimni-ro, Seongdong-gu, Seoul , Korea TEL: FAX: hkg@hanyang.ac.kr CC This is an open-access article distributed under the terms of the Creative Commons Attribution Non-Commercial License ( which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. from that in the 1930s when the McBride impairment assessment system was first established, and the criteria do not include all the changes made in medical sciences since then. The development of clinical technique and medical science of evaluating and treating impairments and new approaches to treating impairments may explain why the McBride impairment assessment system has not been revised since the 6th edition in In Korea, the McBride impairment assessment system is still very much used in determining the rate of impairment. In addition, the impairment evaluation system by the State Tort Liability Act (National Compensation Law), which is often used in evaluating the rate of impairment together with the McBride system, is patterned after the former Japanese tort liability system. The Act has many flaws, e.g., it does not reflect the influences from jobs, it is not much detailed in evaluating the impairments of the maxillofacial area including teeth, the impairment classification is abstract, and the rates of losses among different classes are too great. In addition, the dental implant - which is very much used for recovering lost tooth - is never considered in the National Compensation Law. Medical disputes are currently on the rise; hence the need to formulate objective, reasonable disability evaluation. In particular, when evaluating the rate of impairment for inferior 384

2 Guideline for maxillofacial impairment rating of trigeminal nerve damage in the Korean alveolar nerve damage, which is quite frequent, it may be reasonable to follow the criteria for the rate of maxillofacial impairment of the American Association of Oral and Maxillofacial Surgeons (AAOMS) since the criteria are based on those of the American Medical Association (AMA), which are the most scientific and reputable. Therefore, the Committee for the Guide to Maxillofacial Impairment Rating in the Korean Association of Oral and Maxillofacial Surgeons (KAOMS) is trying to suggest a more reasonable, realistic guideline for evaluating impairments by reviewing the current evaluation criteria and those of AMA and AAOMS. II. Definition of Physical Impairment On May 22, 2001, the World Health Assembly approved the International Classification of Functioning, Disability, and Health (ICF). This classification was first created in 1980 (called the International Classification of Impairments, Disabilities, and Handicaps or ICIDH at the time) by WHO to provide a unifying framework for classifying the consequences of disease. The ICF classification complements WHO s International Classification of Diseases - 10th Revision (ICD), which contains information on the diagnosis and health condition but not on the functional status. 1. Dictionary definition: Inconvenience caused by blockage or obstruction, something that interrupts progress or setup; a body part is malfunctioning, or a mental defect exists. 2. World Health Organization (1999): Loss and/or malfunctioning of psychological or anatomical structure. 3. Social Security Act of the USA (SSA, 1995): Anatomical, physiological, and mental disorders that can be found in medically allowed clinical and diagnostic tests. 4. AMA (2000): Loss or disability of body parts, organs, and organ functions. 