Sinus Maxillofacial CT - CAM 746

GENERAL INFORMATION

  • It is an expectation that all patients receive care/services from a licensed clinician. All appropriate supporting documentation, including recent pertinent office visit notes, laboratory data, and results of any special testing must be provided. If applicable: All prior relevant imaging results and the reason that alternative imaging cannot be performed must be included in the documentation submitted.
  • Where a specific clinical indication is not directly addressed in this guideline, medical necessity determination will be made based on widely accepted standard of care criteria. These criteria are supported by evidence-based or peer-reviewed sources such as medical literature, societal guidelines and state/national recommendations.

Policy 
A single authorization for CPT codes 70486, 70487, 70488, or 76380 includes imaging of the entire maxillofacial area, including face and sinuses. Multiple authorizations are not required.

INDICATIONS FOR SINUS & MAXILLOFACIAL CT

Rhinosinusitis1-5

  • Clinical suspicion of fungal infection6, 7
  • Clinical suspicion of complications,8 such as
    • Preseptal, orbital, or intracranial infection9
    • Osteomyelitis
    • Cavernous sinus thrombosis
  • Acute (< 4 weeks) or subacute (4-12 weeks) sinusitis (presumed infectious)
    • Not responding to medical management including 2 or more courses of antibiotics in the past 3 months
  • Recurrent acute rhinosinusitis with 4 or more annual episodes without persistent symptoms in-between
  • Chronic recurrent sinusitis3 (> 12 weeks)
    • Not responding to medical management*, and with at least two of the following:
      • mucopurulent discharge
      • nasal obstruction and congestion
      • facial pain, pressure, and fullness
      • decreased or absent sense of smell
    • With nasal polyps especially unilateral polyps, concern for polyps extending outside of the nasal cavity, or other atypical presentations3

*Note: Medical management for chronic sinusitis includes nasal saline irrigation and/or topical intranasal steroids. In chronic sinusitis, repeat imaging is not necessary unless clinical signs or symptoms have changed. Biologics such as dupilumab can be used to treat chronic sinusitis with nasal polyposis

  • Allergic Rhinitis – sinus imaging usually not indicated unless there are signs of complicated infection, signs of neoplasm, or persistence of symptoms/chronic rhinosinusitis despite treatment (including antihistamines) and is a possible surgical candidate10
  • If suspected as a cause of poorly controlled asthma (endoscopic sinus surgery improves outcomes)11
  • To evaluate in the setting of unilateral nasal polyps or obstruction3

Note: Imaging may be indicated in those predisposed to complications, including diabetes, immune-compromised state, immotile cilia disorders, or a history of facial trauma or surgery.

Pediatrics Rhinosinusitis12, 13

  • Persistent or recurrent sinusitis not responding to treatment (primarily antibiotics, treatment may require a change of antibiotics)
  • Suspicion of orbital or central nervous system involvement (e.g., swollen eye, proptosis, altered consciousness, seizures, nerve deficit)
  • Clinical suspicion of a fungal infection (more common in immunocompromised children)

Deviated nasal septum, polyp, or other structural abnormality seen on imaging or direct visualization

  • Causing significant airway obstruction AND
  • Imaging is needed to plan surgery or determine if surgery is appropriate14, 15

Suspected sinonasal mass based on exam, nasal endoscopy, or prior imaging 3, 16

Refractory Asthma - these patients benefit from medical treatment and surgery together11, 17, 18

Anosmia or Dysosmia noted on objective testing, is persistent, of unknown origin for evaluation of peripheral sinonasal disease and/or bone-related pathology.16,19-21

Suspected infection

  • Osteomyelitis (after x-rays and MRI cannot be performed)22
  • Abscess based on clinical signs and symptoms of infection

Face mass16, 23

  • Present on physical exam and remains non-diagnostic after x-ray or ultrasound is completed; OR
  • Known or highly suspected head and neck cancer on examination; OR
  • Failed 2 weeks of treatment for suspected infectious adenopathy24

Facial trauma25-33

  • Serious facial injury with concern for fracture on exam (e.g., bony step off, ecchymosis, nasal deformity, depression, malocclusion)

Note: x-rays should be performed for isolated dental/mandibular injury

  • Suspected facial bone fracture with indeterminate x-ray
  • For further evaluation of a known fracture for treatment or surgical planning

