Precautions to Take To Avoid Hitting Blood Vessel During Implant Surgery?

What concerns me more is that this might actually be an incisive branch of the mental nerve. I would check the scan again and see if there is perhaps a "secondary" foramen just anterior to the mental foramen. Often times the incisive branch (if present) "dives" back into the symphysis area through this secondary foramen. CT guided surgical templates may be the answer.

Please forward the scan so we can discuss same. If the patient is edentulous then the incisiv branch is insignificant. The biggest concerne is the sublingual artery that penetrates the anterior mandible next to the genial tubercles. I spend some of my time teaching anatomy with Dr. Mohamad Sharawy from MCG, (wrote the anatomy section in Misch's text books). The chance of you hitting the mental nerve is minimal in the anterior aspect of the mandible as most studies show that the closest the mental nerve/foramen is 48 mm apart. The biggest concerns you have are "do not perforate the lingual cortex", do not hit the sublingual artery if they exist next to the genial tubercles and if you do you will get a sublingual swelling. The best way to stop it is to pull the tongue out as far as you can and this will pull the artery over the superior aspect of the hyoid bone and stop the bleedere. Be prepared to hold the tongue for 10 minutes. If all else fails then apply pressure at the carotid artery located next to the adams apple in the fossa. You can palpate your own. It is sort of like turning off the spicket at the main valve at the street feeding you house. You can then transport the patient. This is of course a last resort however it is apparent that you are beginning with implants which is fine, just continue to seek trained supervision. I will be more than happy to review your CT scan. I routinely expose the Mental nerve, this is the safest way. Dr. Duke Aldridge MAGD, MICOI

Agree with previous - do NOT perforate the lingual plate and you should not have a problem. I don't know how many implants you have placed but, in the OR with the patient completely flat, it can sometimes be difficult to get the right angle as there is a tendancy to drill parallel to the floor. Always keep in mind the depression at the lingual inferior aspect of the mandible. This is usually where perforations will occur. If you have any doubt, considering how close the vessel appears, I would consider a guided stent. At the least, make sure that you palpate the depression both superior and inferior before you decide on your final angulation. Best of luck, Ryan

Why not use a shorter implant or graft prior/during the procedure? You can also use a smaller diameter fixture and angle it slightly away from the vital structures, correcting it prosthetically. You can only push this option so far, though. Why in the OR?

The key word will be direct access and visualization.If you want to make sure where you are and not perforating the lingual plate reflect the flap in order to view where you are.palpate the lingual aspect and you will avoid complications.

Dr. Ziv Mazor, Excellent points to consider.

Dr. B, if you are really concerned about the probability of damaging the regional nerves and vessels, then why don't you take advantage of the computer guiding technology (e.g. Simplant) for precision and safe placement?

Agree with Dr.Jafari. When ever you are dealing with tight space,whether it is a vital structure in the vicinity or just adequate bone volume for specific sizes of implants,computer guided surgery is the way to go.Just make sure you have a stop on all your drills. Easiest way to make a custom made stop is use of acrylic resin stops on your drills,or use a system with stops built in to drills.Good luck.

Ziv major, reflecting the lingual flap , sometimes, can itself induce severing of artery & haemorrage. I dont think that's a good idea. dr B , u have to use short implants atleast 3-4 mm short of artery ( practically it is very difficult maintain just 2mm short of vessels as theory goes). or else angulate the implant not more than 25 degrees best way to do it is to use computer guided surgery, computer guided surgery if not available, calculate the angulation on ct scan & transpolate to the cast & make drill guides on the casts.

I think Satish Joshi has a better idea. Make a chairside stop on the drill and get a correct measurement and angulation from CT scan and you want go wrong.Your stop will prevent you from going deeper than required. No need to worry about lingaul flap.

I mean you will not go wrong.

A full lingual reflection of the lingual flap is not always the best idea. The writersf original concern is a large artery in the anterior mandible. As one who does routine dissections at numerous dental schools there are no known major arteries within the osseous structure of anterior mandible (intraforaminal) to be concerned about. The exception is the terminal branch of the sublingual arteries that enters the anterior mandible on either side of the genial tubercles. This will indeed show up on a CT scan with a software program such as Materialase/Simplant. In this case I would relocate the implant to another location and/or use a shorter implant. The writer states that he is going to place two implants in the anterior mandible.........A lower overdenture, replace two incisors, etc? I don't like to routinely reflect the lingual soft tissue down to the myohyoid (sublingual space) due to an increased risk of increased bleeding. Are you sure that you are looking at large blood vessels and can you trace them on your scan? More specifics as to final prosthesis etc may let some of us help you in your planning. A surgical guide stent is a great idea and you may want to use same. Duke Aldridge, DDS, MAGD, MICOI Assistant Professor OHSU

How do you know that what you are looking at is in fact an artery? The only way to say for sure if there is a vessel is to do an angiogram. And I don't think that is necessary. There should not be any major intrabony vessels in the anterior mandible. If there is something that concerns you, then I would go over the study with a qualified radiologist or perhaps repeat the study altogether.