5. Welfare of Disabled Persons Act of Korea (2000): Being limited in everyday life and/or social life for a long time by physical and/or mental disorders. III. Impairment Evaluation (Assessment System) The Impairment Assessment System seeks to evaluate the degree of impairment caused by either disease or injury. The impairment evaluation of the Korean Academy of Medical Sciences (KAMS) requires that the evaluation be scientific, objective, convenient, rational, and realistic. The evaluation should be done when symptoms are stable; if changes in symptoms are expected, re-evaluation should be performed in 2 years. There are various evaluation guidelines, but the McBride, AMA, KAMS, and AAOMS guidelines and the National Compensation Law (State Tort Liability Act) are commonly accepted. IV. Permanent Impairment Rating and Disability Rating Permanent impairment and disability are based on the concepts of WHO in the 1980s. The permanent impairment rating involves evaluating the degree of physical limitation and/or malfunction. The disability rating seeks to evaluate an alteration or the loss of an individual s capacity associated with economic, personal, and social aspects and occupational demands. The guideline for permanent impairment rating currently uses the National Compensation Law (State Tort Liability Act), McBride, and AMA. Recently, in 2011, KAMS suggested an AMA Guideline-based one that had been modified to be apposite to the circumstances of Korea. The disability rating is based on the degree of permanent impairment and is conditional on many different factors such as sex, age, job, and educational background. V. Damage to the Trigeminal Nerve and Permanent Impairment Rating 1. Innervation of the trigeminal nerve As the fifth cranial nerve, the trigeminal nerve is a mixed nerve consisting of sensory fibers that are responsible for the sensation of the skin and mucosal membrane of the head and motor fibers that innervate the masticatory muscles. The main branches of the trigeminal nerve are the ophthalmic, maxillary, and mandibular nerves. Most of the trigeminal nerve fibers are sensory; only some of the mandibular nerve fibers are motor fibers. The following are the areas innervated by the trigeminal nerve and their relation to dental practice: 1) Ophthalmic nerve: The first branch of the trigeminal nerve; innervates the eyeballs and their adnexa (vascular tunic and conjunctiva), skin of the frontal and parietal regions, and nasal mucous membrane. 2) Maxillary nerve: The second branch of the trigeminal nerve; responsible for the sensations of the maxillary skin, 385

3 J Korean Assoc Oral Maxillofac Surg 2012;38: teeth, gum, and mucous membrane and palate. 3) Mandibular nerve: Its motor fibers innervate the masticatory muscles and other small muscles; its sensory fibers innervate the mandibular skin and teeth and tongue mucous membrane. The following are the nerve branches: (1) Meningeal branch: Passes through the foramen spinosum and enters the intracranium; innervates the dura mater. (2) Masseteric nerve: Branches from the mandibular nerve above the lateral pterygoid muscles; crosses the mandibular notch to the deep surface of the Masseter muscle and innervates the Masseter muscle. (3) Deep temporal nerve: One of the motor branches of the mandibular nerve; consists of anterior and posterior and innervates the temporal muscle. (4) Lateral pterygoid nerve: One of the motor branches of the mandibular nerve; innervates the lateral pterygoid muscle. (5) Medial pterygoid nerve: One of the motor branches of the mandibular nerve; innervates the medial pterygoid muscle. (6) Buccal nerve: Innervates the skin over the cheek, buccal gingiva of mandibular molars, and buccal mucosa. (7) Auriculotemporal nerve: It passes medially to the lateral pterygoid muscle and to the neck of coronoid process, and then turns superiorly posterior to the temporomandibular joint. It passes through the parotid gland, and then moves superiorly in front of the external acoustic meatus. It runs with the superficial temporal artery, innervates