CSF (cerebrospinal fluid) rhinorrhea when looking to characterize a bony defect

Note: For intermittent leaks and complex cases, consider CT/MRI/Nuclear Cisternography. There should be a high suspicion or confirmatory CSF fluid laboratory testing (Beta-2 transferrin assay)

Salivary gland

  • Sialadenitis (infection and inflammation of the salivary glands) with indeterminate ultrasound, bilateral symptoms or concern for abscess34
  • Suspected or known salivary gland stones35-37

Granulomatosis with polyangiitis (Wegener’s granulomatosis) disease38

Suspected Osteonecrosis of the Jaw39

  • Possible etiologies: bisphosphonate treatment, dental procedures, Denosumab, radiation treatment

Trigeminal neuralgia/neuropathy if MRI is contraindicated or cannot be performed (for evaluation of the extracranial nerve course)

  • If atypical features (i.e., bilateral, hearing loss, dizziness/vertigo, visual changes, sensory loss, numbness, pain > 2min, pain outside trigeminal nerve distribution, progression)6, 40

Pre-operative/procedural evaluation

  • Pre-operative evaluation for a planned surgery or procedure

Post-operative/procedural evaluation

  • When imaging, physical, or laboratory findings indicate surgical or procedural complications

Further evaluation of indeterminate findings on prior imaging (unless follow up is otherwise specified within the guideline):

  • For initial evaluation of an inconclusive finding on a prior imaging report that requires further clarification.37
  • One follow-up exam of a prior indeterminate MR/CT finding to ensure no suspicious interval change has occurred. (No further surveillance unless specified as highly suspicious or change was found on last follow-up exam)

Cone Beam CT (CBCT)

  • Can be used in the evaluation of rhinosinusitis for the above-mentioned indications and for surgical planning/pre-operative evaluation in non-neoplastic indications.

* Cone beam CT is not approvable in the evaluation of dentomaxillofacial imaging16, 41-44

COMBINATION OF STUDIES WITH SINUS & MAXILLOFACIAL CT

Sinus CT/Chest CT

  • Granulomatosis with polyangiitis (Wegener’s granulomatosis) disease (GPA)45

Sinus CT/Chest CT/Abdomen and Pelvis CT/Brain MRI46, 47

  • For initial workup prior to Bone Marrow Transplant (BMT)

Rationale
Computed tomography (CT) primarily provides information about bony structures but may also be useful in evaluating soft tissue masses. It can help document the extent of facial bone fractures, facial infections, and abscesses, and can aid in diagnosing salivary stones. Additionally, CT may be useful in characterizing and identifying tumor extent in the face and may be used in the assessment of chronic osteomyelitis.

CT scans can provide more detailed information about the anatomy and abnormalities of the paranasal sinuses than plain films. A CT scan provides greater definition of the sinuses and is more sensitive than plain radiography for detecting sinus pathology, especially within the sphenoid and ethmoid sinuses. CT scan findings can be nonspecific, however, and should not be used routinely in the diagnosis of acute sinusitis. The primary role of CT scans is to aid in the diagnosis and management of recurrent and chronic sinusitis, or to define the anatomy of the sinuses prior to surgery.

CT vs MRI - MRI allows better differentiation of soft tissue structures within the sinuses. It is used occasionally in cases of suspected tumors or fungal sinusitis. Otherwise, MRI has no advantages over CT scanning in the evaluation of sinusitis. Disadvantages of MRI include high false-positive findings, poor bony imaging, and higher cost. MRI scans take considerably longer to accomplish than CT scans and may be difficult to obtain in patients who are claustrophobic.

Rhinosinusitis - Society consensus recommendation is not to order sinus computed tomography (CT) or indiscriminately prescribe antibiotics for uncomplicated acute rhinosinusitis.42 Viral infections cause the majority of acute rhinosinusitis and only 0.5 percent to 2 percent progress to bacterial infections. Most acute rhinosinusitis resolves without treatment in two weeks. Uncomplicated acute rhinosinusitis is generally diagnosed clinically and does not require a sinus CT scan or other imaging. Antibiotics are not recommended for patients with uncomplicated acute rhinosinusitis who have mild illness and assurance of follow-up. If a decision is made to treat, amoxicillin with clavulanate should be first-line antibiotic treatment for most acute rhinosinusitis. If improvement is not demonstrated, it is recommended to change antibiotics to either high-dose amoxicillin plus clavulanate, doxycycline, a fluoroquinolone such as moxifloxacin or levofloxacin, or a dual treatment of clindamycin plus a third-generation oral cephalosporin.5

