In the search for less invasive procedures to treat the signs of facial ageing, thread tightening has become increasingly popular, although results do not always meet patients expectations, especially in terms of duration. Characteristics of ageing of the face are described, to try to understand how the structures are involved and can be treated. The different types of threads are described, with their drawbacks and complications. The author’s preferred choice is explained, and some results are presented.
Why use suspending threads? For a long time physicians tried to treat the signs of facial ageing1 at a time when surgery was quite a perilous adventure. The results were interesting but often not very long-lasting and the quality of results would appear grossly insufficient nowadays. Advances in anaesthesia and surgical procedures have led to better and longer-lasting results, with increased safety in surgical face-lifting techniques. But drawbacks, like post-operative downtime over the demand for a fast recovery, have triggered a search for less invasive means, and for the last 20 years we have seen a return to the use of suspending threads. A greater knowledge of ageing mechanisms in the face allow for a better understanding of which structures should be treated and how they should be treated, in order to obtain longer lasting results.
Characteristics of the ageing face
In contradiction to what was previously thought, facial muscles do not seem to relax with ageing, but stay gradually in a state of permanent contracture2. This contracture displaces the deep sub-orbicularis oculi fat (SOOF) which leads to the movement of the more superficial fat3 from the compartments described by Rohrich and Pessa4. These compartments are just below the superficial muscular aponeurotic system (SMAS), which is the facial equivalent of the fascia superficialis in the other areas of the body. The fascia superficialis is the border between the subdermal, superficial fat, and the deepest zones of fat. This is quite important, as it explains why the superficial, subdermal fat, is not directly involved in the process of ageing. As in the rest of the body, the subdermal fat changes only when body weight changes5.
This sliding is allowed by the loose interface between the SMAS and the fat structures, to facilitate normal gliding muscular movements, and is only stopped by the ligamentous and fibrous retaining structures6, resulting in apparent deepening of the nasolabial fold (medial cheek fat) and marionette lines (jowl compartment)7, 8.
SMAS itself does not slide as it is firmly attached to the underlying structures — mimic muscles and bone — via retaining ligaments.
The midface skin is well attached to the malar fat pad, the nasolabial and the jowl fat, thus their elevation is very effective in restoring youthful appearance3, 9, and their repositioning does not disrupt the ligaments, maintaining a normal appearance.
It appears that the proper aim for suspending threads would be repositioning of the displaced fat, as this will produce a more physiological and natural result than direct tensioning of the skin.
In this respect, threads should be able to hold fast in these fairly soft and fragile tissues. We can therefore make a distinction between the anchoring zone, i.e. area to be displaced for positioning, and the fixation zone, i.e. a fixed point to hold and maintain the new position.
Different type of threads
The first threads to be used were the most readily available threads: silk, gold, horsehair or catgut. They were used either to create a subcutaneous loop or a net by a criss-crossing technique.
The net or criss-crossing technique consists of insertion of several parallel rows of threads, either resorbable or not, placed in similar rows perpendicularly to the initial one.
The inflammatory, foreign body reaction induced will result in a thickening of the skin, hence an appearance of tightening. Silk was particularly prone to inflammation and led to many complications, infections or granuloma formation as understood many years later by Akiyama et al10. This was revived a few years ago with the widely publicised gold threads, with the same sort of results and drawbacks. More recently practices have used resorbable threads directly mounted on needles of various lengths, often called ‘Korean Threads’, with or without cogs, to create this foreign body reaction often designed as ‘collagen stimulation’. It seems that this collagen is mainly type III, immature, and is the first to appear as a quick means to protect the organism against the introduction of any recognised foreign substance, leading to fibrosis11, 12. These threads can be inserted either superficially, in the fibrillar dermis, or deeper, in the SMAS or even in the muscles13. This positioning seems to be either too superficial, with the risk of granulomatous foreign body reaction, or too deep, with the risk of facial nerve or muscular impairment.
Loops gave good results, but were not long-lasting, as the weight and movements of the facial tissues gradually make them slide through the loop, described as the ‘cheese wire’ effect.