the skin of the temporal regions and its parotid branches originating in otic ganglion, and serves as secretomotor fibers for the parotid gland. (8) Lingual nerve: It runs along the lateroinferior border of the tongue to the apex of the tongue, including the chorda tympani nerve of the facial nerve adjacent to the origin. It provides taste sensation to the anterior 2/3 part of the tongue as well as secretory function of the submandibular and sublingual gland. (9) Inferior alveolar nerve: It branches at the back of the lingual nerve, and then enters the mandible via the mandibular foramen along with inferior alveolar artery and vessel. The nerve branches are as follows: Mylohyoid nerve: It branches from the inferior alveolar nerve just before it enters the mandibular foramen. It has motor fiber that innervates the mylohyoid muscle and sensory fiber that innervates the skin of the submental and submandibular space. Dental branches: Sensory fiber that innervates the mandibular teeth, buccal gingiva, and periodontium. Mental nerve: As a sensory branch of the inferior alveolar nerve, it emerges at the mental foramen beneath the mandibular second premolar. It innervates the lower lip mucosa and skin, mandibular anterior teeth, and skin of the chin. 2. Medical disputes on paresthesia associated with inferior alveolar nerve damage 1) In 2009, a survey on paresthesia after third molar extraction was conducted among dentists across the nation. The results of the survey showed that, of the 2,577 cases of inferior alveolar nerve paresthesia after third molar extraction, the symptom persisted for 2 years or longer in 8.7%; of the 713 cases of lingual nerve paresthesia, the symptom lingered for 2 years or longer in 10.7% of the cases. 2) Of the 3,290 cases of paresthesia after third molar extraction, the symptom persisted for 2 years or longer in 172 cases, 29.7% of which showed a reduced degree of paresthesia; the area of paresthesia decreased in 8.7%, whereas there was no difference in 43.6%. Those who answered not sure accounted for %. 3) Of those who continued to suffer from paresthesia for 2 years or longer, 56.4% experienced inconvenience in their daily lives; 28.5% were not affected by the symptom in their everyday lives, whereas 2.9% experienced extreme inconvenience that they were unaware of drooling at the mouth. At least 9.3% replied that they were not sure. (Journal of the Korean Dental Association 2009, Vol. 47[4]). 4) Currently, the Court applies the evaluation guideline for trigeminal nerve damage when evaluating mandibular nerve damage and associated permanent impairment. The McBride and AMA guidelines discuss only damage to the entire trigeminal nerve. Recent trends focus on neuralgia and acclimation to nerve damage instead of simply evaluating paresthesia. The State Tort Liability Act has no evaluation criteria for either trigeminal nerve or inferior alveolar nerve; it simply calculates the impairment rate as 30% when there are limitations to mastication and language ability, 15% in case of severe local neurological symptom, and 5% in case of persistent neurological symptom. Besides, the guidelines do not reflect any difference in the rate of loss of labor capacity attributed to job difference. Moreover, in the guideline, the differences in the rate of loss of labor capacity are too great among different classes; hence the need to suggest evaluation criteria that are reasonable and specific to inferior alveolar nerve damage. 386

