Добавил:
Sekretar
kiopkiopkiop18@yandex.ru
t.me/Prokururor I Вовсе не секретарь, но почту проверяю
Опубликованный материал нарушает ваши авторские права? Сообщите нам.
Вуз:
Предмет:
Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_892_Библиотеки_им_академика_М_И_Перельмана
.pdf
182
https://t.me/medicina_free
A. Beech and J. Moe
ih
Fig. 9.11 (continued)
alterations in blood ow, potentially predisposing toward postoperative ap failure [52].
ICGA has variable value in perforator assessment. A retrospective comparative
study of 28 patients who had undergone ALT ap found that ICGA was reliable in
intraoperatively identifying the dominant perforator and found the use of ICGA
resulted in a decrease in operator time and an increase in distal ap survival [53]. A
prospective study of 12 patients undergoing ALT perforator ap found that in comparison to handheld Doppler CDU, ICGA was superior in identifying perforator
anatomy with 100% sensitivity and 100% PPV [54]. Conversely, a study of 50
patients undergoing free ap reconstruction found the PPV and sensitivity of ICGA,
multidetector-row computed tomography (MDCT), and Doppler owmetry were
84% and 76%, 100% and 70%, and 80% and 100%, respectively, in the preoperative
evaluation of ap perforator anatomy [55]. In this study, MDCT was less accurate
in aps with a thickness less than 8mm, and ICGA was less reliable in aps with a
thickness greater than 20mm, suggesting the mode of examination should be determined based on the characteristics of the ap [55].
ICGA is likely better utilized to assess ap perfusion than mapping perforators.
Limitations of ICGA include providing information on arterial perfusion limited to
a depth less than 1cm, issues with both underestimation and overestimation of perfusion, and being subject to dynamic changes affected by patient temperature, cardiac
output, volume status, blood pressure, volume support, and the local microvascular
environment [47]. Additionally, protocols for optimal dosing and timing of contrast
administration are not standardized. As such, ICGA should be considered as an
adjunct tool to be used in combination with additional examination modalities.
9 Trends inMicrovascular Surgery
https://t.me/medicina_free
183
Postoperative Flap Monitoring
The greatest risk to free ap vitality is a thrombotic occlusion of the vein or artery.
Over 95% of these events occur within the rst 72h postoperatively. Early detection
of pedicle thrombosis is essential for successful thrombectomy and salvage. The
gold standard for free ap monitoring remains frequent intermittent clinical examination and is associated with low false-negative and low false-positive rates. Clinical
examination includes an assessment of ap color, capillary rell, warmth, turgor,
and bleeding on pinprick (Fig. 9.12). However, clinical monitoring can be labor
intensive and subjective, dependent on the experience of the examiner. Additionally,
clinical exam alone has a low salvage rate of approximately 63%, potentially as a
result of subclinical changes in ap perfusion occurring signicantly earlier than
clinically evident manifestations of congestion or ischemia [56].
External handheld Doppler systems can supplement the clinical examination and
are effective when assessing changes in arterial patency but are less sensitive when
assessing venous ow. These devices are useful in monitoring an external skin paddle but less helpful for buried aps. Additionally, reliance on external Doppler signal can delay identication of venous insufciency, as the arterial signal can be
present in the setting of completed venous occlusion for up to 6h.The use of the
implantable venous Doppler is now widely used for postoperative ap monitoring.
Additional postoperative monitoring methods include tissue spectroscopy, intravenous uorescein, thermography, transcutaneous laser Doppler, photoplethysmography, and transcutaneous PO2 monitoring.
ab
Fig. 9.12 (a) Clinical signs of a viable ap. (b) Clinical signs of venous congestion
184
https://t.me/medicina_free
A. Beech and J. Moe
Implantable Doppler Probe Systems
In response to challenges in monitoring buried and intraoral free aps, Hartley and
Cole described the 20-MHz unidirectional ultrasound Doppler probe in 1974 [57].