Anosmia - Nonstructural causes of anosmia include post viral symptoms, medications (Amitriptyline, Enalapril, Nifedipine, Propranolol, Penicillamine, Sumatriptan, Cisplatin, Trifluoperazine, Propylthiouracil). These should be considered prior to advanced imaging to look for a structural cause. Anosmia and dysgeusia have been reported as common early symptoms in patients with COVID-19, occurring in greater than 80 percent of patients. For isolated anosmia, imaging is typically not needed once the diagnosis of COVID has been made, given the high association. As such, COVID testing should be done prior to imaging.48-50 MRI Orbits, Face, and Neck MRI rather than MRI Brain is the mainstay for directly imaging the olfactory apparatus and sinonasal or anterior cranial fossa tumors that may impair or directly involve the olfactory apparatus.6

Suspected Osteonecrosis of the Jaw - CT scan characterize the extension of the lesions and in detecting cortical involvement. MRI should be reserved for those patients who have soft tissue extension of the disease.51

Trigeminal Neuralgia - According to the International Headache Society, TN is defined as “a disorder characterized by recurrent unilateral brief electric shock-like pain, abrupt in onset and termination, limited to the distribution of one or more divisions of the trigeminal nerve and triggered by innocuous stimuli.”52

References

  1. Chiarella SE, Grammer LC. Immune deficiency in chronic rhinosinusitis: screening and treatment. Expert Rev Clin Immunol. Feb 2017;13(2):117-123. doi:10.1080/1744666x.2016.1216790
  2. Kaplan A. Canadian guidelines for chronic rhinosinusitis: Clinical summary. Can Fam Physician. 2013;59(12):1275-e534.
  3. Rosenfeld RM, Piccirillo JF, Chandrasekhar SS, et al. Clinical practice guideline (update): adult sinusitis. Otolaryngol Head Neck Surg. Apr 2015;152(2 Suppl):S1-s39. doi:10.1177/0194599815572097
  4. Brook I, Hinthorn DR. Chronic sinusitis questions & answers. WebMD, LLC. Updated July 1, 2019. Accessed December 30, 2022. https://emedicine.medscape.com/article/232791-questions-and-answers
  5. Frerichs N, Brateanu A. Rhinosinusitis and the role of imaging. Cleve Clin J Med. Jul 31 2020;87(8):485-492. doi:10.3949/ccjm.87a.19092
  6. American College of Radiology. ACR Appropriateness Criteria® Cranial Neuropathy. American College of Radiology (ACR). Updated 2022. Accessed January 22, 2023. https://acsearch.acr.org/docs/69509/Narrative/
  7. Silveira MLC, Anselmo-Lima WT, Faria FM, et al. Impact of early detection of acute invasive fungal rhinosinusitis in immunocompromised patients. BMC Infect Dis. Apr 5 2019;19(1):310. doi:10.1186/s12879-019-3938-y
  8. Dankbaar JW, van Bemmel AJ, Pameijer FA. Imaging findings of the orbital and intracranial complications of acute bacterial rhinosinusitis. Insights Imaging. Oct 2015;6(5):509-18. doi:10.1007/s13244-015-0424-y
  9. Kastner J, Simmen D, Netuka D, Kastner J, Gudziol V. Orbital and Intracranial Complications of Acute and Chronic Rhinosinusitis. In: Chang CC, Incaudo GA, Gershwin ME, eds. Diseases of the Sinuses: A Comprehensive Textbook of Diagnosis and Treatment. Springer New York; 2014:495-515.
  10. Seidman MD, Gurgel RK, Lin SY, et al. Clinical Practice Guideline: Allergic Rhinitis. Otolaryngol Head Neck Surg. 2015/02/01 2015;152(1_suppl):S1-S43. doi:10.1177/0194599814561600
  11. Vashishta R, Soler ZM, Nguyen SA, Schlosser RJ. A systematic review and meta-analysis of asthma outcomes following endoscopic sinus surgery for chronic rhinosinusitis. Int Forum Allergy Rhinol. Oct 2013;3(10):788-94. doi:10.1002/alr.21182
  12. American College of Radiology. ACR Appropriateness Criteria® Sinusitis--Child. American College of Radiology. Updated 2018. Accessed December 30, 2022. https://acsearch.acr.org/docs/69442/Narrative/
  13. Wald ER, Applegate KE, Bordley C, et al. Clinical practice guideline for the diagnosis and management of acute bacterial sinusitis in children aged 1 to 18 years. Pediatrics. Jul 2013;132(1):e262-80. doi:10.1542/peds.2013-1071