4 Guideline for maxillofacial impairment rating of trigeminal nerve damage in the Korean 3. Calculating the rates of impairment and labor capacity loss due to inferior alveolar nerve damage 1) McBride evaluation guideline Evaluation guideline Criteria of impairment (Head, brain, spinal cord) Nerve injury I. Brain injury with fracture A.2 5th cranial nerve (trigeminal nerve) sensory paralysis, with facial neuralgic pain A.3 7th cranial nerve (facial nerve) paralysis, disfigurement, language dysfunction A.7 12th cranial nerve (hypoglossal nerve) paralysis, loss of taste and function, dysphagia) Impairment whole person (%) Impairment classification by job Application of rates of impairment and labor capacity loss due to sensory paralysis of one side of the lower lip - Selection of impairment criteria: Apply % impairment rate for the whole body caused by fifth cranial nerve paralysis. - % is applied when both sides of the trigeminal nerves are damaged. Only 9% - half of % - is applied to the case of lower lip paralysis on one side. - 9% is when the entire trigeminal nerve is damaged. Since the mandibular nerve is one of the three branches of the trigeminal nerve, only 3% - 1/3 of 9% - is applied to mandibular nerve damage. - In terms of the rate of loss of labor capacity of the average workers who work inside or outside buildings, both the rate of physical impairment and job coefficient are considered. In this case, 20% loss of labor capacity can be applied in the table of job coefficient (Category 3 Nervous System). Therefore, 20% 1/2 1/3=3.3% can be applied if it is calculated in the same way as that for calculating the rate of physical impairment. - The rate of physical impairment for lower lip paralysis on one side is 3%; the rate of loss of labor capacity may be calculated as 3.3%. 2) AMA Impairment Guideline 4th edition of AMA Impairment Criteria (1993) - Assessment of rates of impairment and labor capacity loss due to sensory paralysis of one side of the lower lip AMA Impairment Guideline 4th edition (1993) Head impairment evaluation (cranial nerve) Trigeminal nerve Completeparalysis unilateral 3-10% Complete paralysis bilateral 20-85% Facial nerve neuralgic pain 10-50% A typical facial pain 0-20% Complete facial paralysis unilateral 3-5% Complete facial paralysis bilateral 30-45% According to the table for evaluating the rate of head impairment of the AMA impairment criteria 4th edition, 3-10% of trigeminal-full loss of sensation on one side class may be applied. 3-10% impairment rate is applied to all three branches of the trigeminal nerve. Since sensory paralysis of the lower lip involves only one of them, i.e., the mandibular nerve, 1/3 may be applied. According to the AMA 4th edition, the rate of impairment may be 1-3.3%. 5th edition of AMA Impairment Guideline (2000) AMA Impairment Guideline 5th edition (2000) Criteria for rating trigeminal or glossopharyngeal neuralgia Class I (0-14%) Classs II (15-24%) Class III (25-35%) Mild uncontrolled facial neuralgic pain that may interfere with ADLs Moderately severe, uncontrolled facial neuralgic pain that may interfere with ADLs Severe, uncontrolled, unilateral or bilateral facial neuralgic pain that prevents performance of ADLs - Sensory evaluation of pain, heat, tactile, or both sides of the face is performed by comparison. - When assessing sensory paralysis due to damage to one side of the mandibular nerve, half (since one side) of the rate for the entire trigeminal nerve damage and 1/3 (since mandibular only) are applied at the same time. - Rate of impairment for class I (0-14%): 0-2.3% - Rate of impairment for class II (15-24%): 2.5-4% - Rate of impairment for class III (25-35%): % - In the aforementioned case, if there is only paralysis of the lower lip, 0-2.3% of the rate of impairment may be applied, 2.5-4%, if accompanied by moderate facial pain, and %, if accompanied by severe facial pain. 3) National Compensation Law (State Tort Liability Act) In the enforcement ordinance of the Act, 1-14 classes of rates of labor capacity loss are defined. The criteria of the Act are a full adoption of the former Japanese system. The criteria are not reasonable in many ways - job influences 387