In 1988, Swartz etal. described a 1.0mm Doppler probe with a 20Hz ultrasonic
probe applied to a silicone cuff which could be wrapped around the vessel of interest [58]. This allowed for continuous, real-time monitoring of vessel blood ow
through both audible and visual monitor display. More recently, Doppler probes
integral to the anastomotic coupler system have been developed [59], avoiding the
additional step of applying the separate monitoring cuff around the anastomosis and
improving operating time.
Multiple studies have shown improved detection of ischemia when using the
implantable Doppler probe, particularly when monitoring buried aps. A retrospective study comparing 259 microvascular free aps monitored with implantable
Doppler and 289 aps monitored by clinical means across a wide spectrum of surgical subspecialties found improved overall success rates in the implantable Doppler
group (96% vs. 89%) with the greatest benet of the device seen in head and neck
procedures (95% vs. 84%) and improved salvage rates in the implantable Doppler
group (95% vs. 40%) [60]. A study of 1142 free aps for head and neck reconstruction using the implantable Doppler reported a 12% detection rate of incipient failures in the operating room leading to immediate revision prior to closure and
reported an overall ap survival rate of 98% [61]. While the implantable Doppler
has a high sensitivity (87% to 100%) and specicity (99%) for detecting loss of ap
perfusion, it suffers from a variable false positive rate (<1% to 88%), which potentially leads to a high proportion of subsequent negative surgical explorations [62,
63]. Corroboration with clinical exam and the use of a second assessment tool such
as color duplex sonography to conrm the implantable Doppler ndings has been
described [63].
Arterial vessel monitoring has been described with fewer false-positive results
but with greater false-negative rates, and both arterial and venous monitoring are
routinely done postoperatively based on surgeon preference [64]. A systematic
review of 763 aps with implantable Doppler probes on 527 arteries and 388 veins
found a 74% reduction in risk of false positives and 63% reduction in risk of signal
loss with arterial monitoring, and no difference in sensitivity, specicity, false negative rate, salvage rate, or ap failure rate between venous and arterial implantable
Doppler probes; however, the clinical signicance of these ndings is not ascertained due to study limitations [65].
Tissue Spectroscopy (Visible Light andNear Infrared)
Tissue spectroscopy is a noninvasive, continuous method of monitoring of ap perfusion and can further be subclassied as either visible light spectroscopy or near
infrared spectroscopy. Visible light spectroscopy (VLS) uses shallow penetrating
9 Trends inMicrovascular Surgery
https://t.me/medicina_free
visible light (475–625nm) to measure tissue hemoglobin saturation at the capillary
level [66]. Decreases in tissue oxygen saturation suggest arterial inow compromise
related to an isolated arterial thrombosis or a venous thrombosis impeding arterial
inow. Additionally, total hemoglobin concentration is measured to quantify venous
drainage, providing an indirect measure of blood volume within the ap. Increased
total hemoglobin concentration suggests venous drainage compromise. A prospective controlled study comparing VLS and clinical examination with intermittent
Doppler in the postoperative monitoring of free aps found that VLS was able to
detect compromised ap perfusion prior to changes in physical exam or handheld
Doppler, resulting a 100% successful ap salvage in cases of compromised ap
perfusion [67]. Limitations of VLS technology include the need for an external skin
paddle larger than 2cm, which precludes its use with buried aps and the inability
of the probe to adhere to mucosal surfaces, limiting its use in oral reconstructions.
Additionally, instability in SpO2 values during the rst 8h following arterial anastomosis potentially secondary to mild ischemia-reperfusion injury with free ap
transfer can obfuscate potential vascular compromise of the ap [67].
Near-infrared spectroscopy (NIRS) monitors changes in tissue perfusion and
oxygenation status based on the differential scattering and absorption of infrared
light by tissue chromophores contained in hemoglobin, allowing for real-time measurement of oxygenated, deoxygenated, and total hemoglobin concentrations and
detection of altered tissue hemodynamics and potential ap compromise [68].