I just know this is going to raise some comment... I am a GP, I work in a public hospital and the majority of my implant cases are anterior mandibular implants for 'locator' supported, overdentures. As advised by a maxillo-facial mentor friend, osteotomy prepartion in the anterior edentuluos mandible regularly involves trashing through the anterior nutrient arteries. Depending on their size, some bleed a little and some bleed a lot - but they all stop bleeding when you bung in the implant. I always know that a 'lot of bleeding' is not due to my penetrating through the lingual plate, because (as advised ) I always raise a lingual flap (though not always involving the midline with severely resorbed mandibles) and for extra safety I like to slide in a curette to gently retract all lingual tissue away while the osteotomy is prepared. Very occasionally when raising the flap, small terminal branches of the lingual artery are encountered on the lingual aspect of the anterior mandible which can be tied off or avoided. The superior/crestal part of the lingual flap lifts very easily, and if there are terminal branches of the lingual artery they will generally appear as little tissue tags a few mm inferiorly. Gently raise the flap around them and you will soon have sufficient exposure to tie them off with some 5.0 vycryl. The other thing about raising a lingual flap is that if by some chance you were to encounter a bleeder you could quickly tie it off with a big bite of tissue - something you won't be able to do in a hurry if you've gone in without raising a flap and gone off into tiger country. Don't get me wrong, I do advocate and practice flapless procedures elsewhere, but to me the safest way in the edentulous anterior mandible is by visualising and blunt probing the lingual plate. PS. I like using a curette as its small 'spoon' gives easy visualisation as to the depth of a lingual concavity as you slide the 'spoon' down and see how much of it drops out of view.

Nice post; good technique! Another way to acertain bone contours is with a tomogram of course. Some times I reduce the knife edge to gain a better platform; trying not to go completely through the cortex. American Dental Implant makes a 2.4 mm screw through implant with a 3.5 platform-Zimmer compatible along with many others, they also do a 3.3 with a 3.5 platform-both are aircraft grade Ti alloy. So both will accept locators.

I AM A MAC FACIAL WHO PRACTICES OUTSIDE OF THE USA AND AM GENERALLY VERY CRITICAL OF GP TYPE SURGEONS. I HAVE TO COMMENT THAT JOHN CLARK HAS A GOOD SOUND AND SAFE APPROACH. UNLESS YOU ABLE TO GET IN LINGUALLY; AVOID THE AREA;UNLESS YOU HAVE A COMPUTER GUIDED OPTION AVAILABLE. SADLY WHERE I WORK COMPUTER GUIDED AND GENERATED STENTS CAN BE PROHIBITIVELY EXPENSIVE NOT TO MENTION CT SCANS. A CHEAP AID THAT GIVES YOU A FEEL FOR THE MANDIBULAR WIDTH AND LINGUAL SHAPE IS THE LATERAL CEPH RADIOGRAPH. THIS TOGETHER WITH Dr CLARK TECHNIQUE WILL ALMOST ALWAYS BE A SAFE APPROACH. TO BEST OF MY KNOWLEDGE THREATENED AIRWAYS ONLY OCCUR WHEN YOU FAIL TO PROTECT LINGUALY AND THEN DISCHARGE THE PT. THE BLEED PICKS UP AS THE PATIENT STARTS TO MOVE AROUND AND THE LOCAL/VASOCONSTRICTOR WEARS OFF. IF YOU CAN CONFIRM NO ACTIVE BLEED BY VISUALIZATION BEFORE CLOSING THE TISSUES YOU WILL NOT BE IN LINE FOR TOO MUCH DRAMA. ALL THE FATAL OUTCOMES I AM AWARE OF SEEM TO BE RELATED TO LINGUAL MISADVENTURE IN THE PREMOLAR AREA. PAUL

First of all my salute to John Clark for being a very good GP surgeon. Only thing I would like to add for less experienced is,in case of unavailability of CT scan if lingual flap reflection is needed,than reflection should be done with finger and not sharp periosteal elevators. And one must be watchful for attachments at genial tubercle.