  14. Poorey VK, Gupta N. Endoscopic and computed tomographic evaluation of influence of nasal septal deviation on lateral wall of nose and its relation to sinus diseases. Indian J Otolaryngol Head Neck Surg. Sep 2014;66(3):330-5. doi:10.1007/s12070-014-0726-2
  15. Sedaghat AR, Kieff DA, Bergmark RW, Cunnane ME, Busaba NY. Radiographic evaluation of nasal septal deviation from computed tomography correlates poorly with physical exam findings. Int Forum Allergy Rhinol. Mar 2015;5(3):258-62. doi:10.1002/alr.21445
  16. American College of Radiology. ACR Appropriateness Criteria® Sinonasal Disease. American College of Radiology (ACR). Updated 2021. Accessed December 30, 2022. https://acsearch.acr.org/docs/69502/Narrative/
  17. Sahay S, Gera K, Bhargava SK, Shah A. Occurrence and impact of sinusitis in patients with asthma and/or allergic rhinitis. J Asthma. Aug 2016;53(6):635-43. doi:10.3109/02770903.2015.1091005
  18. Ragab S, Scadding GK, Lund VJ, Saleh H. Treatment of chronic rhinosinusitis and its effects on asthma. Eur Respir J. Jul 2006;28(1):68-74. doi:10.1183/09031936.06.00043305
  19. Lie G, Wilson A, Campion T, Adams A. What's that smell? A pictorial review of the olfactory pathways and imaging assessment of the myriad pathologies that can affect them. Insights Imaging. Jan 7 2021;12(1):7. doi:10.1186/s13244-020-00951-x
  20. Kandemirli SG, Altundag A, Yildirim D, Tekcan Sanli DE, Saatci O. Olfactory Bulb MRI and Paranasal Sinus CT Findings in Persistent COVID-19 Anosmia. Acad Radiol. Jan 2021;28(1):28-35. doi:10.1016/j.acra.2020.10.006
  21. Li C, Yousem DM, Doty RL, Kennedy DW. Neuroimaging in patients with olfactory dysfunction. AJR Am J Roentgenol. Feb 1994;162(2):411-8. doi:10.2214/ajr.162.2.8310937
  22. Pincus DJ, Armstrong MB, Thaller SR. Osteomyelitis of the craniofacial skeleton. Semin Plast Surg. 2009;23(2):73-79. doi:10.1055/s-0029-1214159
  23. Koeller KK. Radiologic Features of Sinonasal Tumors. Head Neck Pathol. Mar 2016;10(1):1-12. doi:10.1007/s12105-016-0686-9
  24. Haynes J, Arnold KR, Aguirre-Oskins C, Chandra S. Evaluation of neck masses in adults. Am Fam Physician. May 15 2015;91(10):698-706.
  25. American Medical Society for Sports Medicine (AMSSM). Choosing Wisely: Avoid Performing Plain X-Rays in Instances of Facial Trauma. Accessed March 21, 2023. https://www.sportsmedtoday.com/choosing-wisely:-avoid-performing-plain-xrays-in-instances-of-facial-trauma-va-129.htm
  26. Sun JK, LeMay DR. Imaging of facial trauma. Neuroimaging Clin N Am. May 2002;12(2):295-309. doi:10.1016/s1052-5149(02)00002-3
  27. American Academy of Family Physicians. Avoid performing plain x-rays in instances of facial trauma. Choosing Wisely Initiative ABIM Foundation. Accessed March 21, 2023. https://www.aafp.org/pubs/afp/collections/choosing-wisely/205.html
  28. Echo A, Troy JS, Hollier LH, Jr. Frontal sinus fractures. Semin Plast Surg. 2010;24(4):375-382. doi:10.1055/s-0030-1269766
  29. American College of Radiology. ACR Appropriateness Criteria® Head Trauma. American College of Radiology (ACR). Updated 2020. Accessed January 29, 2023. https://acsearch.acr.org/docs/69481/Narrative/
  30. American College of Radiology. ACR Appropriateness Criteria® Major Blunt Trauma. American College of Radiology. Updated 2019. Accessed December 30, 2022. https://acsearch.acr.org/docs/3102405/Narrative/
  31. Oh JW, Kim SH, Whang K. Traumatic Cerebrospinal Fluid Leak: Diagnosis and Management. Korean J Neurotrauma. Oct 2017;13(2):63-67. doi:10.13004/kjnt.2017.13.2.63
  32. Raju N, Ishwar P, Banerjee R. Role of multislice computed tomography and three-dimensional rendering in the evaluation of maxillofacial injuries. Original Article. Journal of Oral and Maxillofacial Radiology. September 1, 2017 2017;5(3):67-73. doi:10.4103/jomr.jomr_25_17
  33. Vemuri NV, Karanam LSP, Manchikanti V, Dandamudi S, Puvvada SK, Vemuri VK. Imaging review of cerebrospinal fluid leaks. Indian J Radiol Imaging. Oct-Dec 2017;27(4):441-446. doi:10.4103/ijri.IJRI_380_16