5 J Korean Assoc Oral Maxillofac Surg 2012;38: are not considered at all, degree of impairment is abstract, and differences in the rates of labor capacity loss are too great among different classes. The assessment of the rate of labor capacity loss according to the number of dental prostheses after tooth loss is quite unreasonable and is not very much used today. In modern dentistry, a lost tooth can be restored with dental implant, which can retain 80% of masticatory ability of a natural tooth and whose aesthetics and convenience are on a par as those of a natural tooth. Therefore, it is not reasonable to assess the rate of labor capacity loss of dental implant restoration as in the past. Criteria for impairment evaluation according to the State Tort Liability Act Criteria rating for impairment of dentistry 1) Class X (30%): Impairment of mastication and language, prosthesis (crown) over 14 teeth 2) Class XII (15%): Sever local paralysis or paresthesia, prosthesis (crown) over 7 teeth 3) Class XIV (5%): Local paralysis or paresthesia, Prosthesis (crown) over 3 teeth < No Criteria Rating of Nerve Implairment on National Compensation Law> Assessment of the rates of impairment and labor capacity loss due to sensory paralysis of the lower lip - The criteria of the State Tort Liability Act do not discuss inferior alveolar nerve damage, so it is not possible to determine the rates of impairment and labor capacity loss by the Act. So far, the rate of labor capacity loss is 5% uniformly for those who have persistent local neurological symptoms, but that needs to be changed. 4) Impairment evaluation criteria of the Korean Academy of Medical Sciences - In the impairment evaluation criteria published by KAMS in 2011, there are no detailed evaluation criteria with regard to trigeminal nerve. Thus, it is not possible to assess the damage to the sensory fiber of the trigeminal nerve, such as lower lip paralysis. 5) Guideline of the American Association of Oral and Maxillofacial Surgeons Criteria for assessing impairment: The criteria, based on the 6th edition of the AMA criteria for impairment assessment, were suggested in 2008 as a guideline for assessing impairment in the oral and maxillofacial areas. Evaluating the impairment for facial neuralgia accompanied by lower lip paralysis related to inferior alveolar nerve damage. 1. Migraine headache: example, p. 343, Table Cranial neuropathies or dysfunction: example p. 40, Table 3-1; p. 343, Table 13-19, a. Trigeminal (V) and Glossopharyngeal (IX) Neuralgia (cranial neuropathies or dysfunction) Mild impairment due to uncontrolled facial neuralgic pain = 3-5% whole person Moderate impairment = 3-5% Severe = 6-10% b. Facial Nerve (p.262, Table 11-5) Complete loss of taste - anterior tongue Mild unilateral facial weakness Mild bilateral facial weakness - Article 2-a of the AAOMS guideline can be applied. - Since there is no indication for one side, half of the trigeminal nerve-related values may be applied. The calculation for the rate of impairment is as follows: - Mild-moderate impairment accompanied by uncontrolled facial neuralgia: % - Severe impairment accompanied by uncontrolled facial neuralgia: 3-5% VI. Conclusion = 1-5% whole person impairment (p. 270) = 1-5% whole person impairment = 11-% whole person impairment or Severe unilateral facial paralysis with 75% or greater facial involvement Severe bilateral facial paralysis with inability to control eyelid closure =25-45% c. Criteria for Rating Miscellaneous Peripheral Nerves,(greater and lesser occipital nerves and greater and lesser auricular nerves), p. 343, Table 13-19; p. 344, Table ). Cranial neuropathies other