The loop technique was revived in the 1970s under the name of curl lift. The insertion was made through a skin incision, in the temple, pre-auricular or retro-auricular area. After passing the long needle with a thread along the determined path, both ends are tied together within a fascia to give a strong attachment. It gave the same interesting results as with the original technique, but unfortunately, in thick or heavy faces, fairly short-lasting results.
It is now mainly used in association with a surgical facelift, in order to minimise the drawbacks of the procedure: for suspension of the malar fat pad during a facelift procedure by mattress sutures suspended to the superficial temporal fascia9 or as two or three loops positioned to lift and maintain the posterior, middle and anterior zones of the cheek14–16
Kestemont17 noted that, from analysis of opaque clips positioned along the SMAS plication lines, results do not seem as feasible as one would expect in terms of duration, confirming the ‘cheese wire’ effect of simple suture threads within the soft tissues of the face.
The use of threads larger than simple sutures proved to be more efficient, as described by Yousif et al3. They used expanded polytetrafluoroethylene (Gore-Tex®, MycroMesh®, W.L. Gore & Associates, Inc., AZ, US). But these needed to be inserted during an extensive deep facial dissection and fixed to a mini anchor in the frontomaxillary process of the orbital rim. A less invasive technique is still quite far away yet, but it allows for pointing out that anchoring has to be strong — it is the key to repositioning the tissues, and fixation has to be on a fixed, immobile point to maintain the results18–20.
Some wider threads like Elasticum are used in a similar fashion: inserted as a complete loop around the cheek or neck, tied to itself through a limited skin incision, as a minimally invasive surgical procedure21.
Then came what can be called the first revolution: barbed sutures22. APTOS threads were the first barbed suture to be commercialised, and for the first time the idea was to place the anchoring over the entire length of the thread. As with many new ideas, it became very popular, and started to be widely used. Many other brands are available: unidirectional or bidirectional, looped, resorbable or permanent. Clinically, some results proved to be somewhat disappointing, with asymmetries, short lasting results, and breaking of the threads. Helling et al23 stated that ‘barbed sutures clinically seem to provide little traction on tissue after 1 month of healing.’
In a study on cadaver faces, Sasaki et al showed that holding tension, slippage tension and pull-out tension were significantly lower with straight barbed sutures in comparison to looped ones20,24.
As it is the case with simple sutures, Cog threads are used as an adjuvant to surgical procedures, either to tighten the SMAS, help reposition the tissues or close the wounds25. See also Mataraso and other authors in the specially dedicated supplement of Aesthetic Surgery Journal26.
Searching for a better anchorage, Isse27 had the idea of inserting resorbable cones between retaining knots on a polypropylene suture. The insertion was made through a skin incision within the temporal area, in order to suture the free end to the temporalis fascia for a strong attachment. The important surface of anchoring proved stable and efficient, to the extent that the threads could be retightened after 2 or 3 years28. These holding capacities had already been described by Sasaki in 200820. Silhouette threads were used for tightening other areas of the body, such as the gluteus29, but they need to be inserted through an opening in the skin with suturing to a strong fascia.
Since 2011, these have been commercialised as the Silhouette Soft® threads, bidirectional and made of totally resorbable Poly-L-Lactic acid thread and cones (Silhouette Lift S.L., Barcelona, Spain. Silhouette Lift Inc., Irvine, CA) (Figure 1).
After being taught by Dr Pierre Fournier how to use the curl-lift technique in the 80s, and being involved in the first use of Aptos Threads in France 30,31, and being disappointed by the duration of the results, the author started with Silhouette Lift™ mini invasive technique in 2008.
The author experienced fair results in the face, and the ability to retighten proved helpful and efficient when skin and fat had begun to slide again after 18 to 24 months (Figure 2).