  34. Abdel Razek AAK, Mukherji S. Imaging of sialadenitis. Neuroradiol J. Jun 2017;30(3):205-215. doi:10.1177/1971400916682752
  35. Gadodia A, Bhalla AS, Sharma R, Thakar A, Parshad R. Bilateral parotid swelling: a radiological review. Dentomaxillofac Radiol. 2011;40(7):403-414. doi:10.1259/dmfr/17889378
  36. Kalia V, Kalra G, Kaur S, Kapoor R. CT Scan as an Essential Tool in Diagnosis of Non-radiopaque Sialoliths. J Maxillofac Oral Surg. Mar 2015;14(Suppl 1):240-4. doi:10.1007/s12663-012-0461-8
  37. Terraz S, Poletti PA, Dulguerov P, et al. How reliable is sonography in the assessment of sialolithiasis? AJR Am J Roentgenol. Jul 2013;201(1):W104-9. doi:10.2214/ajr.12.9383
  38. Pakalniskis MG, Berg AD, Policeni BA, et al. The Many Faces of Granulomatosis With Polyangiitis: A Review of the Head and Neck Imaging Manifestations. AJR Am J Roentgenol. Dec 2015;205(6):W619-29. doi:10.2214/ajr.14.13864
  39. Popovic KS, Kocar M. Imaging findings in bisphosphonate-induced osteonecrosis of the jaws. Radiol Oncol. Dec 2010;44(4):215-9. doi:10.2478/v10019-010-0032-x
  40. Borges A, Casselman J. Imaging the trigeminal nerve. Eur J Radiol. May 2010;74(2):323-40. doi:10.1016/j.ejrad.2010.02.006
  41. Han M, Kim HJ, Choi JW, Park DY, Han JG. Diagnostic usefulness of cone-beam computed tomography versus multi-detector computed tomography for sinonasal structure evaluation. Laryngoscope Investig Otolaryngol. Jun 2022;7(3):662-670. doi:10.1002/lio2.792
  42. Bozdemir E, Gormez O, Yıldırım D, Aydogmus Erik A. Paranasal sinus pathoses on cone beam computed tomography. J Istanb Univ Fac Dent. 2016;50(1):27-34. doi:10.17096/jiufd.47796
  43. American Academy of Otolaryngology - Head and Neck Surgery. Position Statement: Point-of-Care Imaging in Otolaryngology. Updated April 21, 2021. Accessed March 21, 2023. https://www.entnet.org/resource/position-statement-point-of-care-imaging-in-otolaryngology/
  44. Al Abduwani J, ZilinSkiene L, Colley S, Ahmed S. Cone beam CT paranasal sinuses versus standard multidetector and low dose multidetector CT studies. Am J Otolaryngol. Jan-Feb 2016;37(1):59-64. doi:10.1016/j.amjoto.2015.08.002
  45. Lohrmann C, Uhl M, Warnatz K, Kotter E, Ghanem N, Langer M. Sinonasal computed tomography in patients with Wegener's granulomatosis. J Comput Assist Tomogr. Jan-Feb 2006;30(1):122-5. doi:10.1097/01.rct.0000191134.67674.c6
  46. Gerull S, Medinger M, Heim D, Passweg J, Stern M. Evaluation of the Pretransplantation Workup before Allogeneic Transplantation. Biology of Blood and Marrow Transplantation. 2014/11/01/ 2014;20(11):1852-1856. doi:https://doi.org/10.1016/j.bbmt.2014.06.029
  47. Kaste SC, Kaufman RA, Sunkara A, et al. Routine pre- and post-hematopoietic stem cell transplant computed tomography of the abdomen for detecting invasive fungal infection has limited value. Biol Blood Marrow Transplant. Jun 2015;21(6):1132-5. doi:10.1016/j.bbmt.2015.02.023
  48. Geyer M, Nilssen E. Evidence-based management of a patient with anosmia. Clin Otolaryngol. Oct 2008;33(5):466-9. doi:10.1111/j.1749-4486.2008.01819.x
  49. Lechien JR, Chiesa-Estomba CM, De Siati DR, et al. Olfactory and gustatory dysfunctions as a clinical presentation of mild-to-moderate forms of the coronavirus disease (COVID-19): a multicenter European study. Eur Arch Otorhinolaryngol. Aug 2020;277(8):2251-2261. doi:10.1007/s00405-020-05965-1
  50. Saniasiaya J, Islam MA, Abdullah B. Prevalence of Olfactory Dysfunction in Coronavirus Disease 2019 (COVID-19): A Meta-analysis of 27,492 Patients. Laryngoscope. Apr 2021;131(4):865-878. doi:10.1002/lary.29286
  51. Phal PM, Myall RW, Assael LA, Weissman JL. Imaging findings of bisphosphonate-associated osteonecrosis of the jaws. AJNR Am J Neuroradiol. Jun-Jul 2007;28(6):1139-45. doi:10.3174/ajnr.A0518
  52. Headache Classification Committee of the International Headache Society (IHS) The International Classification of Headache Disorders, 3rd edition. Cephalalgia. Jan 2018;38(1):1-211. doi:10.1177/0333102417738202

