EXPLORE
Plastic Surgery
Dr. Barry Eppley

Explore the worlds of cosmetic
and plastic surgery with Indianapolis
Double Board-Certified Plastic
Surgeon Dr. Barry Eppley

Plastic surgery is one of the marvels of modern medicine, with a wide range of options for face and body improvements. And today’s media outlets make it easier than ever before to gather information on the latest plastic surgery procedures. But how does this information apply to you and your concerns?

Every person is unique and has his or her own desires. What procedure or combination of treatments is right for you? And what can you really expect? EXPLORE PLASTIC SURGERY with Dr. Barry Eppley, Indianapolis plastic surgeon, who can provide you with a wealth of practical and up-to-date insights into the world of plastic surgery through his regular blog posts. In his writings, Dr. Eppley covers diverse topics on facial and body contouring procedures. You will be sure to find useful information that will help broaden and enrich your plastic surgery education.

May 12th, 2014

Case Study: Saline Breast Augmentation in Young Asian Female

 

Background: Breast augmentation is done on many different types of women from a wide range of ages to numerous ethnicities. There are an incredible large number of breast implant types, styles and sizes from which to choose that can ultimately appeal to any woman considering the procedure.

But it is up to the plastic surgeon to listen to and appreciate the goals of each woman prior to surgery and the most contemplated issues is the size of the implant and the location of the incision.. While every women is unique and has her own desires, their ethnic background can factor into these decisions.

The Asian breast augmentation patient usually presents with several issues to consider. While an Asian female wants their breast to be larger, they still want them to be natural, not look overaugmented and fit their often smaller and more petite body frames. For most Asian women this means that the implants sizes are smaller than what most Caucasian women want and are often in the 250cc to 300cc volume range.

Scarring is of paramount concern to Asian women as their skin type is very prone to hyperpigmentation and prominent scars. Incisional options include either an intrareolar or axillary location to introduce the breast implants. Both can be effective and produce scars that are virtually invisible when healed. The small diameter of many Asian nipples may not allow the nipple approach to be used.

Case Study: This 18 year-old Asian female wanted breast augmentation due to her very small natural breast size. Because of her age, she could only get saline breast implants. Using a volumetric sizing method, she opted for a maximum size of 275cc.

Asian Female Breast Augmentation result front view Dr Barry Eppley IndianapolisUnder general anesthesia, she had a transaxillary approach done to place 250cc moderate plus profile saline implants which were filled to 275ccs on each side. The size of the axillary incisions was 2 cms placed in a high axillary skin fold right under the muscle edge.

Asian Female Breast Augmentation result oblique view Dr Barry Eppley IndianapolisShe was not seen again after surgery for five years when she wanted to increase the size of her implants as well as switch to new silicone implants. It is interesting to see her long-term natural looking breast augmentation result

Asian Female Breast Augmentation result side view Dr Barry Eppley IndianapolisAsian breast augmentation must consider the body shape of the Asian female and the potential for adverse scarring at the incision site. These often require a different approach than that of the Caucasian breast augmentation patient who often wants much bigger implants and whose scar naturally heals well in the inframammary location without hyperpigmentation.

Case Highlights:

1) Asian breast augmentation requires consideration of small petite body types and often requires the use of smaller breast implants.

2) Due to scarring concerns and hyperpigmentation, a transaxillary approach to Asian breast augmentation is often used.

3) Saline or small silicone breast implants can be placed through an armpit incisional technique.

Dr. Barry Eppley

Indianapolis, Indiana

May 11th, 2014

Tongue Patch Method For Short-term Weight Loss

 

There have been innumerable methods for weight loss over the years from simple pills to invasive bariatric surgery. All have been associated with varying degrees of success and durability. There is no one single method that works for or is for everyone. Surgical approaches are usually associated with the most rapid forms of weight loss although their relapse rates can be high.

Weight Loss Tongue PatchSurgical weight loss approaches are typically done when patients are either extremely obese (and needs large amounts of weight loss) or have not found success with diet and exercise efforts for a variety of reasons. One newer surgical weight loss method is that of the tongue patch. A small postage-size piece of thin synthetic mesh is sewn onto the surface of the tongue. This undoubtably limits the comfort of eating solid foods. Affecting the intake portion of the alimentary canal has always been a primary emphasis of all weight loss methods. This is just a mechanical method of doing so.

