MD Codes™: A Methodological Approach to Facial Aesthetic Treatment with Injectable Hyaluronic Acid Fillers (2024)

Background

Patients often seek aesthetic correction of facial deficiencies (e.g., lines and folds) that are rarely the underlying cause of dissatisfaction with their appearance. Use of a more holistic approach focused on improving the emotional messages of the face (e.g., looking less sad) may improve patient satisfaction with treatment outcomes. The MD Codes™ system was developed to increase clinician success rates by reducing variability in the technical aspects of hyaluronic acid (HA) filler treatment and focusing on addressing unfavorable emotional attributes of the face.

Methods

The MD Codes, or medical codes, represent specific anatomical subunits for injection of HA fillers. Each MD Code includes information regarding the target depth of injection, the proper delivery tool (needle or cannula) and delivery technique (e.g., aliquot, bolus, fanning), and the minimum product volume recommended to achieve visible, reproducible results (active number). During treatment planning, the appropriate MD Codes are selected using algorithms focused on lessening unfavorable facial attributes (a saggy, tired, sad, or angry look) and enhancing positive attributes (an attractive, younger, more contoured, or feminine [soft] or masculine look).

Results

Three case studies are presented to illustrate how the MD Codes and their algorithms were used to address sagginess, tiredness, and sadness in two women and one man.

Conclusions

MD Codes provide a universal symbolic language for reducing variability in injection technique. The platform provides user-friendly algorithms to help clinicians increase patient satisfaction by going beyond treatment of lines and folds and to focus on reducing unfavorable facial attributes.

Level of Evidence IV

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266.

Electronic supplementary material

The online version of this article (10.1007/s00266-020-01762-7) contains supplementary material, which is available to authorized users.

Keywords: Aesthetics, Dermal fillers, Hyaluronic acid, Rejuvenation, Skin aging, Skin wrinkling

Table1.

Key sources of variability in minimally invasive aesthetic treatment outcomes

Table2.

Summary of the components of the MD Codes

Component	Meaning
Letter	The anatomical area (e.g., Ck = cheek)
Number	The subunits of the anatomical unit (e.g., Ck1 = zygomatic arch; Ck2 = zygomatic eminence)
Number location	The side of the face (e.g., Ck1 r = the zygomatic arch on the right side; Ck1 l = the zygomatic arch on the left side)
Number position	Superscript (Xn) refers to upper areas (e.g., Lp1 = vermilion body of the upper lip) Subscript (Xn) refers to lower areas (e.g., Lp1 = vermilion body of the lower lip)
Color	Red color denotes alert areas, and additional caution must be taken if injecting at or near these sites, for patient safety
Shape	Technical delivery of the product (e.g.,  = needle,  = cannula,  = fanning,  = aliquots;  = bolus)

Table3.

MD codes and injection guidance for anatomical sites using hyaluronic acid fillers

