 Hello everyone, welcome back to another session in dentistry and more Today we have the continuation of our maxillary nerve blocks. So last session was about intra-orbital nerve block So this session is posterior, superior, angular nerve block, but also known as PSA So we'll start with a nerve anatomy That is the tritaminal nerve which has got three parts of thalamic, maxillary and mandibular And this posterior superior alveolar nerve is a part of maxillary nerve So this is a maxillary nerve. So you can see all the branches. So last session we finished our intra-orbital nerve which has got terminal branches like inferior palpibril, lateral nasal and superior labial and You can see the anterior superior alveolar nerve, then the middle superior alveolar nerve And you can see the posterior superior alveolar nerve which is originating just below the intra-orbital Foramen. So when we apply intra-orbital nerve block it mostly Anesthetized this part that is palpibril. There is a terminal branches palpibril, nasal, labial Then the anterior superior alveolar nerve and middle superior alveolar nerve. Okay. So we have One, two, three, that is the central incisor canine and the lateral incisor which is supplied by anterior superior alveolar nerve whereas pre-molars 4-5 and the meso-buckle root of 6 supplied by middle superior alveolar nerve and The other molars that is 7 and 8 that is second molar and third molar also the roots which is accepted that is a disturb buckle and palatal root of 6 that is the first molar supplied by posterior superior alveolar nerve. Okay. So this is how The nerve supplies the teeth, pulp and pyridontium Central lateral canine is supplied by anterior superior alveolar nerve which is anterior most branch then the middle superior alveolar nerve which is supplying two premolars and the Meso-buckle which is near to the premolar Meso-buckle root of first molar the remaining That is second and third molar along with the other roots other than meso-buckle. That is a disturb buckle and palatal roots Moving on posterior superior alveolar nerve, which is a very commonly used nerve block technique for the Maxillary posterior teeth Commonly the second and third molars. The first molar Meso-buckle is supplied by the middle superior alveolar nerve So the disturb buckle and palatal side will be supplied by PSA. So around 20 to 30 percentage of cases The Meso-buckle root will not be anesthetized when we give PSA. So in those cases, we might need to give middle superior alveolar block separately. So That is about the nerve blocks posterior superior and the middle superior alveolar nerve The main thing is we need to visualize the skull size The skull size is a very important factor with respect to the depth of soft tissue penetration Okay So always when we give PSA we use shorter needles Because of this to avoid these kind of complications. So the average depth of soft tissue penetration is 16 mm So it can be used for the posterior superior alveolar nerve The 16 mm will be the ideal depth of penetration with respect to the PSA So it has got some other names such as Zygomatic block or the tuberosity block. It is being given in that area Zygomatic bone or maxillary tuberosity So the nerve anesthetized is the posterior superior alveolar nerve and its branches So the area anesthetized is mainly the parts of maxillary third and second molar and the first molar also But except the Meso-buckle root but only in around 20 to 30 percentage of the cases So that is the nerve and area anesthetized Now what are the indications? Indications as we discussed when the treatment involving two or more maxillary molars when supraperiosteal injection is contraindicated because of any infection or inflammation or the supraperiosteal injection is found to be ineffective in all those cases we can go for a PSA block Whereas it is contraindicated when the risk of hemorrhage is too great If the patient is hemophilic In which case we can go for a supraperiosteal injection or a periodontal ligament injection We should not go for a PSA nerve block in case of Hemophilic patients because high chances of Hemorrhage So in those cases we can give just a PDL injection or a periosteal supraperiosteal injection instead of a nerve block So what are the advantages though the foremost advantage is it's very traumatic And there is high success rate so advantage is just We are not getting any bony resistance. So it's just piercing through the soft tissue the patient also won't feel much pain So that is why it is a traumatic one of the most a traumatic injection then high success rate around 95 percentage and we need just one injection compared to three infiltrations and It minimizes the total volume of local anesthetic solution Administer because we are giving only once instead of three infiltrations But the disadvantages are Disadvantages Commonly reported problem associated with PSA and this technique is somewhat arbitrary and Sometimes second injection necessary for the treatment of the mesobuclute of maxillary first model in around 20 to 30 percentage cases But otherwise it is just one Uh Instruction is fine if it is second molar or third molar, but in case of first molar where the mesobuclute is involved We need to give a second injection now the technique technique of PSA that is 25 gauge Short needle is used in intra-orbital. We were using long needle This is short needle in order to avoid all the complications So insert needle at the height of muco buckle fold muco buckle fold above the maxillary Second molar as you see the picture here muco buckle fold of maxillary second molar So the target area is the PSA nerve which is posterior superior and medial to the posterior border of the Maxilla posterior superior and medial to the posterior border of maxilla posterior border of maxilla. So this is the target area where the PSA Now lies So the landmarks of the muco buckle fold maxillary tuberosity and zygomatic process of maxilla They are the landmarks. Okay, so landmarks are muco buckle fold maxillary tuberosity and zygomatic process of maxilla And we should have the patient open their mouth only halfway not completely Because it creates more room for the injection Then to track the patient's cheek width mirror pull the tissues at the injection site very taut Then Orient the bevel towards the bone insert the needle at height of the muco buckle fold over the second maxillary molar advance the needle Upward inward and backward. Okay inward backward direction so patient or the Dentist might not feel the resistance And penetrating to an average depth of 16 millimeter is adequate and Aspirate in two planes by rotating the bevel one quarter turn. Okay one quarter turn We need to rotate and aspirate in two planes and Deposit around one two one point five mill of solution and wait for three to five minutes