The thickness of the patient's skin is a critical factor in deciding whether a blunt cannula or needle PDO threads are to be used
Medical aesthetics is a rapidly advancing field and is becoming increasingly popular with patients, many of whom are requesting non-surgical procedures.
In fact, new research shows that, while demand for surgery has decreased, especially after the ‘PIP’ breast implants scandal (Hegyi, 2019), non-surgical treatments are booming. This industry could be worth £3 billion by 2022 (Buisson, 2018).
The head, neck and other parts of the body are amenable to treatments, and results are very satisfactory when performed by properly trained, qualified and experienced medical aesthetic clinicians.
However, there is one part of the body that is difficult to treat, and yet, is the part that shows one's age to the world: the neck, which is an area usually not covered by clothing.
Depictions of the neck
A youthful, smooth, blemish-free neck enhances the beauty and aesthetic appeal of the individual in both men and women.
During the time of the Pharaohs in Egypt, Queen Nefertiti was renowned for her beauty. Images of her portray her with a long, smooth and slender neck. Today, the neck is a part of the body that many of patients want treated.
For these reasons, a plethora of clinical modalities are available to treat this area, including lasers, thermal technologies, skincare treatments, botulinum toxins, dermal fillers and tissue-lifting threads.
Tissue-lifting threads made of polydioxanone (PDO) for treating the neck are the subject of this clinical paper.
Current methods and a new technique
The majority of present techniques for treating the neck use cannula-type cog threads that have either blunt or sharp needles. There are also non-cog smaller skin rejuvenation threads, which can be used either as a standalone treatment or in combination with the cog thread.
The author's ‘half-wave’ technique for inserting needle threads will be described in detail. The author believes that this technique, though requiring a good degree of expertise, achieves a better clinical outcome than other thread techniques.
The ‘half-wave’ needle advancement technique is a new procedure designed to put patient safety first. It allows sharp-cutting needles to be inserted in anatomically hazardous areas such as the face and neck. In these areas, simply inserting and advancing the needle through the tissues can result in cutting and damaging important structures.
For example, in the neck, neck-lifting procedures can result in cutting the cervical branch of the facial nerve, the external jugular vein, the anterior jugular vein, the branches of the cervical plexus or the cervical lymph nodes, as well as trauma to other deeper structures. These include damage to the sternocleidomastoid muscle and the muscles attached to the hyoid bone in the submental area.
Using needles
A reasonable question to ask is that if using a needle thread is so fraught with danger, why use it when you could continue using the much safer blunt-ended cannula threads for tissue lifting?
The answer lies in the improved clinical outcomes and greater tissue-lifting capacity, which leads to greater patient satisfaction. Methods using PDO threads with blunt-ended cannulae give mixed results, but this raises the question of how and why this is the case.
After performing hundreds of thread procedures using PDO blunt-ended threads, clinical audit showed that many patients had unsatisfactory results with their neck lifts. It was observed that the incidence of relapse and return of neck lift ptosis occurred in many cases after just a few weeks of the procedure. The result was good initially, but then rapidly deteriorated.
In fact, some researchers concluded that these types of procedures should be limited for patients who had contraindications for surgery and should be abandoned in all others who did not fit this criteria (Bertossi et al, 2019).
This poor longevity resulted in many practitioners losing confidence in PDO neck-lifting threads and many stopped performing these procedures.
PDO is a material hydrolysed after approximately 200 days in the body, but patients were getting relapse even after as little as 2 weeks.
After careful consideration and observation of the relevant factors to determine the cause some conclusions were drawn.
Reasons for poor longevity
PDO-type cogs used for a maxillary and mandibular lift appeared to give lasting results for up to 12 months—so, this raises the question of why it was not doing the same in the neck.
The anatomical and functional differences between the face and the neck revealed some clear relevant factors that may offer an explanation.
The surface area of the neck is large when compared to the face. This means more tissue has to be lifted. Despite its smaller overall surface area, the skin of the face does not have the same degree of laxity present in the neck. This may be due to anatomical differences.
There are ligaments present in the face that are not present in the neck. True facial ligaments such as the zygomatic and mandibular-retaining ligaments and false ligaments such as the masseteric ligament help to hold the facial skin and facial fat pads in place. The facial fat pads also have inter-lobular ligaments that help in retaining fat pad positioning. With age, this effect diminishes, allowing caudal fat pad migration.