than trigeminal/glossopharyngeal : p. 343 Chapter 11 and p. 262 Table ) The Committee of Guides for Maxillofacial Impairment Rating in the Korean Association of Oral and Maxillofacial Surgeons (KAOMS) has reviewed various impairment assessment criteria for paresthesia, anesthesia, and facial neuralgia caused by damage to the mandibular nerve, a branch of the trigeminal nerve, to suggest a guideline for more objective and fair impairment assessment as follows: 2) Impairment is assessed at least 2 years after the occurrence of the symptoms caused by inferior alveolar nerve damage. 3) Since many assessment criteria - McBride, AMA, AAOMS, and State Tort Liability Act - are considered together, assessing the rate of impairment at 0-5% is appropriate. Such range should be classified as follows: 388

6 Guideline for maxillofacial impairment rating of trigeminal nerve damage in the Korean Mild Moderate Severe Sensory paralysis or paresthesia 0-1% 1-2% 2-2.5% 4) For an objective evaluation of the aforementioned criteria, more research will be necessary for more scientific and objective methods of assessment. Acknowledgements Facial neuralgic pain 1-2% 2-3% 3-5% The Committee Member of Guides for Maxillofacial Impair ment Rating contributed equally to this work. The members are Sunghee Han (Chairperson), Sang-Chul Chung, Seung-Wook Yang, Won Lee, Hoon Myoung, Jongrak Hong, Yong-ju Ok. References 1. World Health Organization. International classification of impair ments, disabilities, and handicaps. Geneva, World Health Organization; Son MS, Lee KS, Park DS, Won JW, Jung YK. The criteria of impairment rating of Korean Academy of Medical Sciences: commentary and case studies. 1st ed. Seoul: Parkyoungsa; Lee KS. Compensation and rewards of medical judgment: focus on neurological impairment. 4th ed. Seoul: Joongangcopy; Cocchiarella L, Anderson GB. Guides to the evaluation of per manent impairment. 5th ed. Chicago: American Medical Association; Han S. National survey of inferior alveolar nerve and lingual nerve damage after lower third molar extraction. J Korean Dent Assoc 2009;47: American Association of Oral and Maxillofacial Surgeons. Guidelines to the evaluation of impairment of the Oral and Maxillofacial Region. Rosemont: American Association of Oral and Maxillofacial Surgeons; Kim MK. Head and neck anatomy. 5th ed. Seoul: Medical and Dental Publishing;

7 J Korean Assoc Oral Maxillofac Surg 2012;38: 삼차신경손상의장애평가에대한가이드라인 악안면장애평가위원회 대한구강악안면외과학회 I. 서론삼차신경은악안면영역의감각을지배하는뇌신경으로안신경, 상악신경, 하악신경로나누어지며, 하악신경의분지인하치조신경및이신경의손상으로인한감각이상은제3대구치발치및임플란트시술과관련된치과영역의신경손상중에많은빈도를보인다. 미국의경우하악제3대구치발치와관련된하치조신경감각이상의발생률은 % 정도로보고되고, 2009년국내에서조사한연구에의하면, % 정도의발생률을보고하고있다. 하치조신경의손상에대한장애평가는맥브라이드식장애평가를일반적인기준으로사용하고있는데, 이는 1936년맥브라이드교수가저술한이래 1963년 6판을발행한이후절판이되었다. 하지만, 맥브라이드기준제정당시의 1930년대의의학과오늘날의의학수준은상당히많은차이가있지만맥브라이드의기준은이를반영하지못하고있다. 이는현대의학의발달과장애에대한평가및장애의치료방법의발달과새로운형태의치료법이개발과 1963년절판이된이후에근 50년동안개정판이나오지못한점도한이유라생각된다. 우리나라에서는신체장애율을결정하는데있어아직도맥브라이드기준을인용하는예가많다. 맥브라이드식장애평가와더불어국부신경손상에따른장애율의평가에종종인용되고있는국가배상법에의한기준은과거일본의배상및장애제도를그대로도입한것으로서직종별직업내용에따른영향을전혀고려하지않았고, 치아를포함한악안면영역의장애에대한평가에대한세분화된항목이부족하고그장애정도가추상적이며등급간의상실률상의격차가너무크다는불합리성이있다. 특히최근치과임상에서많이사용되는임플란트라는개념이전혀반영이되지못하여 치아상실후보철한개수에따른노동력상실률을일률적으로 5% 로감각이상과동일한장애율을주는것역시합리적인장애의평가로판단하기어렵다. 최근증가추세에있는의료분쟁으로개관적이고합리적인장애평가가필요한실정인데, 특히그빈도가높은하치조신경 ( 삼차신경의분지 ) 의손상에따른장애율의평가에있어, 가장과학적이고공신력있는미국의학협회의기준과이에근거를둔미국구강악안면외과학회의악안면영역의신체장애율기준에준하여구강악안면외과영역에서의 신체장애율을인용하는것이합리적이라할것이다. 이에따라서대한구강악안면외과학회악안면장애평가위원회에서는기존의장애평가의기준과미국의학협회및미국구강악안면외과학회의악안면영역의신체장애에대한검토를통해서이기준에의한보다합리적이고현실적으로적용할수있는장애평가가이드라인을제시하고자한다. II. 신체장애 (physical impairment) 의정의 1980년세계보건기구 (WHO) 에서는장애를기존의질병으로보는시각에서신체장애 (physical impairment), 능력상실 (disability), 사회적불이익 (handicap) 의순으로확대하는 ICIDH를제안하게되면, 2001년에서는능력상실을활동제한이란용어로바꾸는 ICF 개념으로분류정의하게된다. 1. 사전적의미 : 가로막혀걸리적거리는불편, 사물의성립이나진행을방해하는것, 신체기관이본래의제기능을하지못하거나정신능력에결함이있는상태 2. 세계보건기구 (WHO, 1999): 심리적또는해부학적구조또는기능의이상이나소실 3. 미국사회보장법 (SSA, 1995): 의학적으로허용된임상과진단적검사로확인할수있는해부학적, 생리적, 정신적이상 4. 미국의학협회 (AMA, 2000): 신체부분, 장기또는장기기능의소실또는사용불가 5. 대한민국 ( 장애인복지법 ( 법률제5931 호 ) 의제2조 ; 2000): 신체적 정신적장애로인하여장기간에걸쳐일상생활또는사회생활에상당한제약을받는것 III. 장애평가 장애평가란손상또는질병등으로발생한장애정도를평가하는것으로대한의학회장애평가기준에서는과학성, 객관성, 편이성, 합리성, 그리고현실성을기본원칙으로평가를시행하여야한다고보고있다. 평가의시기는증상이고정된상태, 증상의변화가예상되는경우는 2년뒤에재평가를요구한다. 현재사용되는장애평가의기준은여러가지가있지만, 맥브라이드장애평가기준, 미국의학회장애평가기준, 국가배상법에의한장애평가기준, 대한의학 * 국내저자들의이해를돕기위해 Special Article 과동일한내용의논문을국문으로도한번더게재했습니다. 390