So always we need to be careful that we need to advance the needle in one moment Okay, not three separate moments. Just one moment. We need to make all the directions not Three separate moments We should not create because it will create a traumatic feeling because usually this is very a traumatic So that we need to be careful only one moment for the Injection not three separate moments. Okay That is we are going to do a upward inward and backward direction So that should be done in a one moment and for left PSA the dentist should be at 10 o'clock position and for the right PSA Dentist should be at 8 o'clock position So the science and symptoms subject to science there will be Absence of pain there will not be much subject to symptoms because Patients will not be having any sensation on the Bacalmucosa or lip. So the lack of pain during instrumentation can be an indication for the LA effectiveness So also we can use in electric pulp testing Unlike other Now blocks because in any other nerve blocks such as the intra orbital IA and we all know blocks gives very subjective symptoms to use symptoms that is Patient gives you some clue About the LA effectiveness. Patience is the numbness tingling of leap in PSA the subjective symptoms are very Minimal so the dentist can do instrumentation and make sure that the LA has Worked out or we can use a electric pulp testing to check the LA effectiveness So the safety features we should give slow injection and there is no anatomic safety Features to prevent over insertion of the needle. So we need to be very careful about the length of the needle Okay, slow injection slow injection and length So the dentist should be careful about the length because there is no anatomic landmarks So the depth of the needle penetration should be correct over insertion increases the risk of hematoma and too shallow might still provide adequate anesthesia so always be very careful about the over insertion So what are the reasons for failure of anesthesia one thing is needle is too lateral So we need to redirect the tip medially when it is going to lateral or the needle is too posterior true posterior We can withdraw the needle to the proper depth or needle Not high enough. So we can also redirect the needle tip superiorly So it should be medial superior and posterior But it should be at a proper direction should not be too lateral should not be too posterior and should not be Needle not high enough Now the complications That is very important in PSA very commonly asked question. What are the complications? We already discussed a bit One thing is the hematoma This is a commonly produced by inserting the needle too far posteriorly into the pterigoid plexus of veins So there is presence of pterigoid plexus Pterigoid plexus of veins if you miss out this point We won't get any marks So never miss this point pterigoid plexus open that is present Posteriorly, okay, and we are going too far posteriorly We are going to insert the solution into this spot. That is a pterigoid plexus of veins. It creates Hematoma and also there are problems of Mantibular anesthesia since we are giving maxillary anesthesia should not create Unnecessary mantibular anesthesia Why this is happening because the mantibular division of the fifth cranial nerve, okay That is a tricheminal nerve is located lateral to this PSA. It is located lateral to this PSA So if you are giving LA lateral to the desired location, what happens is is going to deposit solution on the Mantibular division of the cranial nerve, okay instead of Maxillary we are going to anesthetize mantibular nerve because we are giving to laterally So that is the second problem first one is Hematoma that the mantibular anesthesia. The next thing is Diplopia That is the double vision Diplopia how this Diplopia is happening So when we are giving PSA When they are being deposited near the pterigo maxillary fissure, okay pterigo Maxillary fissure they are the areas or they are the Structures or the fissure which is present near the PSA Just like our pterigoid plexus of veins So when we are depositing the solution near the pterigoid maxillary fissure It causes Diplopia of the Ypsilatrile or the left or right wherever the instruction is being done Diplopia will result not in all cases some around 30 to 40 percentage of the cases This is because the local anesthesia diffusing superiorly and medially to Anesthetize the orbital nerves It will affect the orbital nerves It is only affecting Ypsilatrile not bilateral only on the Injection site, okay, so this is going to affect the orbital nerve Next one is a facial nerve facial nerve Paralysis So facial nerve paralysis it's because this local anesthetic Interaction is going into the posterior superior alveolar R3 So when it is being injected into this R3 and it is going subsequently to The pitrosal R3 branches and finally it creates facial nerve palsy for some authors says that The improper placement of the needle could lead to the damage of pterigoid plexus So this local anesthetic will reach the inferior portion of the parotid gland which anesthetize the cervical facial division of the facial nerve or medial pterigoid muscles which would result in Trismus So PSA has many side effects or complications such as hematoma mandibular anesthesia Diplopia facial nerve paralysis and Trismus So you need to explain how it is happening in the moment it is associated with plexus of veins Mandibular anesthesia because when it is being injected lateral with this mandibular nerve and Diplopia it is associated with pterigo maxillary fissure and orbital nerves and facial nerve Paralysis it is associated with Either sometimes it could be the medial menageal R3 and pitrosal R3 pitrosal R3 branches to the facial nerve Injury or it could be due to the the solution being Placed through pterigoid plexus into the parotid gland inferior portion of the parotid gland where the cervical facial division of the facial nerve is there That is how it is creating a facial nerve paralysis and it is affecting the pterigoid muscles that is a medial pterigoid It results in Trismus So it is very commonly asked a secretion and there will be definitely an associated Complication part regarding them. So this is the nerve block which is associated with most number of complications So that was all about PSA. So PSA Just like any nerve block When you're writing for exam need to write about the landmarks now anesthetized the area anesthetized indications contraindication its advantages disadvantages and a little bit about its Beginning part that is a maxillary. It is coming from the trigeminal nerve and all those things along with The complications. Okay, why it is being failure and also the technique. Okay? So this is the most important part in posterior superior. So I'll come up with a new topic in oral surgery. Thank you