Anatomical unit MD code	Injection area	Target depth of injection	Injection device	Injection delivery	Alerts	Active number per side (mL)a
Foundation
Cheek (Ck)
Ck1	Zygomatic arch	Supraperiostealb	Needle			0.1 + 0.1 + 0.1c
Ck1 TML	Zygomatic arch	Sub-SMAS	Cannula			0.5
Ck2	Zygomatic eminence	Supraperiostealb	Needle		Be wary of the zygomaticofacial arteryd	0.2
Ck3	Anteromedial cheek	Supraperiostealb	Needle		Be wary of the infraorbital arteryd	0.3
		Deep malar fat pad	Cannula			0.5
		SOOF	Cannula			0.5
Ck4	Lateral lower cheek/parotid area	Subcutaneous	Cannula		Be wary of the parotid gland	0.5
Ck5	Submalar/buccal area	Subcutaneous	Cannula		Be wary of the buccal nerve, facial vein and artery	0.5
Contour
Upper face
Temple (T)
T1	Anterior temple	Supraperiostealb	Needle		Be wary of the superficial frontal artery and the deep temporal arteriesd	0.5
T2	Posterior temple	Supraperiostealb	Needle		Be wary of the superficial frontal artery and deep temporal arteriesd	0.5
T1/T2	Anterior and posterior temple	Temporal fascia	Cannula			0.5
Lower face
Chin (C)
C1	Labiomental angle	Subcutaneous	Cannula			0.5e
C2	Chin apex	Subcutaneous	Cannula			0.3
	Chin apex	Supraperiostealb	Needled			0.3 (only midline)
C3	Anterior chin	Supraperiostealb	Needled		Do not go too lateral due to mental arteryd	0.3
C4	Anterior chin/soft tissue pogonion	Subcutaneous	Needle			0.3 (only midline)
C5f	Lateral lower chin	Supraperiostealb	Needled			0.3
C6	Lateral chin	Subcutaneous	Cannula			0.5
Jowls (Jw)
Jw1	Mandible angle	Supraperiostealb	Needled			0.5
Jw1	Mandible angle	Subcutaneous	Cannula			0.5
Jw2	Pre-auricular area	Subcutaneous	Cannula		Be wary of parotid gland	0.5
Jw3	Mandible body	Subcutaneous	Cannula		Be wary of the superficial temporal artery and the parotid gland	1.0
Jw4	Lower prejowl	Subcutaneous	Cannula			0.5
Jw5	Lower anterior chin	Subcutaneous	Cannula			0.5
Refinement
Periorbital
Forehead (F)g,h					Injection should be avoided in the 2-cm region above the orbit
F1	Medial forehead	Supraperiostealb	Cannula		Be wary of the supraorbital artery	0.5
F2	Lateral forehead	Supraperiostealb	Cannula		Be wary of the superficial temporal artery	0.5
F3	Central forehead	Supraperiostealb	Cannula		Be wary of the supratrochlear artery	0.5
Lateral orbital (O)
O1	Central lateral orbital	Supraperiostealb	Cannula	Figh	Avoid injecting into the lower eyelid	0.2
O2	Lower lateral orbital	Supraperiostealb	Cannula		Avoid injecting into the lower eyelid	0.2
O3	Upper lateral orbital	Supraperiostealb	Cannula		Avoid injecting into the upper eyelid	0.1
Eyebrow (E)h
E1	Eyebrow tail	ROOF	Cannula			0.2
E2	Eyebrow center	ROOF	Cannula		Inject lateral to the supraorbital foramen	0.2
E3	Eyebrow head	ROOF	Cannula		Inject lateral to the supratrochlear foramen	0.1
Tear trough (Tt)i
Tt1	Central infraorbital	Supraperiostealb	Cannula		Be wary of the infraorbital artery branchesi	0.2
Tt2	Lateral infraorbital	Supraperiostealb	Cannula			0.2
Tt3	Medial infraorbital	Supraperiostealb	Cannula		Be wary of the angular artery and veini	0.1
Glabella (G)i
G1	Lateral glabella	Supraperiostealb	Cannula		Be wary of the neurovasculature in the glabellar region, in particular the supratrochlear arteries	0.1
G2	Central glabella	Supraperiostealb	Cannula			0.3 (only midline)
Perioral
Nasolabial fold (NL)
Bone deficiencyj
NL1	Upper nasolabial fold	Supraperiostealb	Needlej		Be wary of the facial artery and the branches to the nasal flared,	0.3
Mild/moderatek
NL1	Upper nasolabial fold	Subcutaneous	Cannula		Be wary of the facial artery and the branches to the nasal flare	0.3
NL2	Central nasolabial fold	Subcutaneous	Cannula		Be wary of the facial artery	0.2
Severek
NL1	Upper nasolabial fold	Subcutaneous	Cannula		Be wary of the facial artery and the branches to the nasal flare	0.5
NL2	Central nasolabial fold	Subcutaneous	Cannula		Be wary of the facial artery	0.3
NL3	Lower nasolabial fold	Subcutaneous	Cannula		Be wary of the facial artery	0.2
Marionette line (M)
M1	Upper marionette line	Subdermal	Needle			0.2
M2	Central marionette line	Subdermal	Needle			0.2
M3	Lower marionette line	Subdermal	Needle			0.1
Lip (Lp)
Lp1	Vermilion body
Lp1	Upper lip	Submucosa	Cannula			0.2
Lp1	Lower lip	Submucosa	Cannula			0.2
Lp2	Cupid’s bow	Mucosa	Needle			0.05
Lp3	Lip border
Lp3	Upper lip	Mucosa	Needle			0.15
Lp3	Lower lip	Mucosa	Needle			0.15
Lp4	Medial tubercle	Mucosa	Needle		Be wary of the superior labial artery	0.1 (only midline)
Lp5	Lateral tubercles	Mucosa	Needle		Be wary of the inferior labial artery	0.05
Lp6	Oral commissure	Mucosa	Needle			0.1
Lp7	Philtrum column	Subdermal	Needle			0.05
Lp8	Perioral lines
Lp8	Upper perioral lines	Subcutaneous	Cannula	l		0.25
Lp8	Lower perioral lines	Subcutaneous	Cannula	l		0.25
Other
Nose (N)h
N1	Anterior nasal spine (nasolabial angle)	Supraperiostealb	Needled			0.3 (only midline)
		Supraperiostealb	Cannulam			0.3 (only midline)
N2	Columella (anterior septum)	Cartilageb	Needle			0.2 (only midline)
		Cartilageb	Cannulam
N3	Frontonasal angle	Supraperiostealb	Needled			0.3 (only midline)
		Supraperiostealb	Cannulam
N4	Bony dorsum	Supraperiostealb	Needled			0.2 (only midline)
		Supraperiostealb	Cannulam
N5	Cartilaginous dorsum	Cartilageb	Needled			0.2 (only midline)
		Cartilageb	Cannulam