Postoperative NIRS monitoring allows for earlier detection of subclinical vascular
compromise resulting in lower ap loss rates and improved salvage rates as compared to clinical assessment with handheld Doppler [69]. A recent systematic review
found that in comparison to free aps with vascular compromise monitored clinically, aps monitored with NIRS had a signicantly higher salvage rate (89% vs.
50%), a lower rate of partial loss (15% vs. 80%), and an earlier detection of vascular
compromise of approximately 82min [68].
VLS confers several advantages over NIRS.The absorption of visible light by
hemoglobin is 100 times that of infrared light, allowing for more sensitive evaluation of variation in tissue oxygenation. Additionally, the smaller VLS probe, as narrow as 6 mm, allows for easier adaptation to tissue surfaces for monitoring as
compared to the larger NIRS probe. Conversely, NIRS can monitor to greater depth
as compared to VLS, up to 30mm, which may be useful for evaluating some buried
aps [70].
185
Conclusion
The eld of microsurgery has signicantly evolved over the past century. Advances
in preoperative imaging have allowed for more sensitive assessment of donor site
vessel anatomy and perforator planning. Venous coupler systems decrease operative
time while maintaining low rates of venous thrombosis. Implantable Doppler probe
systems allow for improved ap monitoring, resulting in earlier detection of
186
https://t.me/medicina_free
A. Beech and J. Moe
microvascular thrombosis and ap compromise. Multiple technologies are available
to the microvascular reconstructive surgeon to optimize the preoperative assessment, intraoperative microvascular anastomosis, and postoperative monitoring of
free aps; however, these should be considered as adjunctive tools to supplement
rather than replace clinical judgment and excellent surgical technique. These
advances have allowed for improved ap predictability and a shift toward custom
personalized reconstructions with the goal of providing improved functional and
esthetic outcomes in microvascular reconstruction.
References
1. Friedman SG.The end-to-end anastomosis of John B.Murphy. J Vasc Surg. 2015;62(2):515–7.
2. Moritz WR, Raman S, Pessin S, Martin C, Li X, Westman A, Sacks JM.The history and innovations of blood vessel anastomosis. Bioengineering (Basel). 2022;9(2):75.
3. Seidenberg B, Rosenak SS, Hurwitt ES, Som ML.Immediate reconstruction of the cervical
esophagus by a revascularized isolated jejunal segment. Ann Surg. 1959;149(2):162–71.
4. Jacobson JH II, Suarez EL. Microsurgery in anastomosis of small vessels. Surg Forum.
1960;11:243–5.
5. McLean DH, Buncke HJ Jr. Autotransplant of omentum to a large scalp defect, with microsurgical revascularization. Plast Reconstr Surg. 1972;49(3):268–74.
6. Hidalgo DA.Fibula free ap: a new method of mandible reconstruction. Plast Reconstr Surg.
1989;84(1):71–9.
7. Tamai S.History of microsurgery—from the beginning until the end of the 1970s. Microsurgery.
1993;14(1):6–13.
8. Giunta RE, etal. The value of preoperative Doppler sonography for planning free perforator
aps. Plast Reconstr Surg. 2000;105(7):2381–6.
9. Garvey PB, Chang EI, Selber JC, Skoracki RJ, Madewell JE, Liu J, Yu P, Hanasono
MM. A prospective study of preoperative computed tomographic angiographic mapping
of free bula osteocutaneous aps for head and neck reconstruction. Plast Reconstr Surg.
2012;130(4):541e–9e.
10. Rozen WM, etal. The accuracy of computed tomographic angiography for mapping the perforators of the DIEA: a cadaveric study. Plast Reconstr Surg. 2008;122(2):363–9.
