Meshram v.S. 2013

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Hindawi Publishing CorporationAsian Journal o NeuroscienceVolume , Article ID ,pageshttp://dx.doi.org/.//

Research ArticleAssessment of Nerve Injuries after Surgical Removal ofMandibular Third Molar: A Prospective Study

Vikas Sukhadeo Meshram,1 Priyatama Vikas Meshram,2 and Pravin Lambade1

Department o Oral and Maxilloacial Surgery, Swargiya Dadasaheb Kalmegh Smruti Dental College and Hospital,Road Hingna-Waddhamna, Hingna, Nagpur, Maharashtra , India

Department o Conservative Dentistry and Endodontic, Swargiya Dadasaheb Kalmegh Smruti Dental College and Hospital,Road Hingna-Waddhamna, Hingna, Nagpur, Maharashtra , India

Correspondence should be addressed to Vikas Sukhadeo Meshram; [email protected]

Received July ; Accepted September

Academic Editors: M. Kondo and M. Miscusi

Copyright Vikas Sukhadeo Meshram et al. Tis is an open access article distributed under the Creative CommonsAttribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work isproperly cited.

Although third molar extraction is a routinely carried out procedure in a dental set-up, yet it is eared both by the patient andthe dentist due to an invariable set o complications associated with it, especially in the orm o nerve injuries. Hence, prior toperorming such procedures, it would be wise i the clinician thoroughly evaluates the case or any anticipated complications sothat adequate preventive measures can be taken to minimize the traumatic outcomes o the procedure and provide maximumpatient care, which would urther save the clinician rom any sort o litigation.

1. Introduction

Impacted teeth can be dened as those teeth whose normaleruption is prevented by adjacent tooth, overlying bone orsof tissue, malpositioning and lack o space in the arch,or other impediments. Impacted mandibular rd molar isone o the most common ndings which is detected onroutine dental checkup. However the patient seeks treatmentwhenever there is pain, swellings or another discomort.

Although the overall complication rate is low and mostcomplications are minor, third molar removal is so commonthat the population morbidity o complications maybe signi-icant. As such, efforts to limit intraoperative or postoperativecomplications may have a great impact in terms o enhancingpatient outcome.

Impacted mandibular third molar teeth are in closeproximity to the lingual, inerior alveolar, mylohyoid, andbuccal nerves (Figure ). During surgical removal, each othese nerves is at risk o damage, but the most troublesomecomplications result rom inerior alveolar or lingual nerveinjuries. Te majority o injuries result in transient sensorydisturbance but, in some cases, permanent paraesthesia

(abnormal sensation), hypoesthesia (reduced sensation), or,even worse, some orm o dysaesthesia (unpleasant abnormalsensation) can occur.

Tese sensory disturbances can be troublesome, causingproblems with speech and mastication and may adverselyaffect the patients quality o lie. Tey also constitute as oneo the most requent causes o complaints and litigation [].

2. Material and MethodsTe prospective study data was collected rom patients

visiting the Department o Oral and Maxilloacial Surgery,Swargiya Dadasaheb Kalmegh Smruti Dental College & Hos-pital, Nagpur, or surgical extraction o impacted mandibularthird molar. In this study, preoperative predictive variableswere recorded with data recordo name, age, gender, andtypeo impaction. Postoperative assessment was done afer oneweek at the time o suture removal or paresthesia/anesthesiaby questioning about tongue, chin, and lip sensibility andperorming neurosensory tests like -point discrimination,pinprick, and light touch. Patients with neurosensory distur-bance were ollowed up or six months.

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Asian Journal o Neuroscience

(a) (b)

F : wo-point discrimination test.

(a) (b)

F : Pinprick test.

At the postoperative visit, each patient was specicallyasked i there was any difference in sensation o lowerlip or chin between operated and unoperated sides. Alsospecic questions were asked about accidental biting o lips,drooling/ood running down the chin, and burning, painul,

or tingling sensations.Nerve injury assessment ollowing clinical neurosensory

tests was used. Beore and during testing, the subject wasasked to close the eyes and tests were perormed [ ].