Table4.

Checklist of standard equations for treating facial deficiencies with the MD codes

Algorithms for Selecting MD Codes

To handle the enormous variability among faces, the MD Codes algorithms were developed to guide selection of the appropriate MD Codes for each individual. Not every patient will need all of the codes within each equation. For example, the algorithm for saggy cheeks (Fig.2a) guides the selection of MD Codes based on the presence or absence of volume loss. When comparing a daughter, a mother, and a grandmother, the daughter may have fullness in her cheek area and present with only a mild degree of sagginess. Thus, according to the saggy cheeks algorithm, she would benefit from treatment of only Ck1. The mother may present with sagginess and volume loss concentrated only in the medial aspect. She may benefit from treatment of Ck1, Ck3, and Ck4. The grandmother, due to a greater severity of volume loss and sagginess, may be eligible for treatment of all five cheek anatomical areas (Ck1+Ck2+Ck3+Ck4+Ck5).

Someone with a tired look may also present with sunken temples. The algorithm for sunken temples (Fig.2b) guides clinicians on the selection of MD Codes based on the severity of volume loss in the temples. In the case of the daughter, the mother, and the grandmother, the daughter may not need any temple treatment as she may have no deficiency there. The mother may present with mild to moderate volume deficit in the temples and may benefit only from treatment of T1. The grandmother, with a more severe temple deficiency, may benefit from treatment of T1 and T2.

The algorithms for treatment of the tear troughs and the eye bags are shown in Fig.2c and d, respectively. The vast majority of people presenting with distracting tear troughs and eye bags also have saggy cheeks and/or volume loss that would first require treatment of the cheeks (foundation) and the temples (contouring). Only a young patient who presents with no volume loss or sagginess may benefit from direct treatment of the tear troughs (Tt1 + Tt2 + Tt3), but this rarely occurs in clinical practice.

Combining the MD Codes identified using the three algorithms to treat a tired look may result in, for example, a total of seven MD Codes for the mother ([Ck1 + Ck3 + Ck4] + [T1] + [Tt1 + Tt2 + Tt3]), and 10 codes for the grandmother ([Ck1 + Ck2 + Ck3 + Ck4 + Ck5] + [T1 + T2] + [Tt1 + Tt2 + Tt3]). Thus, the difference between the treatment plans for the mother and the grandmother is in the number of codes, based on degree of severity; the grandmother does not necessarily receive more volume per code, which could lead to unnatural results and adverse events. Once the MD Codes are selected for the individual patient, a tired look is addressed step by step, first providing foundation in the midface, then contouring at the temples, and, finally, directly addressing the tear troughs or eye bags as refinement. Additional MD Codes algorithms are provided in Figure S1 in the Supplemental Materials. Clinicians must explain to patients who focus only on the refinement step that the foundation and contour should be addressed first, as represented in these algorithms.

Over the foundation, contour, and refinement steps, the MD Codes approach can result in the progressive removal of the unfavorable attributes of tiredness, sadness, and sagginess, and may enhance the positive attributes of looking younger and more feminine. Figure3 illustrates the change in appearance that may be observed as additional MD Codes are used to add volume in successive treatment steps. Notice the improvement in the patient’s cheek immediately after providing midface foundation (Ck1 + Ck2 + Ck3 + Ck4) and contouring of the upper face (T1) with a total 4mL of HA filler. The patient’s jawline was improved after contouring of the lower face with an additional 4mL of HA filler (C1 + C2 + Jw4 + Jw5). Improvement in her double chin was also achieved by addressing the cheek first, then contouring the chin and anterior jawline. Foundation and contour were reinforced with additional codes (Ck3 + C6), refinement of the periorbital area improved the tear troughs (Tt1 + Tt2 + Tt3), and perioral refinement addressed the lips and nasolabial folds (Lp₁ + Lp2 + Lp³ + Lp₃ + Lp5 + Lp6 + NL1) using a final 9mL of filler. The image on the right in Fig.3 shows the patient immediately after the total injection volume of 17mL. Increasing the number of MD Codes over these multiple treatment steps yielded more impactful results. This patient received all treatment steps in a single session; however, the author suggests planning treatment such that 4mL is injected per session. To achieve the best possible results, more volume may be provided by using additional codes in successive sessions to reinforce facial restructuring in the midface, cheek, and jawline.