Tongue Patch for Weight Loss Indianapois Dr Barry EppleyIn the May issue of the American Journal of Cosmetic Surgery, a study was published entitled ‘Weight Loss Tongue Patch: An Alternative Nonsurgical Method To Aid in Weight Loss in Obese Patients’. In this paper, the developer of this oral device for weight loss reviewed eighty-one (81) patients who had the procedure performed over a four year period. The end point of the analysis was the amount of weight loss that had occurred at one month after its application. The average amount of weight loss achieved was just over 7 kgs. (about 15 lbs) with no significant complications encountered.

The tongue patch has shown that it can result in significant weight loss in the short term…or as long as it is in place. It was removed at one month after placement as it becomes harder to remove after that due to tissue ingrowth. The source of the weight loss is undoubtably being restricted to a liquid diet due to discomfort eating more solid foods. Part of its success is also keeping on a low calorie diet and doing regular exercise.

Jaw Wiring for Weight Loss Dr Barry Eppley IndianapolisThe tongue patch is very similar to a much older but equally effective minimal surgical weight loss approach…wiring your jaws together. Decades ago wiring your jaws together was a very effective method of short-term weight loss that also employed a liquid diet approach. The average amounts of weight loss sustained was also in the range of 10 to 15 lbs (and often more) in studies in which patients were clamped together for up to six weeks.

Dr. Barry Eppley

Indianapolis, Indiana

May 11th, 2014

Case Study: Extended Tummy Tuck in African-American Female

 

Indianapolis Tummy Tuck Surgery Dr Barry EppleyBackground: Tummy tucks are one of the most common and successful body contouring procedures for women. For those women that are willing to make the commitment to a major surgery, scar and recovery, it can be a near life transforming experience that  takes what diet and exercise can do to a whole new level.

Because pregnancy and weight loss affect all women, tummy tuck surgery is done on a very diverse population across all ages and races. But because of varying degrees of skin pigment and the need for a long incision, concerns abound about the potential scar in certain ethnicities. This raises the question of whether, for example, a tummy tuck for African-American women is done differently?

African-American skin, in general, does not heal that differently from skin with less pigment. However it is prone to a higher risk of hypertrophic or keloid scarring and hyperpigmentation, what one may perceive as a too enthusiastic response to scar formation and healing due to the thicker dermis and increased number of pigment cells. Thus one has to check how healing has occurred elsewhere. The simplest test for women is to see their c-section scar, which if it has healed uneventfully, indicates that a tummy tuck scar may do as well.

Case Study: This 35 year-old African-American female wanted to get rid of her loose abdominal skin and improve her waistline. She had two pregnancies and the second one caused a lot of stretch marks, loose skin and weight gain. Through aggressive dieting and exercise, she lost 60 lbs and was finally back to her pre-pregnancy weight but there remained considerable loose skin around her waistline and a lot of stretch marks. She felt she had reached the limit of what her own efforts could improve and she now sought tummy tuck surgery.

Extended Tummy Tuck results front view Dr Barry Eppley IndianapolisUnder general anesthesia, she had an extended tummy tuck due to the amount of loose skin. It was necessary to extend the excision beyond the traditional location (anterior hip points) of the ends of the tummy tuck so that redundant skin folds (dog ears) did not occur. Liposuction was done around the waistline into the flank regions to create a near circumferential waistline reshaping.

Extended TummyTuck results oblique view Dr Barry Eppley IndianapolisHer recovery was typical for a tummy tuck and a true full recovery with a return to strenuous activities took nearly six weeks. Of note is that her extended tummy tuck scar healed beautifully with only some slight hyperpigmentation. It healed in a fine line fashion without widening or abnormal scar thickening

Extended Tummy Tuck results side view Dr Barry Eppley IndianapolisOne of the major concerns in any cosmetic face or body procedure in African-Americans is the perceived risk of potential adverse scarring. (e.g., keloid formation) This would be extremely relevant in breast reduction/lifts and tummy tucks where great scar lengths are created. Just like this tummy tuck patient, I have never seen keloid scar formation in any African-American female in which I have performed the procedure. (over 100 cases in 20 years) The final scar looks normal although may have some degree of hyperpigmentation to it. Without a prior history of true keloid formation from a surgical incision or a cut, one should have no concerns that it will spontaneously occur from an elective aesthetic operation.