When Silhouette Soft was introduced in 2011, it required no surgical procedure. The simplicity and ease of the insertion and positioning was a real advantage, it offered the same safety and holding, but with less tension applied. Instead of pulling all the facial tissues upward, the bidirectional orientation of the cones (there are either 4, 6 or 8 on each side), allows for less weight, thus less tension, applied to the cones. The tissues are concentrated between the ‘anchoring’ end and the ‘holding’ one, so their use is not only in repositioning the soft tissues, but also in restoring volume (Figure 3).
The most important point to place correctly is the most distal cone, as this is where the maximum effect of repositioning is needed. The thread is introduced through a hole made with an 18 G needle, perpendicularly to the skin surface, at a depth of approximately 5 mm, 5 cm from the exit point. The first needle is introduced through the hole, and pushed in the subcutaneous fat layer until it exits, about 1 cm further than the wanted most distal cone.
Figure 4A illustrates how to introduce the needles in the very same hole. The second needle follows the first and is introduced via the same hole, making quite sure not to create a bridge in the tissues to prevent puckering of the skin. The needle should then be inserted into the second half (Figure 4B). The needle is pushed in the opposite direction and exited at a minimum of 5 cm from the entry point. Once each thread has been introduced in the same way, the skin is tightened between the two ends, and the thread is cut at the skin level under slight tension to allow for the thread to pull back under the skin. No dressing is usually required, but some strips can be used to release the skin tension (Figure 4C). Usually two to three threads are required for the Nasolabial folds, two for the marionette line, and two to three for the jaw line. Results do last for 12 to 18 months, depending on the quality and fat content of the skin.
Duration of results seems to be improved by combining the Silhouette Soft thread Lift with injection of a biostimulator like Ellansé (AQTIS Medical™, Utrecht, The Netherlands) 3 weeks after the procedure, in order to increase the collagen formation that will, at the end, be the only maintaining structure.
Drawbacks and complications
Whichever type of thread is used, there are usually common immediate temporary drawbacks — which cannot be considered as complications — but a normal sign of the procedure. Bleeding at the introduction or exit points is not uncommon. Oedema, asymmetry, disesthesia, skin irregularities or dimples have been described as frequent, but, with subdermal positioning allowing for spontaneous redraping of the skin32,33, they do not usually hold for more than a few hours to a few days (Figure 5).
Persistent asymmetries, hypo- or hypercorrection, persistent skin irregularities, visible or palpable threads, inflammation or inflammatory nodules, exposure of the threads, pain, paresthesia, and injury to the facial nerve, vessels or muscles are rare and likely to be related to errors in the technique, or insertion being too superficial (dermis) or too deep.
Rupture of the thread was thought by De Lorenzi32 to be due to excessive tension on the barb added to local pressure to correct this tension. Complete rupture of the threads is a consequence of the back-folding of the barbs, creating a weak point (Figure 6).
Few precise figures of infection or granulomatous reactions are reported in the literature. Sasaki and Cohen reported a total of 10% of complications on
392 patients. Most authors declare around 2%, but Helling states that ‘the published reports may underestimate the actual incidence of complications’23 (Figure 7).
From a better understanding of the ageing face processes, it is now clear that suspending threads are efficient on displaced fat. They should probably not be used to tighten the skin if too loose, even if some retightening may occur, either near the point of fixation for the unidirectional sutures, or close to the central point in the bidirectional ones.
In their study of 350 patients using the APTOS threads, the conclusion of Lycka et al34 was that ideal patients were young without many rhytids, or post facelift ones with mild to moderate residual facial laxity. As stated by Sapountis et al16 ‘although facial soft tissue lifting with minimal invasive procedures such as subdermal sutures is quite attractive in selected cases, the treatment of complications might be very challenging’.
In the patients with a greater skin laxity, indications will be for combined procedures, superficial ones to treat the dermis (peelings, lasers of different types, radiofrequency, injectable biostimulators, resorbable threads) or the underlying muscles (Botulinum Toxin, cryotherapy). But they also allow for less extensive face lifting surgical procedures, as they can achieve a proper treatment of the nasolabial folds and marionette lines by repositioning the displaced fat.