Volume Planning: The MD Codes Active Numbers

One of the biggest challenges clinicians may encounter during treatment planning is estimating the total volume of product required for treatment. Often a clinician may discover mid-treatment that the planned number of syringes is not adequate. When fillers were first introduced to the market, it was common for clinicians to treat only nasolabial folds or to distribute the product of one syringe (1mL) among many sites, leading to a lack of visible results and patient dissatisfaction. Clinical judgment should be used to determine the appropriate total volume based on individual patient needs; however, a recommended injection volume, or active number, is provided with each MD Code to simplify the estimation of the total volume. The active numbers are minimum volumes needed to achieve visible and reproducible results (Table3); actual injection volumes should be determined by the clinician for each patient.

The analogy of building a house is again useful for understanding the importance of volume planning. The amount of material to be used in each stage of construction is critical and must be carefully calculated in advance, in order to create a financial plan and ensure that the structure will be sound. Similarly, clinicians must know beforehand how many syringes they will need for each treatment step, to be able to communicate accurate cost information to the patient and to achieve optimal and long-lasting results.

Volume recommendations provided here (and to be presented in greater detail in a future publication) were established progressively by the author based on clinical experience with more than 10,000 syringes over a 4-year period. Clinicians may follow a simple rule: bolus injections should not exceed a total volume of 0.3mL into the same compartment, to avoid disturbing muscle movement. There are three exceptions to this rule: when injecting the temple (T1+T2) and the mandible angle (Jw1), the active numbers are 0.5mL. When fanning in a specific area with a cannula, no less than 0.5mL should be used.

To estimate the product volume needed during treatment planning, clinicians should first determine the MD Codes required for their patient, using the algorithms as described above. The active numbers for each code are then summed to estimate the minimum total volume required. For example, treating a tired look may require the following MD Codes:

Note that when both Ck1 and T1 are injected during the same session, the active number for T1 is increased from 0.5 to 0.7mL to allow for use of an entire 1-mL syringe. For this specific treatment, the clinician will need a total of four syringes, two for each side of the face. All patients whose treatment plans include the same MD Codes will start at the same estimated minimum total volume. In this way, the MD Codes approach reduces variability in outcomes by focusing on facial attributes rather than on the differences in age, gender, and ethnicity in the faces that harbor them.

Case Study 1

A 43-year-old Caucasian woman (Fig.4) presented with signs of sagginess in the midface and lower face, looking tired around the eyes and looking sad around the eyes and mouth. The first step of treatment provided foundation in the midface by addressing the cheek codes. The algorithm for saggy cheeks was used to select the MD Codes for injection and, as mentioned previously, always starts with the lateral lifting cheek vectors (Ck1 + Ck4) and proceeds to the anterior (Ck2) and medial (Ck3) cheek. Contour was then provided to the upper face by addressing the volume deficit in the temple (T1), which indirectly improved the appearance of her eye bags. Next, the lower face was contoured by injecting C1 to improve the labiomental angle, C2 to increase the vertical height of the chin, and Jw4 and Jw5 to advance the mandible and to improve the prejowl area. Midface foundation was reinforced by injecting Ck3 with two different approaches, first the deep malar fat pad, then the suborbicularis oculi fat (SOOF). The lateral aspects of the chin and prejowl areas were also addressed by injecting C6. Finally, periorbital refinement was provided in the tear trough area (Tt1 + Tt2 + Tt3). Refinement in the perioral area was provided by addressing the nasolabial folds (NL1 + NL2) and lip volume (Lp¹+ Lp₁+ Lp⁶). Lastly, Jw1 was injected to reshape the mandible angle.