However, if one has developed abnormal scarring on their breasts or abdomen from previous surgery, a shorter scar tummy tuck should be planned. Such history is extremely important if the patient has skin excess on their flank areas which is going to require a longer tummy tuck scar to work out the excess skin (dog ears) which will inevitably occur from the elliptical horizontal tissue excisions.

Case Highlights:

1) Abdominal reshaping with a tummy tuck in African-American females is not associated with an increased incidence of abnormal scarring.

2)  The African-American tummy tuck has no other ethnic considerations other than wound closure and incisional management.

3) Tummy tuck surgery can cause an abdominal reshaping effect that goes far beyond what diet and exercise can do after one has reached a good weight.

Dr. Barry Eppley

Indianapolis, Indiana

May 10th, 2014

Plastic Surgery Wisdom – The Making Of An Expert

 

Plastic Surgery Wisdom Dr Barry Eppley IndianapolisAn expert is defined as someone who has skills and techniques in a particular field that is widely acknowledged as being an authority by their peers. One becomes an expert by acquiring extensive knowledge or abilities through education, training and experience that places them above that of an average practitioner in the same domain of endeavor. In essence, an expert has to acquire unique knowledge and then be recognized by others for having it.

While some can today circumvent the traditional process of becoming an expert by using marketing and the internet to become a self-proclaimed one, education and training is recognized as being key parts of earning that moniker. Knowledge alone, however, is not enough to make someone an expert. It is a good start and one can not become an expert without it, but the key factor that tips the balance to being an expert in any field is experience.

Experience always comes with age and the repetitive nature of doing a certain task. What experience ultimately provides is judgment…knowing when to apply one’s skills and then how to do it both efficiently  and effectively. As the old adage goes…‘good judgement is learned by initially making a lot of bad judgments’. In plastic surgery this means that one has generally had and seen most complications of any operation or in the treatment of any particular problem.

While many patients think they want a plastic surgeon who has had few complications or problems, that may only mean they have done too few operations.

‘An Expert In Plastic Surgery Means That Enough Operations Have Been Done to Have Encountered Most Of the Possible Complications’

Dr. Barry Eppley

Indianapolis, Indiana

May 7th, 2014

Fat Injections in the Hand for Raynaud Phenomenon

 

Fat Injections for Raynaud Dr Barry Eppley IndianapolisFor those who are afflicted with Raynaud phenomenon, the influence of cold weather on their hands or feet  is all too well known. It is estimated that up to 2% of the population has Raynaud phenomenon in varying degrees and amount of symptoms. This is seen as vasoconstriction of part or all of the digits in cold weather or any cold stimulation. This is to be differentiated from Raynaud disease (secondary Raynaud phenomenon) in which even more severe symptoms are seen in the face of an underlying autoimmune disease. (e.g., scleroderma or lupus)

There are numerous treatments for digital symptoms of Raynaud including surgical sympathectomies, oral agents such as calcium channel blockers and injectable Botox to name a few. But their effectiveness is varied and certainly not universal. Some patients fail to respond to any of them for any length of time. The success of fat grafting in the hand for cosmetic augmentation and in the treatment of wound healing problems of various etiologies raises the question of whether it might be similarly effective in decreasing Raynaud’ symptoms.

Fat Injections to Hands Dr Barry Eppley IndianapolisIn the May 2014 issue of Plastic and Reconstructive Surgery journal, an article addressing this potential treatment appeared entitled ‘Fat Grafting to the Hand in Patients with Raynaud Phenomenon: A Novel Therapeutic Modality’. In thirteen patients (21 hands) with Raynaud phenomenon and Raynaud disease, processed abdominal fat was injected into the dorsum of the hands as well as into the volar webspaces. An average of 30mls of fat was injected per hand. Patients underwent before and after injection laser speckle imaging. The fat injections resulted decreased pain, less cold-related attacks, improved skin texture and healing of ulcerations in most treated patients. Three patients (23%) failed to have any symptom improvement. Laser speckle imaging was inconsistent and showed increased blood flow in less than half of the hands that were tested.

