In the first of a two-part article, Dr lrfan Mian explains what practitioners should be aware of when placing PDO cog threads to ensure patient safety and positive results
Polydioxanone (PDO) as a material for lifting tissue is now recognised as a relatively safe product with transient minor side effects, provided correct operative techniques are adopted. This is supported by a 24-month retrospective study of PDO threadlift outcomes by Suh et al. that took place in 2015.1
The outcome of any threadlift procedure is dependent on patient selection, using the typical exclusion criteria that would also be used for the placement of dermal fillers and botulinum toxins. Therefore, it will not be listed in this article. There are, however, some additional criteria specifically related to the art and science of PDO thread placement. In practical terms, PDO threads can be divided into two main types: cog threads and non-cog threads.
I have observed that the lack of additional staff has contributed to the failure or poor clinical outcomes of some of these procedures
Cog threads are barbed and are available as unidirectional, multidirectional, 3D or 4D barbs.2 Cog thread placement requires a degree of clinical acumen, treatment planning, manual dexterity and a good aseptic technique. I shall highlight the important points to be aware of when conducting a cog PDO thread treatment, which are paramount in achieving consistently good clinical outcomes.
Although the focus of this article is on cog threads, there are also non-cog PDO threads which are available as monos, twisted monos, tight and normal pitch screws, multifilament and cavern threads. They come in a variety of sizes and may be sharp or blunt ended. These types of PDO threads tend to be more ‘forgiving’ as they hydrolyse after four to eight weeks, compared to nine to ten months for cogs. The exception is caverns, which are thicker and last much longer, between four to five months.
Cog placement to rejuvenate the face and submental area can be a challenge. I believe this type of procedure is probably not suitable for a ‘sole practitioner’ to carry out as, in my experience, clinical outcomes are greatly improved if there are suitably trained and qualified staff present to assist the operating practitioner.
My experience over the last few years has highlighted the need for a team approach during the placement of PDO threads. I have observed that the lack of additional staff has contributed to the failure or poor clinical outcomes of some of these procedures. It is difficult for a sole practitioner to simultaneously do a great deal of multitasking to achieve good thread placement.
The practitioner is required to place a number of cogs, in some cases ten or more, and hold them in place, tense them and adjust the tension as required in order to achieve symmetry, which necessitates looking at the patient’s face front-on. At the same time, the threads must be held in position, twisted in opposite directions, tension checked again, followed by the placement of additional threads to achieve ‘thread locking’. In some cases, the practitioner is supported by two other members of staff, thereby performing a six-handed threadlift.
Finally, whilst all is held in place, the threads have to be ‘deep tissue’ cut. This technique involves placing the thread between the blades of the scissors and then pushing the skin down with the scissors before cutting, which ensures the skin bounces back and completely covers the thread. If the thread is left too superficial, there is risk of infection and poor healing, which, at worst, could result in a granuloma.3
Cog placement is not a pain-free procedure and local anaesthesia for the face, neck and body can be used to achieve patient comfort, which may include facial and body infiltration or block anaesthesia. In addition, the practitioner may choose to employ a method I created, the Mian’s Alternative Snooker Hold (MASH) technique, which allows for ‘on demand’ anaesthesia at the appropriate site at the request of the patient. This is done by inserting the PDO thread into a 2ml syringe, which has been prefilled with local anaesthetic without a vasoconstrictor.4
Intravenous conscious sedation must be carried out in appropriately-equipped premises for resuscitation and recovery, with staff who are trained and experienced in resuscitation and patient recovery procedures
Some practitioners use and recommend intravenous conscious sedation using titrated midazolam, supplemented with local block or infiltrative anaesthesia. Cosmetic surgeon Dr Rakesh Kalra advocates in his study ‘Use of barbed threads in facial rejuvenation’ in the Indian Journal of Plastic Surgery, in 2008, that this is the best way to perform cog thread insertion.5 I believe this is likely to be because, apart from achieving greater patient comfort, there is subsequent patient amnesia which improves the patient experience as they are unaware of the pain.5 In my experience, this results in greater patient retention and a higher rate of uptake of re-treatment. Intravenous conscious sedation must be carried out in appropriately-equipped premises for resuscitation and recovery, with staff who are trained and experienced in resuscitation and patient recovery procedures.