.. wo-Point Discrimination est (PD). In this neurosen-sory test, the probes o caliper device were drawn acrossthe surace o skin or mucosa at constant pressure andpatient was asked whether one or two points are elt. Oneat a time blunt dual probes were applied to the skin ormucosa, and the subject was asked to raise his lef hand itwo points were sensed. Te minimum separation that wasconsistently reported as two points was termed as two-point

discrimination threshold. Te separation distance at whichthe subject was capable o distinguishing two points in veor six trials was recorded or that particular zone. Wheneverincorrect answers were given, the probe with the next largeseparation distance was selected. Whenever correct answers

were given, probe with the next smaller separation distancewas selected (Figure).

.. PinPrick est (PP). In this test, a sharp dental probewas applied to the skin in a quick pricking movement andpain perception o the patient was assessed. Each test areawas pricked three times bilaterally, and subject was askedi any difference was elt between the sides. Sensation waschecked by pricking tongue, mucosa, lip, and skin over chinregion. Paresthesia was dened as any postoperative changein sensitivity o tissues innervated by the trigeminal nerveafer test evaluation (Figure).

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F : Light touch assessment.

.. Light ouch Assessment (L). Tis method was used ortesting by gently touching (tactile stimulation) the skin andevaluating the detection threshold o the patient. For thistest,cottonstick wasused to perorm the test. Stimuli were appliedat randomly and area o anesthesia was mapped by movingoutward in small steps until stimulus is elt [] (Figure).

3. Results

Te prospective study data was collected rom patientsvisiting the department o Oral and Maxilloacial surgery,Swargiya Dadasaheb Kalmegh Smruti Dental College & Hos-

pital, Nagpur, or surgical extraction o impacted mandibularthird molar.Out o patients, were male patients and were

emale patients. Patients age ranged rom to with meano . years (able). Out o total patients, (.%)patients had mesioangular type o impaction, (.%)were horizontal, (.%) were vertical, (.%) patientshad distoangular impaction, and (.%) patient each olinguoversion and inverted type o impaction (able).

Lingual nerve paresthesia was reported in patients(.%) out o cases, and the type o impaction washorizontal class II, position C and Disto-angular class II,position A. inerior alveolar nerve paresthesia was reported

in patient (.%) having mesio-angular, class II, positionA type o impaction (able).

4. Discussion

Te surgical removal o impacted mandibular third molarsis one o the most commonly perormed dentalveolar pro-cedures in oral and maxilloacial surgery. Invariably, thesurgeon may ace various complications associated with thesurgical removal o impacted mandibular rd molars, amongwhich major postoperative complication is neurosensarydecit. It may affect either the inerior alveolar nerve ormore commonly the lingual nerve that leads to numbness

: Gender distribution.

Gender N %

Male .%

Female .%

otal %

: Angulations o rd molar impaction.

ype o impaction No. o patients Percentage

Mesioangular .%

Horizontal .%

Vertical .%

Distoangular .%

Linguoversion .%

Inverted .%

: Sample distribution o nerve damage complication.

Nerve injury Males Females IncidenceLingual nerve .%

Inerior alveolar nerve .%

o the ipsilateral anterior two-thirds o the tongue and tastedisturbance [].

In a landmark article by Howe and Poyton [] in , itwas determined afer evaluating , impacted mandibularmolars clinically at the time o extraction and radiograph-ically that a true relationship existed in approximately .percent. A true relationship was dened as the visualizationo the neurovascular bundle at the time o tooth removal.An apparent relationship was dened by radiographs as acircumstance in which the roots o the teeth appeared to bein an intimate relationship to the IAN. Tis occurred in .percent o the teeth.

O the cases that developed postsurgical nerve impair-ment, over percent o them had a true relationshipwhich represented . percent incidence. Tis was a times greater incidence than that occurring with those teethexhibiting an apparent one. Tey urther noted increasedincidences in older patients: teeth that were deeply impacted,those which exhibited grooving, notching, or peroration,anda three- andour-time increase in mesial andhorizontallyimpacted teeth with linguoversion [].

In , Rood and Nooraldeen Shehab [], in a literaturereview, collected seven radiographic indicators o a closerelationship between the impacted rd molar and the inerioralveolar canal. Four signs were observed in the tooth root(darkening, deection and narrowing o the root, and a bidroot apex) andthe other three in the canal (diversion,narrow-ing, and interruption in the white line o the canal)(Figure ).Te authors collected retrospective data on patientsand prospective data on , observing the appearance osome o the radiographic indicators o a close relationshipbetween the impacted rd molar and the inerior alveolarcanal in the OPG in .% and .% o cases, respectively.In the retrospective study, nerve damage was statistically

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(a) (b)

(c) (d)

(e) ()

(g)

F : Relationship o inerior alveolar nerve with roots o impacted third molar. (a) Darkening o root. (b) Deection o root. (c)Narrowing o root. (d) Bid root apex. (e) Diversion o canal. () Narrowing o canal. (g) Interruption in white line o canal.

related to all the radiographic signs except bid root apexand darkening o the canal. In the prospective study, nervedamage was related to diversion o the canal, ollowed bydarkening o the root and interruption o the canal.