8 Guideline for maxillofacial impairment rating of trigeminal nerve damage in the Korean 회의장애평가기준, 미국구강악안면외과학회가이드라인 등이보편적인장애평가의기준으로받아들여지고있다. IV. 장애율과노동상실률 신체장애율과노동능력상실률은 1980 년 WHO 의개념 에서나온것으로장애율은신체의장애및기능저하의정 도를평가하는것이고, 노동능력상실률은경제적, 또는사 회적인면의손실을평가하는것을말한다. 현재사용되 는장애율평가의기준은국가배상법, 맥브라이드의기준 (McBride), 미국의학협회 (AMA) 가정한기준을많이사용 하고있고, 최근 2011 년대한의학회에서도 AMA 기준을한 국실정에맞게정한대한의학회기준을제시하고있다. 노 동상실률은신체장애율에그사람의성별, 연령, 직업, 그리 고교육정도등여러여건을고려해서판단한다. 1. 삼차신경 V. 삼차신경의손상과장애율 삼차신경은제 5 뇌신경으로두부의피부및점막의감각 을담당하는지각섬유와저작근을지배하는운동섬유로구 성되어있는혼합신경이다. 삼차신경의주된가지는눈신 경 (ophthalmic nerve), 상악신경 (maxillary nerve), 하악신경 (mandibular nerve) 로분지되며, 삼차신경의대부분은지각 신경으로구성되어있고, 하악신경의일부가운동신경으로 구성되어있다. 삼차신경의지배영역및치과임상과의관 련성을살펴보면다음과같다. 1) 안신경 : 삼차신경의제 1 지이며, 안구와그부속기 ( 강 막, 안구혈관막의지각, 결막 ) 에분포하고, 전두부와두정 부의피부, 비강의정박에도분포한다. 2) 상악신경 : 삼차신경의제 2 지로상악면부의피부, 구개, 상악치아, 치은및상악부의점막등의지각을지배한다. 3) 하악신경 : 운동성부분은저작근기타 2, 3 의소근 ( ) 으로분포하고, 지각성부분은하악부의피부, 혀의점 막, 하악의치아등에분포하고다음과같이분지된다. (1) 경막지 (meningeal branch 또는 nervous spinosus): Foramen spinosum 을통과하여두개강내로들어가 dura mater 에분포. (2) 교근신경 (masseteric nerve): 외측익돌근 ( ) 위에서하악신경으로부터분지해교근신경이되고하악절 흔중을지나교근의내측면에달한뒤, 교근내에분포. (3) 심측두신경 (deep temporal nerve): 운동지의하나이고 전지와후지가있으며모두측두근에분포. (4) 외측익돌근신경 (lateral pterygoid nerve): 운동지에서 저작근중외측익돌근에분포. (5) 내측익돌근신경 (medial pterygoid nerve): 운동지에서저작근중내측익돌근에분포. (6) 협신경 (buccal nerve): 뺨의피부, 하악구치부의협측치은및협점막에분포. (7) 이개측두신경 (auriculotemporal nerve): 외측익돌근과하악경의내측을지나악관절의뒤에서위로구부러져이하선을관통한후외이도앞을상행한다. 천측두동맥과동반하여측두부피부에분포, 이하선분비는이신경절에서의가지가이신경을통해서이루어짐. (8) 설신경 (lingual nerve): 혀의외하방을따라혀끝까지주행하는데, 기시부근처에서안면신경의가지인고삭신경과합류되어혀의전방 2/3부분의미각과악하선및설하선의분비작용을담당. (9) 하치조신경 (inferior alveolar nerve): 설신경의뒤쪽에서나와, 하치조혈관과함께하악공으로들어가서다음과같은분지를낸다. 악설골근신경 (mylohyoid nerve): 하치조신경이하악공에들어가기직전에분지되어감각신경과운동신경으로구성되어있고, 운동은악설골근에분포하고, 감각신경은이부와악하부의피부에분포한다. 치아가지 (dental branches): 하악의치아와협측치은및치주조직에감각신경은분포한다. 이신경 (mental nerve): 하치조신경의연속으로제2소구치아래에서이공을통해서나오는감각신경이며, 하순의점막및피부, 하악절치, 견치의감각, 턱의피부에분포한다. 2. 하치조신경의손상에따른감각이상의의료분쟁현황 1) 2009년전국의치과의사를대상으로하악지치를발치하고발생한감각이상에대한설문조사를한결과, 조사된지치발치후발행한 2,577건의하치조신경의감각이상중, 2년이상지속된경우가 8.7% 였으며, 조사된설신경의감각이상 713건중 2년이상감각이상지속률은 10.7% 였다. 2) 지치발치후발생한감각이상총건수 3,290건중 2년이지나서도감각이상이지속된 172건중감각이상정도가감소되었던경우가 29.7%, 호소부위가감소되었던경우가 8.7%, 별다른차도없이지속되었던경우가 43.6%, 잘모르겠다고한경우가 % 이었다. 3) 2년이상감각이상이지속되었던경우중일상생활에다소불편했던경우가 56.4% 이었으며, 일상생활에별로지장이없었던경우가 28.5%, 타액이흐르는것도모를정도로일상생활에지장이있었던경우가 2.9%, 직장생활에지장이있을정도로노동력이발생되었던경우는 2.9% 이었으며, 모르겠다고한경우가 9.3% 이었다 ( 대한치과의사협회지 2009년 47권 4호 ). 4) 현재법원에서하악신경손상에대한장애의평가는뇌신경의하나인삼차신경의손상에대한평가를준용하 391

9 J Korean Assoc Oral Maxillofac Surg 2012;38: 고있는실정이다. 맥브라이드장애평가와미국의학협회 의장애평가기준은현재삼차신경전부의손상에의한장 애를평가하는기준만을제시하고있고, 최근경향은단순 한감각이상에대한평가보다는신경손상에의한신경통증 과일상생활에적응여부에초점을맞추고있는실정이다. 국가배상법은삼차신경에대한평가기준이없는상태로씹 는것과언어기능에장해가남은것을 30%, 신경증상은국 부에심한신경증상과신경증상이남은자에대한장애율 을각각 15%, 5% 를산정한것이전부로하악신경손상에의 한장애평가에대한기준은제시하고있지못한다. 그리고 직종별직업내용에따른노동상실률에대한고려가전혀 없고등급간의상실률상의격차가너무크다는불합리성 이있다. 그러므로하악신경손상에대한구체적인합리적 인장애평가기준이제시되어야한다고판단된다. 3. 하치조신경손상에따른신체장애율및노동상실률산출방식 1) 맥브라이드장애평가기준 장애평가기준 치유종료기의장애상태 ( 육체노동자 30 세 ) 기준 ( 두부, 뇌, 척추 ) 신경손상 I. 뇌손상이합병된골절 A.2 5 뇌신경 ( 삼차신경 ) 마비, 안면통을동반 A.3 7 뇌신경 ( 안면신경 ) 마비, 안면추상, 언어기능장애 A.7 12 뇌신경 ( 설하신경 ) 마비, 혀의사용및연하곤란 ) 편측하순지각마비에따른장애율및노동상실률적용 - 장애기준의선택 : A. 2 5 뇌신경 ( 삼차신경 ) 마비에의한 전신장애율의 % 적용 전신장애율 (%) - 전신장애율 % 는양측삼차신경의전체손상에의 한전신장애율로편측의하순마비의경우는 % 의절반인 9% 를적용할수있다. - 전신장애율 9% 는삼차신경전체의손상에의한장애 율로하악신경은삼차신경의세가지중하나이므로 9% 의 1/3 인 3% 를적용할수있다. - 옥내외일반근로자의노동상실률은신체장애율에직 업계수를고려한것으로추가로첨부된직업계수표에서신 경계의신체부위를적용하면 3번의 20% 를적용할수있다. 