While hand fat injections did not help every patient, enough were improved to indicate that the addition of fat can be added to the list of Raynaud treatments. It is not yet understood how fat may help in this condition. Plausible mechanisms include the addition of soft tissue volume which increases overall hand perfusion, the influence of stem cells on ischemic tissue or some combination to both. Regardless of mechanism, fat is a safe, natural and well recognized procedure with no side effects other than requiring a minor surgical procedure.

Dr. Barry Eppley

Indianapolis, Indiana

May 7th, 2014

Submental Neck Fat Reduction by Injection – Clinical Trial Results of ATX-101

 

Since the days of Lipodissolve, which was a rage in the early 2000s, the search for an injectable fat dissolving drug  has been ongoing. Taking one of the original compounds used in Lipodissolve, deoxycholic acid (DCA), Kythera has been doing clinical trials for its injectable drug ATX-101. This is a purified synthetic version of DCA which helps break down fat. They have been studying it for the specific application of the reduction of neck (submental) fat.

ATX-101 Submental Fat InjectionsAt the recent annual meeting of the American Society of Aesthetic Plastic Surgery, Kythera presented findings from its Phase III clinical trial. Pooling all patients in their trials, around 80% of the patients treated with ATX-101 showed a visible improvement in their submental area (contour reduction) after four treatments regardless of age, gender, race and body mass index. The positive responder s felt they looked thinner and more youthful. Mild adverse events occurred as is expected with these treatments including temporary discomfort, swelling and bruising at the neck injection sites. These events were not severe for the vast majority of patients to discontinue treatments. (less than 2% did)

These clinical results follow what I observed years ago with the old Lipodissolve injections. While its effects do not rival what one could achieve with liposuction, they offer a non-surgical method of achieving a 25% to 50% comparative effect in my experience. For the properly selected patient, this can avoid the surgical process and associated downtime which can be very appealing.

Injectable Submental Neck fat Reduction Dr Barry Eppley IndianapolisOne reality of these treatments is that its effects do not come with just a single injection session. Its best effects are seen by doing an injection series which numbers four in this study. Usually spaced out weeks apart, it takes several months to show their full effects. Each injection session is associated with visible swelling which takes about a week to go down. When factored over the months of injection sessions, this amounts to almost a week of ‘recovery’ from the treatments. These considerations must be considered when comparing it to surgical liposuction.

Dr. Barry Eppley

Indianapolis, Indiana

May 5th, 2014

Fat Compartments in the Neck – Implications for Neck Contouring Surgery

 

Neck Fat Removal Dr Barry Eppley IndianapolisFat in the neck is one of the major contributors to its shape. Large amounts of fat create full and/or droopy necks and work against a pleasing neck angle and profile. As a result, the removal of fat is part of just about every neck contouring procedure from liposuction to necklifts. The neck is usually defatted by liposuction at the supraplatysmal level but may also undergo direct excision at the subplastymal level in other neck contouring operations. (e.g., submentoplasty)

In the quest for optimal neck contouring and maximal fat removal, it is helpful to know where the fat compartments are in the neck and their contributions to the overall fat volume. This would help to understand what type of neck changes can be done and what procedures may be needed to fo them.

Neck Fat Compartments Dr Barry Eppley IndianapolisIn the May 2014 issue of the Aesthetic Surgery Journal, a study was published entitled ‘ Defining the Fat Compartments in the Neck – A Cadaveric Study’. In this study the anatomic compartments of the neck and their quantity and relationships were evaluated in cadaver heads by dissection. Supraplatysmal fat was found between the skin and the platysma muscle, and it was divided into suprahyoid and infrahyoid fat. Subplatysmal fat was found deep to the platysma and between the inner edges of the anterior digastric in the midline ad was also divided into suprahyoid and infrahyoid compartments. Lastly, the very deep fat below the anterior digastric muscles was identified as its own compartment.

Their findings shows that roughly 50% of the fat in the neck was in the supraplastysmal space. The subplatysmal fat accounted for roughly 25% and the remaining 25% was around the submandibular gland. The very deep fat was minute, accounting for only 1% of all neck fat.

Submentoplasty Dr Barry Eppley IndianapolisWhat this study shows is that the most commonly treated area of the neck for fat removal done by liposuction is the supraplatysmal space…and this accounts for only half of all neck fat. This means that many patients may not be able to achieve optimal neck contours with liposuction alone. In some cases the subplatysmal neck fat needs to be removed for a more significant neck contour improvement.