Unintended iatrogenic injury to the lingual nerve mayhappen during third molar surgery due to the anatomical

proximity o the cortex region o the molar to thenerve, beingseparated rom it by the periosteum alone (Figure).

Although the symptoms may resolve with time in most othe cases, an estimation o the type o injury has to be madeto establish the treatment plan and allow recovery. Judgmentcan be made based on various systems or classication o

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F : Vital structures in relation to the impacted rd molar.

nerve injuries, rst among which to be introduced in was Seddons classication that involves the ollowing threecategories.

() Neuropraxia. It is an interruption in conduction o theimpulse down the nerve ber. Te recovery in such casestakes place without Wallerian degeneration, and, hence, it isconsidered to be the mildest orm o nerve injury.

() Axonotmesis. It is losso the relative continuity o the axonand its covering o myelin, but preservation o the connectivetissue ramework o the nerve.

() Neurotmesis.It is loss o continuity o not only the axon,

but also the encapsulating connective tissue [].

Another system was given by Sunderland in []which includes ve classes as ollows.

First Degree.It is similar to Seddons neuropraxia and due tocompression or ischemia, a local conduction block and ocaldemyelinization occur which recovers in - weeks.

Second Degree. It is similar to Seddons axonotmesis andrecovery occurs at the rate o mm/day as the axon ollowsthe tubule.

Tird Degree. In this class, the endoneurium gets disrupted

while the epineurium and perineurium remain intact. Recov-ery may range rom poor to complete and depends on thedegree o intraascicular brosis.

Fourth Degree.In this class there is an interruption o all theneural and supporting elements although the epineuriumisintact and the nerve becomes usually enlarged.

Fifh Degree.Tis class involves a complete transection o thenerve with the loss o continuity [].

Most studies have shown that i the paresthesia ollowsextraction, it is likely to be temporary and to be resolvedwithin the rst months. However, i no improvement isseen afer years o ollowup, the altered sensation is likely to

represent nerve dysunction that may be in the orm o per-manent neurosensory disability, a complete loss o sensoryunction, and neurogenic symptoms [,]. Nevertheless, itseems that compression should not cause anesthesia or morethan months and sectioning should not cause anesthesia ormore than months. Anesthesia without improvement afer

month is also very likely to leave some permanent residualimpairment. Te variable rate o recovery and improvementin symptoms could be explained by the act that IAN or LNinjuries differ in type. Te lesions that recover within the rst months are probably neurapraxias or Sunderland rst- orsecond-degree injuries, which are more common, and long-standing injuries could represent more severe axonotmesisor Sunderland third- or even ourth-degree injuries. Delayedrecovery rom IAN injuries afer more than year has alsobeen reported in the literature.

Te incidence o reported postoperative dysaesthesia othe inerior alveolar and the lingual nerve varies widelyin the studies published so ar. In a study published in

by Gargallo-Albiol et al., the incidence o temporarydisturbances affecting the IAN or the LN was ound to be inthe range rom .% to % [].

In another study by Zuniga, the incidence o permanentinjury to the IAN and LN has been mentioned to all inthe range between .% and % and .% and .%,respectively []. ay and Go carried out a study in todetermine the incidence o inerior alveolar nerve paraes-thesia in those patients where an exposed inerior alveolarnerve bundle is seen during third molar surgery, and it wasconcluded that such a situation hints a high probability o anintimate relationship o the nerve with the tooth and carriesa % risk o paraesthesia with a % chance o recovery by

one year rom surgery [].Recently Cheung et al. carried out a study in which it was

seen that o all the lower third molar extractions perormedby various grades o operators, .% developed IAN decitand .% developed LN decit. It concluded that distoan-gular impaction was ound to increase the risk o LN decitsignicantly, wherein the depth o impaction was related tothe risk o IAN decit. On the other hand, sex, age, raising oa lingual ap, protection o LN with a retractor, removal odistolingual cortex, tooth sectioning, and difficulty in toothelevation were not ound to be signicantly related to IAN orLN injury [].