11. Battaglia S, et al. Osteomyocutaneous bular ap harvesting: computer-assisted planning
of perforator vessels using computed tomographic angiography scan and cutting guide. J
Craniomaxillofac Surg. 2017;45(10):1681–6.
12. Ettinger KS, Morris JM, Alexander AE, Nathan JM, Arce K.Accuracy and precision of the
computed tomographic angiography perforator localization technique for virtual surgical planning of composite Osteocutaneous bular free aps in head and neck reconstruction. J Oral
Maxillofac Surg. 2022;S0278-2391(22):00238–5.
13. Smit JM, etal. Preoperative CT angiography reduces surgery time in perforator ap reconstruction. J Plast Reconstr Aesthet Surg. 2009;62(9):1112–7.
14. Nassar AH, et al. Comparison of various modalities utilized for preoperative planning
in microsurgical reconstructive surgery. J Reconstr Microsurg. 2021;38:170. https://doi.
org/10.1055/s- 0041- 1736316.
15. Rodkin B, etal. A review of visualized preoperative imaging with a focus on surgical procedures of the breast. Gland Surg. 2019;8(S4):S301–9.
16. Futran ND, Stack BC Jr, Zaccardi MJ.Preoperative color ow Doppler imaging for bula free
tissue transfers. Ann Vasc Surg. 1998;12(5):445–50.
17. Dorfman D, Pu LLQ.The value of color duplex imaging for planning and performing a free
anterolateral thigh perforator ap. Ann Plast Surg. 2014;72(Supplement 1):S6–8.
9 Trends inMicrovascular Surgery
https://t.me/medicina_free
18. Cho M-J, et al. The role of duplex ultrasound in microsurgical reconstruction: review and
technical considerations. J Reconstr Microsurg. 2020;36(07):514–21.
19. John HE, Niumsawatt V, Rozen WM, Whitaker IS.Clinical applications of dynamic infrared
thermography in plastic surgery: a systematic review. Gland Surg. 2016;5(2):122–32.
20. Muntean MV, et al. Dynamic infrared mapping of cutaneous perforators. J Xiangya Med.
2018;3:16. https://doi.org/10.21037/jxym.2018.04.05. Accessed 23 Jan 2022.
21. Sheena Y, Jennison T, Hardwicke JT, Titley OG.Detection of perforators using thermal imaging. Plast Reconstr Surg. 2013;132(6):1603–10.
22. Hardwicke JT, et al. Detection of perforators using smartphone thermal imaging. Plast
Reconstr Surg. 2016;137(1):39–41.
23. de Weerd L, etal. The value of dynamic infrared thermography (DIRT) in perforator selection
and planning of free DIEP aps. Ann Plast Surg. 2009;63(3):274–9. https://doi.org/10.1097/
sap.0b013e318190321e.
24. Weum S, etal. Evaluation of dynamic infrared thermography as an alternative to CT angiography for perforator mapping in breast reconstruction: a clinical study. BMC Med Imaging.
2016;16(1):43.
25. Chubb DP, Taylor GI, Ashton MW. True and ‘choke’ anastomoses between perforator angiosomes: part II. Dynamic thermographic identication. Plast Reconstr Surg.
2013;132(6):1457–64.
26. Leveen HH. Nonsuture method for vascular anastomosis utilizing the Murphy button principle. Arch Surg (1920). 1949;58(4):504–10. https://doi.org/10.1001/
archsurg.1949.01240030512010.
27. Ostrup LT, Berggren A. The UNILINK instrument system for fast and safe microvascular
anastomosis. Ann Plast Surg. 1986;17(6):521–5.
28. Nakatsuka T, Harii K, Asato H, Takushima A, Ebihara S, Kimata Y, Yamada A, Ueda K,
Ichioka S.Analytic review of 2372 free ap transfers for head and neck reconstruction following cancer resection. J Reconstr Microsurg. 2003;19(06):363–8.