The anatomy you have seen is not only real, but is most often disregarded as artifact with potentially severe consequences. We have just published an article in the new journal Titanium on maxillofacial anatomy of the symphysis using CBCT imaging. There are several blood vessels and neurovascular bundles present intraforamenally. The first is the incisive canal. Rather than being the "anterior loop" of the mental foramen, it is actually an anstamosis of the IAN from mental foramen to mental foramen. It is the nerve and blood supply to the chin and anterior teeth. Anastamosing with the incisive canal are the lingual, sublingual, submental (branch of the facial artery), mylohyoid, and superior genial vessels. If you transect any of these, you may get a slight sensory deficit or, worse, a severe bleeding episode that can compromise the airway. There are several deaths and dozens of trips to the OR for tracheostomies noted in the literature. I recommend a CBCT scan for all surgeries in the symphysis, especially if the anterior segment is resorbed as you are closer to these anatomical structures. Guided surgery can help you navigate around them and avoid a potential disaster for you and your patient. DO NOT place implants directly in the midline. It has the highest incidence of morbidity of any intraoral site. Additionally, there can be profound variability of anatomy contralaterally within the same patient. RJM

Dear Dr. Miller, Would you be able to e-mail me that article after it is published, to me for teaching purpose? My e-mail address is 'sj18@nyu.edu'.

it looks like your planning to perforate the lingual cortex.the posts which concern about air way obestruction,means lingual cortex perforation where bleeding well find his way to soft tissue oral floor ( in this case pressure which be applied from out side the mouth with all the procedure which mentioned before rgarding the tongue raising & pt under obesrevation with no use of mouth wash) But I think it is all about directon of drilling that you should think about it. i think reflection of lingual flap is not needed ,there is no need to strip the bone that much.surgical stent should be used with caution cos it direct you only on the bone surface & while using it you have to remove it & check your orintation.if you talk about intrabony osteotomy so what you concern about in the area between the mental foramina is the nerve looping. A 3D mental visualization is important for any implant surgeon .

With respect to the anterior mental nerve loop Dr. Benninger at OHSU and Dr. Mohammad Sharawy at MCG, both friends of mine recently are reporting that the nerve loop may not exist. I know we all have seen it on Panoramic x-rays however, Dr. Benninger is about to publish a paper with a Scandanavian grooup showing same on a very large population of cadavers. You may want to contact him at OHSU in Portland, Oregon to discuss there findings. CT scan will keep you out of trouble both intraforaminally and with respect to the angle of the anterior mandible and sublingual undercuts/genial tubercles, extension of sublingual artery into the lingual aspect of the anterior mandible and so much more. If you haven't done numerous head and neck dissections recently and you are just beginnning your surgical implant career then seek expert guidance in the event of a mishap. You don't want to go into the surgery nervous or uncomfortable and without confidence and you sure don't want to drill just to drill. If you have a CT then please forward same for comments. We are all at different stages in our careers both professionally and personally and there is nothing wrong with seeking advice from those who routinely work in anatomical spaces that need to be protected. The good news is the anterior mandible is one of the safest areas to perform surgery, especially the recently edentulous cases. Please feel free to call me at 541-330-1400 if you would like to discuss case. Duke Aldridge, DDS, MAGD, MICOI Asst. Professor, OHSU

Dr. Miller, Could you please e-mail me the article that you are referring to so I can use it for reference and in teaching? Thank you in advance. Duke Aldridge

If you plan to insert implants mesially to foramen mentale, there is no need to refrain from anterior loop of nerve in edentulous patients. we know that anterior loop of nerve innervates incisor teeth.The best way to overcome complications like bleeding or nerve injury is not to harm these structures from beginning. for Perfect vision of bone angulation, reflect flap as possible as you can. It wont be easy to perforate lingual cortical bone if you work in low speed like 500-600 rpm with your drill. Just feel it. May the bone be with u.... Oral Ä°mplantolog

Why are we talking about lingual perf or lingual flap? Doctor is worried about large blood vessel inside mandible, not sublingual space. As mentioned by some one use of drills with stop should be answer. Also it will help to use tapering implant.

dr. dukes is right. to avoid these risks i learned among years to amplifay my fingers sensibility to recognice the dura-madre when i approach this lamina wherever is. Naturally i make this approach with a very fine drill (n° 40-50) at 1500-2000 turns pm.