The practitioner can use a variety of infiltration anaesthetic sites and there are a number of vasoconstrictors available based on personal preference. The patient’s medical history, however, may necessitate a particular agent. An example would be a patient with a history of cardiovascular disease, such as exertional angina, which is under control with medication. In this case, it would be unwise to use adrenaline as a vasoconstrictor as it may, by adding to endogenous adrenaline, cause syncope or even a cardiac-related emergency. Other vasoconstrictors such as felypressin, which are not cardiac stimulants, should be used instead.
Care should always be taken when using adrenaline-based vasoconstrictor local anaesthetic, as I have experienced cases where a cardiac event has occurred even though the patient’s medical history was stated as clear. It was subsequently found that these patients had subclinical asymptomatic cardiac disease.
Cog placement can cause significant transient commensal and pathogenic bacteria to enter the tissues and, more importantly, enter the circulatory or lymphatic systems, which will carry the infection away from the operating site. These ‘infection emboli’ may then lodge anywhere in the body. This may include the tricuspid or mitral valve of the heart if they have sustained previous damage by, for example, rheumatic fever.6
In most cases the patient would state they have had rheumatic fever, which usually presents as a childhood fever, in their medical history. Many patients may be aware or have been informed that they have a cardiac murmur or a systolic or diastolic thrill as a result. These patients would be given antibiotics pre-procedure.
In other cases, the patient may be unaware that they had rheumatic fever as they have suffered no clinical side effects. They may have assumed that they simply had a ‘childhood fever’. These patients may be at risk of streptococcal bacterial colonisation of the cardiac valves, which subsequently may release bacterial emboli, resulting in the symptoms of subacute bacterial endocarditis (SBE), which could have a debilitating or even fatal outcome.6
For this reason, prophylactic antibiotic cover must be given. This can be either as a course prior to the appointment for cog thread insertion or as an oral bolus one hour before treatment, followed by an oral course six hours post procedure, for up to five days. The important point is that at the time of the threadlift procedure, there should be adequate therapeutic levels of the appropriate antibiotic in the tissues of the body.
One of the main causes of an unsuccessful cog treatment is the placement of the cogs in the wrong tissue plane. The correct plane for insertion is the superficial musculo-aponeurotic system (SMAS) and the technique for placement has been described and well documented.7 A new and relatively easy method to find the correct plane is by the use of a 2ml syringe that I have created and written about in a previous article entitled ‘PDO threadlifting’, published in the Aesthetics journal in 2016.4
It is important for practitioners to be familiar with the anatomy of the SMAS, especially its centrifugal arrangement in the face and neck. The SMAS is not uniformly found over the face and neck and in some areas, such as the forehead, lower face and neck, it combines the facial muscles, especially the ‘frontal’ part of the occipitofrontalis, and the mandibular portion of the platysma muscle.8
Some PDO cogs are available with a needle-type end which certain practitioners find easier to insert as an entry point does not have to be created. Needle-type PDO cogs, however, have a far greater propensity to damage and cut vessels and nerves. This can cause post-treatment numbness or paralysis of the affected mimic muscles.
The facial artery is also at risk of puncture with these types of threads, especially at its most superficial point near the oral commissure, also known as Manson’s point. This point is a surgical landmark near the corners of the mouth which identifies the facial artery with 100% accuracy.9
Hard evidence-based research regarding techniques, effects, results and long-term outcomes is limited for all types of thread techniques due to it still being a relatively new procedure.
Therefore, to advance our knowledge, an exchange of ideas and case studies between threadlift practitioners may result in better outcomes. It is this empirical experience which is important in the advancement and understanding of PDO thread therapy.
Read part two of this article in the next issue of Aesthetics.