29. Grewal A, Erovic B, Struman N, etal. The utility of the microvascular anastomotic coupler in
free tissue transfer. Can J Plast Surg. 2012;20(02):98.
30. Shindo M, Costantino P, Nalbone V, Rice D, Sinha U. Use of a mechanical microvascular
anastomotic device in head and neck free tissue transfer. Arch Otolaryngol Head Neck Surg.
1996;122(5):529–32.
31. Spector JA, etal. Routine use of microvascular coupling device for arterial anastomosis in
breast reconstruction. Ann Plast Surg. 2006;56(4):365–8.
32. Shindo ML, etal. Use of a mechanical microvascular anastomotic device in head and neck free
tissue transfer. Arch Otolaryngol Head Neck Surg. 1996;122(5):529–32.
33. DeLacure MD, etal. Clinical experience with a microvascular anastomotic device in head and
neck reconstruction. Am J Surg. 1995;170(5):521–3.
34. Patanis G, etal. Microvascular anastomotic arterial coupling: a systematic review. J Plast
Reconstr Aesthet Surg. 2021;74(6):1286–302.
35. GEM Synovis MCA. Microvascular anastomotic coupler. https://www.synovismicro.com/
html/products/gem_microvascular_anastomotic_coupler.html.
36. Rickard RF, Hudson DA.A history of vascular and microvascular surgery. Ann Plast Surg.
2014;73(4):465–72.
37. Liczbik O, etal. From magnifying glass to operative microscopy—the historical and modern
role of the microscope in microsurgery. Pol J Pathol. 2019;70(1):14–20.
38. De Virgilio A, etal. Free ap microvascular anastomosis in head and neck reconstruction
using a 4K three-dimensional exoscope system (VITOM 3D). Int J Oral Maxillofac Surg.
2020;49(9):1169–73.
39. Karl Storz-Endoskope. VITOM® 3D—3D visualization for microsurgery and open surgery.
https://www.karlstorz.com/de/en/microscopy.htm.
40. Olympus. ORBEYE™ exoscope. https://medical.olympusamerica.com/products/orbeye.
41. Ahmad FI, etal. Application of the ORBEYE three‐dimensional exoscope for microsurgical
procedures. Microsurgery. 2019;40(4):468–72.
187
188
https://t.me/medicina_free
42. Patanis G, etal. The exoscope versus operating microscope in microvascular surgery: a simulation non-inferiority trial. Arch Plast Surg. 2020;47(03):242–9.
43. Piatkowski AA, Keuter XHA, Schols RM, van der Hulst RRWJ. Potential of performing a
microvascular free ap reconstruction using solely a 3D exoscope instead of a conventional
microscope. J Plast Reconstr Aesthet Surg. 2018;71:1664–78.
44. BHS Technologies. The RoboticScope®. https://www.bhs- technologies.com/
the- robotic- scope- change- of- perspective/.
45. Boehm F, etal. Performance of microvascular anastomosis with a new robotic visualization
system: proof of concept. J Robot Surg. 2021;16(3):705–13.
46. Pruimboom T, etal. Optimizing Indocyanine green uorescence angiography in reconstructive
ap surgery: a systematic review and exvivo experiments. Surg Innov. 2019;27(1):103–19.
47. Ott P.Hepatic elimination of Indocyanine green with special reference to distribution kinetics
and the inuence of plasma protein binding. Pharmacol Toxicol. 1998;83:1–48.
48. Starosolski Z, etal. Indocyanine green uorescence in second near-infrared (NIR-II) window.
PloS One. 2017;12(11):e0187563.
49. Alander JT, etal. A review of Indocyanine green uorescent imaging in surgery. Int J Biomed
Imaging. 2012;2012:1.
50. Li K, etal. Application of indocyanine green in ap surgery: a systematic review. J Reconstr
Microsurg. 2017;34(02):077–86.