Dr. Barry Eppley

Indianapolis, Indiana

May 4th, 2014

Umbilical Reconstruction in Tummy Tuck Surgery

 

Umbilicus (Belly Button) Indianapolis Dr Barry EppleyEver since the 1950s and the beginning of the evolution of the modern day tummy tuck, the search for techniques that produce a natural looking umbilicus have been both varied and different amongst many plastic surgeons. Everyone recognizes that complete loss of the umbilicus is associated with emotional disturbance in most patients even though it serves no medical function other than being recognized as being human.

The techniques for umbilical reconstruction (umbilicoplasty) are varied but most, historically, focus on preserving the original umbilical stalk. Known as umbilical translocation, the original stalk is preserved and then brought back through a new position on the abdominal skin. While the abdominal skin has been lowered, the new umbilical position is actually the same as the old one based on its original horizontal and vertical axis location. This creates a fine line scar around the skin on the outside but it really is the same umbilical stalk and in exactly the same position. It may have been shortened and reshaped but it is the original umbilicus.

Umbilical Translocation in Tummy Tuck Indianapolis Dr Barry Eppley Umbilical Translocation in Tummy Tuck result Dr Barry Eppley IndianapolisThe problem with the umbilical transposition technique is that it usually leaves visible scars around the outside with a color difference from that of the surrounding abdominal skin. Suture marks may occur and, if the incision lines separate during healing, hypertrophic scars can develop and significant umbilical narrowing (stenosis) may result.

Umbilical Reconstruction in Tummy Tuck Dr Barry Eppley IndianapolisAn improved approach to the umbilicoplasty part of a tummy tuck is to use a reconstructive approach. The original umbilical stalk is discarded and the new one is made from the outer abdominal skin. These have been described as either a three or four skin flap technique using an outer ‘Mercedes’ or star-shaped skin incision. These skin flaps are turned inward and sewn to the abdominal aponeurosis in the midline. This hides the scars within the umbilicus which makes them imperceptible or creating natural pleats.  The skin color matches perfectly to the outer abdominal skin. Even if wound separation of the skin flaps occur, any contracted scar will form inside the umbilicus pulling it in even deeper.

The umbilicoplasty part of a tummy tuck, while the smallest step in the overall operation, is given great significance for most patients because it is more visible than the lower tummy tuck scar. Most umbilicoplasties are performed by a translocation technique rather than a reconstructive one. Umbilical reconstruction is more effective at avoiding visible and hypertrophic scars and obvious pigmentation differences between the remaining umbilical stalk and the outer abdominal skin. Pulling abdominal skin inward to create the new umbilicus avoids all the problems of the translocation technique with the creation of sufficient depth and some amount of superior hooding.

Dr. Barry Eppley

Indianapolis, Indiana

May 4th, 2014

The Current Futility of Stretch Mark Therapies

 

Stretch marks Dr Barry Eppley IndianapolisStretch marks are an aesthetic bane for many people, particularly women. Often occurring after puberty, pregnancy and weight gain/loss, the development of white or red depressed lines is distressing and they will be present forever as they never improve on their own. Many treatments allege to improve or remove stretch marks but the sheer number of treatments available over the years indicates the few if any are effective at doing so.

But what makes stretch marks such a difficult aesthetic problem to improve? To understand the why, it is important to look at the histology of stretch marks which are anatomically described as Striae Distensae. Technically there are two distinct forms of striae distensae, striae rubrae and striae albae. By histologic assessment, normal skin has haphazardly arranged small collagen fibers and thin elastin fibers in the papillary dermis, surrounded by ground substance; coarse elastic fibers and thick bundles of collagen parallel to the direction on the skin in the reticular dermis.

In contrast, striae rubae (red stretch marks) are tense, red and erythematous and they histologically show fine elastic fibers in the dermis with thicker tortuous fibers in the periphery. There is a reduction and reorganization of elastin fibers and structural changes in collagen are seen. Striae albae (white or pale stretch marks)  appear pale, depressed and wrinkled. Their histology demonstrates epidermal atrophy and loss of the rete ridges and densely packed thin collagen bundles are arranged horizontally, parallel to the surface of the skin in a similar way to in a scar.