Te study o Anwar Bataineh showed postoperative

lingual nerve paresthesia that occurred in .% patients.Tere was a highly signicant increase in the incidenceassociated with raising o a lingual ap. Te incidence oinerior alveolar nerve paresthesia was .%. Te results othis study concluded that the elevation o lingual aps andtheexperience o the operator are signicant actors contributingto lingual and inerior alveolar nerve paresthesia, respectively[].

Considering angulation o third molars in our caseseries, teeth with mesial angulations were reported in .%,horizontal angulation in .%, vertical angulation in .%and distoangulation in .%, one case each o lingual versionand inverted is also noted.

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Te depth o the impacted mandibular third molar andits lingual angulation are other actors which may affect theprobability o nerve damage occurring. Eduard Valmaseda-Castellon et al. carried out a study to assess the risk o lingualnerve injury afer surgical removal o lower third molars andconcluded that anatomical actors such as lingual angulation

o the third molar, surgical maneuvers such as retraction othe lingual ap, or vertical tooth sectioning, and surgeoninexperience all increase the risk o lingual nerve damage,although permanent lesions seem to be very rare [].

In our study, out o total patients, patents reportedwith lingual nerve paresthesia (.%) which having horizon-tal class II, position C and Disto-angular class II, position Atype o impaction and patient were o inerior alveolar nerveparesthesia having mesio-angular, class II, position A type oimpaction.

Various actors are responsible or the injury to theinerior alveolar nerve and lingual nerve in third molarsurgery. In our study, incidence o injury to IAN and LN

was comparatively very low, and all cases were o transientparesthesia. All the precautions should be taken to preventthe injury to the inerior alveolar nerve or lingual nerve.

5. Conclusion

Mandibular third molar extraction is a very commonlycarried out procedure in day-to-day dental practice andis undoubtedly associated with ew risks especially neuralinjuries and thereore in the light o the existing evidence,adequate preoperative evaluation o the patient and metic-ulous surgical technique with minimum handling o thelingual ap are o paramount importance to diminish the

incidence o nerve injury.

Although third molar surgery is a secure and low mor-bidity procedure, the risk o complications will always existand it increases with increased surgical difficulty; hence, thepatient shouldalways be educatedaboutthe risks andbenetso surgery in order to ensure adequate surgical managemento impacted mandibular third molar.

Acknowledgment

Te authors are grateul to Dr. Anisha Maria Madam orassistance in the design o the study, Proessor and HOD,

departmento Oral and Maxilloacial Surgery, Rishiraj DentalCollege and Hospital, Bhopal, India.

References

[] R. Sharma, A. Srivastava, and R. Chandramala, Nerve injuriesrelated to mandibular third molar extractions, E-Journal oDentistry, vol. , no. , .

[] J. Gargallo-Albiol, R. Buenechea-Imaz, and C. Gay-Escoda,Lingual nerve protection during surgical removal o lowerthird molars: a prospective randomised study, InternationalJournal o Oral and Maxilloacial Surgery, vol. , no. , pp. , .

[] J. Howe and H. Poyton, Prevention o damage to the inerioralveolar dental nerve during the extraction o mandibular thirdmolars,British Dental Journal, vol. , article , .

[] J. P. Rood and B. A. A. Nooraldeen Shehab, Te radiologicalprediction o inerior alveolar nerve injury during third molarsurgery,British Journal o Oral and Maxilloacial Surgery, vol., no. , pp. , .

[] S. Sunderland, A classication o peripheral nerve injuriesproducing loss o unction,Brain, vol. , no. , pp. ,.

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[] J. R. Zuniga, Managemento thirdmolar-related nerve injuries:observe or treat? Alpha Omegan, vol. , no. , pp. ,.

[] A. B. G. ay and W. S. Go, Effect o exposed inerior alveolarneurovascular bundle during surgical removal o impactedlower third molars,Journal o Oral and Maxilloacial Surgery,vol. , no. , pp. , .

[] L. K. Cheung, Y. Y. Leung, L. K. Chow, M. C. M. Wong, E. K.K. Chan, and Y. H. Fok, Incidence o neurosensory decitsand recovery afer lower third molar surgery: a prospectiveclinical study o cases, International Journal o Oral andMaxilloacial Surgery, vol. , no. , pp. , .

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