51. Bigdeli AK, Thomas B, Falkner F, Gazyakan E, Hirche C, Kneser U. The impact of
Indocyanine-green uorescence angiography on intraoperative decision-making and postoperative outcome in free ap surgery. J Reconstr Microsurg. 2020;36(8):556–66.
52. Holm C, Mayr M, Höfter E, Dornseifer U, Ninkovic M.Assessment of the patency of microvascular anastomoses using microscope-integrated near-infrared angiography: a preliminary
study. Microsurgery. 2009;29(07):509–14.
53. La Padula S, et al. Intraoperative use of Indocyanine green angiography for selecting the
more reliable perforator of the anterolateral thigh ap: a comparison study. Microsurgery.
2018;38(7):738–44. https://doi.org/10.1002/micr.30326.
54. Ritschl LM, et al. Comparison between different perforator imaging modalities for the
anterolateral thigh perforator ap transfer: a prospective study. J Reconstr Microsurg.
2020;36(09):686–93. https://doi.org/10.1055/s- 0040- 1714425.
55. Onoda S, etal. Preoperative identication of perforator vessels by combining MDCT, Doppler
owmetry, and ICG uorescent angiography. Microsurgery. 2013;33(4):265–9.
56. Chubb D, etal. The efcacy of clinical assessment in the postoperative monitoring of free
aps: a review of 1140 consecutive cases. Plast Reconstr Surg. 2010;125(4):1157–66. https://
doi.org/10.1097/prs.0b013e3181d0ac95. Accessed 12 Nov 2021.
57. Hartley CJ, Cole JS. A single-crystal ultrasonic catheter-tip velocity probe. Med Instrum.
1974;8(4):241–3.
58. Swartz WM, Jones NF, Cherup L, Klein A.Direct monitoring of microvascular anastomoses
with the 20-MHz ultrasonic Doppler probe: an experimental and clinical study. Plast Reconstr
Surg. 1988;81(2):149–61. https://doi.org/10.1097/00006534- 198802000- 00001.
59. GEM Synovis MCA.Flow coupler device and system. https://www.synovismicro.com/html/
products/gem_ow_coupler_device_and_system.html.
60. Schmulder A, etal. Eight-year experience of the cook-swartz Doppler in free-ap operations: microsurgical and reexploration results with regard to a wide spectrum of surgeries.
Microsurgery. 2011;31(1):1–6. https://doi.org/10.1002/micr.20816. Accessed 13 May 2022.
61. Wax MK. The role of the implantable Doppler probe in free ap surgery. Laryngoscope.
2014;124(S1):S1–S12.
62. Chang EI, etal. Deciphering the sensitivity and specicity of the implantable Doppler probe in
free ap monitoring. Plast Reconstr Surg. 2016;137(3):971–6.
63. Rosenberg JJ, etal. Monitoring buried free aps: limitations of the implantableDopplerand use
of color duplex sonography as a conrmatory test. Plast Reconstr Surg. 2006;118(1):109–13.
A. Beech and J. Moe
9 Trends inMicrovascular Surgery
https://t.me/medicina_free
64. Karinja SJ, Lee BT.Advances in ap monitoring and impact of enhanced recovery protocols. J
Surg Oncol. 2018;118(5):758–67. https://doi.org/10.1002/jso.25179. Epub 2018 Aug 21.
65. Klifto KM, Milek D, Gurno CF, Seal SM, Hultman CS, Rosson GD, Cooney DS.Comparison
of arterial and venous implantable Doppler postoperative monitoring of free aps: systematic review and meta-analysis of diagnostic test accuracy. Microsurgery. 2020;40(4):501–11.
https://doi.org/10.1002/micr.30564. Epub 2020 Feb 7.
66. Fox PM, Zeidler K, Carey J, Lee GK. White light spectroscopy for free ap monitoring.
Microsurgery. 2012;33(3):198–202.
67. Mericli AF, et al. A prospective clinical trial comparing visible light spectroscopy to
handheld Doppler for postoperative free tissue transfer monitoring. Plast Reconstr Surg.