ADDITIONAL RESOURCES

  1. Mantur M, Łukaszewicz-Zając M, Mroczko B, et al. Cerebrospinal fluid leakage--reliable diagnostic methods. Clin Chim Acta. May 12 2011;412(11-12):837-40. doi:10.1016/j.cca.2011.02.017
  2. Moeller CW, Martin J, Welch KC. Sinonasal evaluation preceding hematopoietic transplantation. Otolaryngol Head Neck Surg. May 2011;144(5):796-801. doi:10.1177/0194599810395089

Coding Section 

Code Number Description
CPT 70486 Computed tomography, maxillofacial area; without contrast material
  70487 Computed tomography, maxillofacial area; with contrast material(s)
  70488 Computed tomography, maxillofacial area; without contrast material, followed by contrast material(s) and further sections
  76380 Computed tomography, limited or localized follow-up study

Procedure and diagnosis codes on Medical Policy documents are included only as a general reference tool for each Policy. They may not be all-inclusive

This medical policy was developed through consideration of peer-reviewed medical literature generally recognized by the relevant medical community, U.S. FDA approval status, nationally accepted standards of medical practice and accepted standards of medical practice in this community, Blue Cross Blue Shield Association technology assessment program (TEC) and other non-affiliated technology evaluation centers, reference to federal regulations, other plan medical policies, and accredited national guidelines.

"Current Procedural Terminology © American Medical Association. All Rights Reserved" 

History From 2019 Forward     

12/01/2023 Annual review, entire policy updated for consistency. Updated policy verbiage for nasal polyps, cone beam CT, CSF rhinorrhea, biologics like dupilumab. Numerous clarifications in policy that do not change intent.
12/16/2022 Annual review, no change o policy intent. Policy updated for clarity and specificity.)

12/08/2021 

Annual review, multple additions and clarifications in policy verbiage related to chronic recurrent sinusitis, facial trauma, sinonasal bone mass, dysosmia, sialadenitis, rhinosinusitis, and csf rhinorrhea. Also updating description and references. 

12/01/2020 

Annual review, revising policy verbiage for multiple issues including pediatric rhinosinusitis, jaw osteonecrosis, trigeminal neuralgia and visualized lesions. Also updating background and references. 

12/03/2019

New Policy

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