In the neck, skin thickness, the amount of subcutaneous adiposity, the number of fibres of the banded platysma muscle and the size of the neck itself are variable with body type and age, and also varies between the sexes.
Some relevant clinical observations must be performed to eliminate neck pathology, such as thyroid disease (goitre), parathyroid disease and neck mitotic pathology, including checking for cervical lymphadenopathy as a minimum prior to any lifting procedure.
» [This technique] allows the aesthetic clinician to achieve a greater degree of tissue lifting, especially in the neck, and improves the vectors and the final aesthetic result «
Provided the clinical examination is satisfactory, the neck morphology and skin laxity must be examined to check if thread lifting is suitable. The thickness of the patient's skin is a critical factor in deciding whether a blunt cannula or needle PDO threads are to be used. This is of relevance as the needle threads require engagement in the superficial musculoaponeurotic system (SMAS), as described later.
Another important determining factor in deciding whether a needle or blunt cannula is to be used is the range of movements possible with the neck. These are far greater in magnitude and direction than those possible with the face. Even the biggest smile or the widest mouth opening cannot match the range and size of the dynamic arc of movements possible with the neck.
The failure of neck lifting procedures using PDO-cog cannula threads may simply have been a result of the cogs becoming disengaged, allowing the neck tissues to slip back due to these factors. The number of cogs that are available for skin engagement is also important. A more secure thread tissue engagement procedure was needed.
Cannula threads are blunt-ended and pass through the tissues by traversing the line of least resistance. They do not cut the tissues, but simply separate the various skin layers. The cogs engage this tissue, but being small, this engagement is easily overcome, especially in the neck due to the factors previously mentioned. A solution was needed that not only allowed the cogs to engage, but a technique that was able to take and hold ‘bites’ of the tissues similar to a sewing needle, which holds the cloth in small sections. This is only possible with a needle-ended thread.
A blunt cannula will not ‘cut through’ tissue, nor grip it and, by its very nature, traverses the tissues, as previously stated with no cutting action.
Needle dangers
The dangers of using needles are obvious: the neck is possibly the worst area of the body to be treated using needles.
Theoretically, it is possible that during thread placement using a needle in the neck, the patient or clinician may move or sneeze, resulting in the needle ‘diving’ into the neck and puncturing, for example, the carotid artery, carotid sinus, external jugular vein or the thyroid gland, to name but a few.
This could result in severe damage to these structures, or even be fatal. These are extreme scenarios, but they illustrate the point.
As the neck contains many important structures needed for life, it is not surprising that predators such as the big cats target this area when hunting prey. It is the only part of the body where life-sustaining structures are very near the surface and easily damaged with the large bite force and long canine teeth of predators.
Half-wave technique
The half-wave technique is a method developed by the author to achieve better cog engagement, thereby improving tissue-lifting ability. The technique is designed primarily to put patient safety first.
In clinical practice it has given very good results and the neck lifts performed appear to be holding up well, but long-term results are not available as the technique is new. At the time of writing, the longest neck-liftings done are holding up well after 5 months in place.
Certainly, the drop and return to neck ptosis has not been seen in the few number of patients who have had neck lifts with this technique.
Procedure
Let us assume that a wave, for our purposes, consists of a base, an ascending and descending portion and a crest (Figure 1). Let us also assume that the anatomical structures we are trying to avoid are below the base (Figure 2). The needle, starting from the base at the ascending arm of the wave is advanced only in the direction of the ascent to the crest. The needle is then dropped vertically to the base without advancement. The procedure is repeated so that the needle advances through the tissues (Figure 3).
Figure 1. The normal wave 
Figure 2. Needle advancement trajectory 
Figure 3. Multiple half-wave advancement
It can be seen that each needle advancement results in approximately half of the wave length. This technique achieves all the desired objectives. It advances the needle, takes a cutting grip of the tissues and protects important anatomical structures.
Conclusion
The half-wave needle advancement technique is a new procedure developed to overcome the problems of treating the neck using PDO-cog or other threads, and appears to achieve very satisfactory clinical outcomes.
It allows the aesthetic clinician to achieve a greater degree of tissue lifting, especially in the neck, and improves the vectors and the final aesthetic result.
It is only possible by using needle-ended threads that are able to cut into the SMAS, deeply engaging the cogs and the shaft of the thread within it, rather than taking the line of least resistance that occurs when cannula threads are used.
This type of thread placement, coupled with a greater number of cogs, appears to give more satisfactory results than other thread-lifting methods currently in use.