Images taken immediately after treatment illustrate improvements in the patient’s midface, jawline, periorbital, and perioral areas (Fig.4a–c). The reshape of the jawline apparent in the oblique view (Fig.4b) was accomplished by contouring with injections in C1, C2, Jw4, Jw5, C6, and Jw1. In the oblique view, improvement of the eye bags was observed after injection of Ck1, T1, Ck2, Ck3 and Tt1, Tt2, Tt3. The periorbital lines improved after addressing periorbital deflation. In the photographs taken immediately after treatment, you can see that using the MD Codes algorithm to select codes and focusing treatment on foundation, contour, and refinement resulted in the elimination of the unfavorable tired, saggy, and sad attributes of the face and enhancement of the positive attributes of looking younger, more feminine, and attractive. This patient (and the following 2 cases) received all injections in a single session, for educational purposes. However, in clinical practice, this treatment could be provided in multiple sessions, with four syringes of HA filler injected during each session.

Case Study 2

A 44-year-old woman (Fig.5) presented with facial signs of sagginess, tiredness, and sadness, represented by the presence of saggy cheeks, eye bags, and marionette lines. Before treatment, indentation was apparent on the anterior right cheek when she smiled (Fig.5c). The first treatment step focused on providing foundation in the midface (Ck1 + Ck4) and contouring the upper face (T1). The second step addressed the lower face by treating the chin (C1 + C2) and anterior jawline (Jw4 + Jw5). In step 3, due to the degree of severity and to further improve the jawline, Jw4  and Jw5 were reinjected. In the same step, Ck3 was injected to compensate for the deep malar fat pad and then the SOOF. The final step included periorbital and perioral refinement through injections in the tear trough area (Tt1 + Tt2 + Tt3), the nasolabial folds (NL1 + NL2), and lip (Lp¹+ Lp₁+ Lp6). Images taken immediately after the last treatment step illustrate the changes in facial shape, including increased volume in the cheeks, and the more triangular appearance of the chin (Fig.5a). After the lip treatment, an upturn of the oral commissures was observed. In the oblique view, the improvement of saggy cheeks, eye bags, and the jawline resulted in a less tired, less saggy, and less sad appearance than before treatment (Fig.5b). Injection of CK1 and Ck4 improved cheek sagginess and reduced the indentation of the woman’s right cheek, making her smile appear more attractive and natural (Fig.5c).

Case Study 3

A 42-year-old Caucasian man (Fig.6) presented with a narrow face, saggy cheeks, a poorly defined jawline, and a double chin. The first treatment step focused on the same lateral lifting vectors as in case 2 (Ck1 +T1+Ck4) to build midface foundation and to contour the upper face. Step 2 focused on improving chin projection by treating the chin (C1 + C2) and jawline (Jw4 + Jw5) in the same manner that treatment was delivered for cases 1 and 2. For this patient, repeat treatment was required in a subsequent session due to the degree of severity. The lateral chin area and prejowl sulcus (C6), the lateral lower chin (C5), and the chin apex (C2) were then addressed. In addition, Ck1 was injected for the top-model look (TML; Ck1), which refers to the injection of Ck1 with a cannula to create a linear appearance of the zygomatic arch. Ck3 was injected to address the deep malar fat pad. Injection of Ck1 (TML) was repeated in a later session to further reinforce the zygomatic width, and Jw3 was injected to sharpen the jawline. Immediately after treatment, changes in facial shape could be observed, with improvements in the bitemporal, bizygomatic, and bigonial widths due to the injections of T1, Ck1, and Jw1, respectively (Fig.6a). Indirect improvements to the tear trough area could also be observed following the injection of Ck1, T1, and Ck3. The chin presented with a more square shape, and there was less indentation of the labiomental sulcus and the prejowl area. Note that C1, C2, C5, and C6 were injected, as well as Jw4 and Jw5, to improve chin shape and address the double chin. When the patient smiles, a reduction in his double chin and smile lines can be seen (Fig.6b). His smile looks more confident due to improvements in the lateral structure of the face (Ck1 + T1 + Ck4) and support of the deep malar fat pads (Ck3). Injection of C1 also lifted the lower lip and lessened showing of his lower teeth when smiling. The oblique view (Fig.6c) shows improved definition of the zygomatic arch resulting from Ck1 (TML), a better jaw angle due to treatment of Jw1, a more square chin shape due to treatment of C1, C2, C5, and C6, and a more defined jawline due to treatment of Jw3. When the patient looked down, the improvement of facial shape and increased stability in the lower lip helped to create a more confident appearance (Fig.6d).

Below is the link to the electronic supplementary material.

Conflict of interest

Maurício de Maio has served as a consultant for speaking events and medical education for Allergan plc. Some of the concepts included in this paper have been presented by the author in seminars as a part of an Allergan Medical Institute educational series, and images used in Fig.1 have been included in Allergan’s medical education materials.

Ethical Approval

This article does not contain any studies with human participants or animals performed by the author.

Informed Consent

Informed consent is not required for this type of study.

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