2017;140(3):604–13.
68. Newton E, etal. Outcomes of free ap reconstructions with near‐infrared spectroscopy (NIRS)
monitoring: a systematic review. Microsurgery. 2020;40(2):268–75.
69. Koolen PGL, etal. Does increased experience with tissue oximetry monitoring in microsurgical breast reconstruction Lead to decreased ap loss? The learning effect. Plast Reconstr Surg.
2016;137(4):1093–101.
70. Lindelauf AAMA, et al. Near-infrared spectroscopy (NIRS) versus hyperspectral imaging (HSI) to detect ap failure in reconstructive surgery: a systematic review. Life (Basel).
2022;12(1):65.
189
Chapter 10
https://t.me/medicina_free
Use ofThree-Dimensional Technology
forVirtual Surgical Planning inOral
andMaxillofacial Surgery
SalahAlDinAl Azri , YohaannAliGhosh , andJonathanShum
Introduction
The use of virtual surgical planning has had a signicant impact on oral and maxillofacial surgery. Virtual planning has been utilized since 1980 and has now been
implemented into all aspects of osseous surgery and reconstructions of the face. The
success of these virtually planned cases depends on each step of the workow process: patient workup, quality of the image modality, data acquisition, virtual planning, and surgical execution. Each component of the process should be thorough
and meticulous in order to minimize the possibility of error during the surgical
execution. The overwhelming utility of virtual surgical planning and the ability to
create guides and implants to translate virtual reconstructions into reality have led
to increased efciency, reduce costs, and ultimately improve surgical outcomes.
S. A. D. Al Azri (*)
Maxillofacial Oncology and Microvascular Reconstructive Surgery, Houston, TX, USA
Department of Oral and Maxillofacial Surgery, The University of Texas Health Science
Center at Houston, Houston, TX, USA
e-mail: salah.al.din.alazri@uth.tmc.edu
Y. A. Ghosh
School of Medicine and Dentistry, Grifth University, Gold Coast, Australia
Integrated Prosthetics and Reconstruction, Department of Head and Neck Surgery, Chris
O’Brien Lifehouse, Sydney, NSW, Australia
e-mail: yohaann.ghosh@lh.org.au
J. Shum
Maxillofacial Oncology and Microvascular Reconstructive Surgery, Houston, TX, USA
Department of Oral and Maxillofacial Surgery, The University of Texas Health Science
Center at Houston, Houston, TX, USA
The University of Texas Health Science Center at Houston, Houston, TX, USA
e-mail: jonathan.shum@uth.tmc.edu
© The Author(s), under exclusive license to Springer Nature
Switzerland AG 2023
J. C. Melville et al. (eds.), Advancements and Innovations in OMFS, ENT, and
Facial Plastic Surgery, https://doi.org/10.1007/978-3-031-32099-6_10
191
192
https://t.me/medicina_free
S. A. D. Al Azri et al.
These processes and applications are outlined in this chapter to provide an overview
of the advancements that allow for accurate maxillofacial reconstructions.
Imaging Modality Hard Tissue Considerations
The initial step of virtual surgical planning necessitates obtaining the appropriate
images that are processed, used for planning sessions and construction of the
appropriate surgical guides and hardware. Different imaging modalities have different spatial and contrast resolution. Spatial resolution is the ability for an image
modality to differentiate between two separate objects in a radiographic image,
whereas contrast resolution is the ability to differentiate image intensities
between two areas (i.e., fat stranding vs. normal adipose tissue) [1] (Fig.10.1).
Fig. 10.1 (a) Inferior
alveolar nerve location
within the mandible
rendered from computed
tomography (CT) scan. (b)
Depth determined in
millimeters from mandible
buccal cortex. (Courtesy of
KLS Martin group)
a
b
Соседние файлы в папке Библиотека им академика М.И. Перельмана