These histologic findings show that stretch marks are distinctly different from normal skin. Their collagen infrastructure is drastically changed to thinner less oriented collagen layers with fewer elastic fibers. This is well known by their depressed and indented external surface lines. Trying to change this weakened and thinner collagen by any type of topical cream or treatment, while theoretically appealing and makes for robust retail product sales, is fundamentally flawed and not possible. You simply can’t thicken the damaged collagen structure of the skin. No clinical study has ever been published that supports any sustained effectiveness for topical therapies for stretch marks.

Can more invasive treatments, like laser resurfacing, laser collagen stimulation or an internal approach like Cellulaze, be effective? At the least they can have a more profound effect on the skin’s collagen infrastructure. Other than reducing redness from striae rubae, external or internal laser efforts not been shown to be effective either.

Stretch mark therapy today remains largely ineffective. The changes to the skin’s structure remains permanently changed and irreversible…at least by today’s technology.

Dr. Barry Eppley

Indianapolis, Indiana

May 4th, 2014

Surgical Techniques in Cheek Dimpleplasty

 

Cheek Dimple Surgery Dr Barry Eppley IndianapolisCheek dimples are natural indentations some people have when they smile. Although some people have them naturally when they are not smiling and they merely become deeper when they do. The aesthetics of cheek dimples are personal, some like them and want them placed and a few others have them wand want them reduced/removed.

The anatomic basis of cheek dimples has been shown to be a defect or diastasis in the muscle layer between the skin and the buccal mucosal lining of the mouth. This is demonstrated by how a dimple deepens when one smiles. Depending upon the location on the cheek, this could involve the zygomaticus or buccinator facial muscles. Although this does not fully explain why one can have a cheek dimple without any facial animation, indicating that there must be a fat defect as well in some patients.

The surgical creation of a cheek dimple, often called a cheek dimpleplasty, does not have a standard technique. It is still a relatively uncommon procedure done by just a few plastic surgeons. How to effectively create a cheek dimple, and then have it maintained, varies amongst different surgeons.

Cheek Dimple Muscle Surgery Technique Dr Barry Eppley IndianapolisIn the March 2014 issue of the Annals of Plastic Surgery, an article entitled ‘Transoral Buccinator-Pexy (TBP)’ was published that details out a method of creating cheek dimples. In this method, the cheek dimple point is marked out about 2 cms above the corner of the mouth on its course to the lateral canthus. Under local anesthesia, a needle is passed through the skin and into the mouth through the buccal mucosa. The key manuever is to avoid the location and course of the parotid duct. Using the needle as a guide, a tissue punch is used to remove a piece of buccal mucosa down to the muscle. The needle is then used to thread a suture back out to the skin, the needle is removed, a bite of the dermis is taken and the suture passed back into the mouth where it is tied down to create the desired depth of the dimple. Their series of patients had successful results with no complications. As is common the cheek dimples because less pronounced as the swelling subsided and only appeared with smiling.

The authors chose to call their cheek dimple procedure a transoral buccinator-pexy, which  is an anatomic description of what is actually done. This technique is remarkably similar to the cheek dimple creation technique that I have evolved to over the years. I still refrain from using a permanent suture having had a few infections and extrusions from a permanent suture. This is a risk when a permanent suture is placed into the dermis of the skin. I have found good success even using a 4-0 plain suture on a straight needle.

Regardless of these suture nuances, this technique of cheek dimpleplasty is a very safe and effective one that can be done successfully under local anesthesia.

Dr. Barry Eppley

Indianapolis, Indiana


Dr. Barry EppleyDr. Barry Eppley

Dr. Barry Eppley is an extensively trained plastic and cosmetic surgeon with more than 20 years of surgical experience. He is both a licensed physician and dentist as well as double board-certified in both Plastic and Reconstructive Surgery and Oral and Maxillofacial Surgery. This training allows him to perform the most complex surgical procedures from cosmetic changes to the face and body to craniofacial surgery. Dr. Eppley has made extensive contributions to plastic surgery starting with the development of several advanced surgical techniques. He is a revered author, lecturer and educator in the field of plastic and cosmetic surgery.

Read More


Free Plastic Surgery Consultation

*required fields



Pricing

The cost of any type of elective plastic surgery plays a major role in the decision to undergo the procedure(s).

Get Your Quote Here


My Plastic Surgery Story

Military Discount

We offer discounts on plastic surgery to our United States Armed Forces.

Find Out Your Benefits


Categories