그러므로신체장애율과같은방식으로계산하면 20% 1/2 1/3=3.3% 를적용할수있다. - 편측하순지각마비는신체장애율 3%, 노동상실률 ( 옥 내외근로자 ) 3.3% 정도로계산할수있다 영구장애의직업에따른분류 ) 미국의학협회 (AMA) 장애기준 미국의학협회장애기준 4 판 (1993 년 ) - 편측하순지각마비에따른장애율과노동상실률산정 미국의학협회장애기준 4판의두부 ( 머리 ) 장애평가 법의표에서 삼차신경 - 한쪽의완전감각상실 항목의 3-10% 장애율을적용할수있다. 3-10% 의장애율은삼차신경의세가지분지모두에적 용되는장애율로하순의지각마비는세가지중에서하악 신경에만관련되는것으로 1/3 을적용할수있다. AMA 4 판에따른신체장애율은 1-3.3% 를산정할수있다. 미국의학협회장애평가기준 5 판 (2000 년 ) - 감각의평가는통각, 온각, 촉각또는얼굴양측을비교 하여평가한다. - 편측하악신경손상에의한감각이상장애는삼차신경 전체장애율의절반 ( 편측 ) 과동시에 1/3( 하악신경에국한 ) 을적용해서산정한다. - Class I (0-14%) 의경우는 0-2.3% - Class II (15-24%) 의경우는 2.5-4% - Class III (25-35%) 의경우는 % 의장애율을적용 시킬수있다. - 상기증례에서단순한하순의마비만있는경우는 0-2.3% 의장애율을적용할수있고, 중등도의안면통증을 동반하는경우는 2.5-4%, 심한안면통증을동반하는경우 에는 % 의장애율을적용시킬수있다. 3) 국가배상법 미국의학협회장애평가기준 4 판 (1993) 두부 ( 머리 ) 장애평가방법 ( 뇌신경장애율 ) 삼차신경 한쪽의완전감각상실 3-10% 양쪽의완전감각상실 20-85% 삼차신경불인통 10-50% 비정형적안면신경통 0-20% 한쪽의완전운동상실 3-5% 양쪽의완전운동상실 30-45% 미국의학협회장애평가기준 5 판 (2000) 제 5 뇌신경 ( 삼차신경 ) 의장애평가기준 Class I (0-14%) Classs II (15-24%) Class III (25-35%) 일상생활활동을방해하는경도의조절되지않는안면신경통증일상생활활동을방해하는중등도로심한, 조절되지않는안면신경통증일상생활활동을수행하지못하게하는고도의조절되지않는편측또는양측안면신경통증 국가배상법시행령으로전체 1-14 급노동력상실률정의 하고있으며, 국가배상법에의한기준은과거일본의제도 를그대로도입한것으로써직종별직업내용에따른영향 을전혀고려하지않았고그장애정도가추상적이며등급 392

10 Guideline for maxillofacial impairment rating of trigeminal nerve damage in the Korean 간의상실률상의격차가너무크다는불합리성이있고치 과쪽에서특히치아상실후보철한개수에따른노동력상 실률의계산은현재불합리하여잘적용되지않는다. 현대 치의학에서상실된치아의수복은치과임플란트의발달로 저작능력이나심미성이나환자의편이성등에서거의자연 치와유사하게회복을할수있으며저작능력의경우도자 연치의 80% 정도회복을할수있어치아상실후임플란트 수복을하는경우노동력상실을과거와같이책정하는것 은합리적이라할수없다. 국가배상법에따른장애평가기준 국가배상법에따른신체장애율중치과관련장애율 1) 제 10 급 (30%): 씹는것과언어기능에장해가남은자, 14 개이상의치과보철을가한자 2) 제 12 급 (15%): 국부에심한신경증상이남은자, 7 개이상의치과보철을가한자 3) 제 14 급 (5%): 국부에신경증상이남은자, 3 개이상의치아에대하여치과보철을가한자 < 국가배상법에는하치조신경손상에대한장애율평가기준이없다 > 하순지각마비에따른장애율과노동상실률산정 - 국가배상법의장애평가기준에서는하치조신경장애 에대한기준이없어국가배상법에의한하치조신경손상에 대한장애율과노동상실률을산정할수는없다. 참고로현 재까지는 국부에신경증상이남은자에대한노동력상실 률을일률적으로 5% 로적용되어왔지만, 이러한부분은 개선을되어야한다고판단된다. 4) 대한의학회장애평가기준 - 대한의학회에서 2011 년에발간한장애평가기준에는 삼차신경과관련된구체적인평가기준이없어하순마비와 같은삼차신경의지각섬유손상과관련된장애평가기준을 적용할수없다. 5) 구강악안면외과학회가이드라인 장애평가기준 : 미국의학회장애평가기준 6판에근거 하여구강악안면영역에관련된장애평가의가이드라인을 2008 년에제시한기준 하치조신경손상과관련된하순마비와동반된안면신 경동통에관한장애평가 - 미국구강악안면외과학회가이드라인에서 2-a 항목을 선택해서적용할수있다. - 장애평가기준에편측적용에관련기준이없어기준 은양측삼차신경에관련된장애의기준의절반을적용하 면, 다음과같은장애율을산정할수있다. - 조절되지않은안면신경동통을동반한경도, 중등도의 장애 : % - 조절되지않은안면신경동통을동반한심한장애 : 3-5% 1. Migraine headache: example, p. 343, Table Cranial neuropathies or dysfunction: example p. 40, Table 3-1; p. 343, Table 13-19, a. Trigeminal (V) and Glossopharyngeal (IX) Neuralgia (cranial neuropathies or dysfunction) Mild impairment due to uncontrolled facial neuralgic pain = 3-5% whole person Moderate impairment = 3-5% Severe = 6-10% b. Facial Nerve (p.262, Table 11-5) Complete loss of taste - anterior tongue Mild unilateral facial weakness Mild bilateral facial weakness VI. 결론 1. 대한구강악안면외과학회악안면장애평가위원회의가이드라인 1) 삼차신경의분지의하나인하악신경의손상에의한 감각이상, 무감각증, 안면동통에적용되고있는여러장애 평가기준을검토하여대한구강악안면외과학회장애평가 위원회에서는보다객관적이고, 공정한장애평가를위해서 다음과같은가이드라인을제안하고자한다. 2) 장애평가의시기는하치조신경손상으로증상이발생 한후최소한 2 년이상이경과한이후의장애상태를평가한다. 3) 신체장애율의평가는맥브라이드기준, 미국의학협회 기준, 미국구강외과학회기준, 국가배상법의기준을종합 적으로고려할때, 전신장애에대한 0-5% 의장애율을산정 하는것이타당하며, 0-5% 의장애구간을아래와같이나누 어평가하는것이타당하다. 4) 상기기준의객관적인평가을위해서는하순의감각이 상및통증에대한과학적이고객관적인평가방법에대한 연구가필요할것으로판단된다. = 1-5% whole person impairment (p. 270) = 1-5% whole person impairment = 11-% whole person impairment or Severe unilateral facial paralysis with 75% or greater facial involvement Severe bilateral facial paralysis with inability to control eyelid closure =25-45% c. Criteria for Rating Miscellaneous Peripheral Nerves,(greater and lesser occipital nerves and greater and lesser auricular nerves), p. 343, Table 13-19; p. 344, Table ). Cranial neuropathies other than trigeminal/glossopharyngeal : p. 343 Chapter 11 and p. 262 Table 경도중등도고도 감각소실및저하 0-1% 1-2% 2-2.5% 안면신경통증 1-2% 2-3% 3-5% 393