One of the major dangers associated with dry needling is pneumothmorax. Although documented cases are rare a needler should still exercise utmost precautions because of two reasons. First, it is a serious, even potentially fatal hazard. Second, the margins of safety are low. One article reports iatrogenic pneumothorax caused even by a dry needling instructor with 45 years of experience, so one should always take enough measures to ensure safety while needling around the thorax.
SPIDER is a combination of six very important steps which I believe would provide significant protection against the risk of pneumothorax (and also other needling related adverse effects like nerve damage or injury to the hollow organs). I would recommend going through these measures mentally every time one needles a patient.
S-surface anatomy
It is always a good idea to review the anatomy of any structure that you are going to needle. To prevent pneumothorax ALWAYS review the surface anatomy of pleura before needling around chest wall.
The Pleura extends into the neck superiorly, from the medial 1/3 of the clavicle to the sternoclavicular joint. The apex lies about an inch (sometimes higher) above the clavicle. One should be careful in while needling the structures here as the pleura can be just half a centimeter below the skin for lean individuals. The superior part is bound laterally by first rib. As it does not enjoy the protection of the ribs in the top where only covering is Sibson’s fascia, it is very easy to damage the pleura at this area. Remember the entry scene of Achilles in the movie ‘Troy’? He killed the giant with one clean strike by digging his sword precisely in that area.
Pleura also needs to be avoided diligently while needling the structures in the back. The medial margin of the pleura extends along the transverse processes of C7 till T12, sometimes L1. The book “Trigger point dry needling” by Jan Dommerholt mentions a ‘safe needling zone’ which is about a finger width lateral to the spinous process. Needle anywhere beyond that and you have a risk of reaching the lung.
P-position
Be mindful of both patient’s position and the position of the needle. One should be aware that with alterations in body position the arrangement of muscles gets changed in surface. For example in prone lying if the arms are kept forward the lower border of the trapezius muscle shifts superior and somewhat medially. Similarly, with posture change the ribs may open up more (e.g. in side lying if the arm is abducted, to needle serratus anterior).
The needle should be positioned over the skin with precision before tapping it in. If possible move the target tissue over a rib. Travel and Simon has also recommended fixing the target tissue by keeping one finger each in upper and lower intercostals spaces of the rib. The needle should always be positioned away from pleura and other vulnerable structures (e.g. femoral nerves, while needling the adductors.)
I-incidence Angle
Incidence angle is the angle at which the needle is inserted. While needling structures like rhomboids the angle should be very narrow, almost parallel to the skin to avoid pleura. For the muscles that attach to scapula it is usually recommended to aiming the needles towards the bone which stops the needle like a shield and protects the pleura.
It is important to recognize that at the same point of entry a wrong incidence angle can easily reach the pleura and create problem, for example, whie needling the thoracic multifidus in the ‘safe needling zone’ if the needle is angled laterally (instead of the recommended medial direction) it will definitely puncture the pleura. Similarly, while needling the piriformis directing the needle away from the sciatic nerve will be essential.
Correct incidence angle is also important for needling the correct structure.
D-depth
The depth of the target tissue should be judged and the size of the needle should be selected accordingly. The needler should have a fair bit of idea about the depth of the tissue and needle should be advanced no further than necessary.
If you are not comfortable inserting the needle at a depth stay superficial. You will still give the patient A delta mediated analgesia and there is a fair bit of possibility that the trigger point will get resolved by SDN mechanism.
E-educate
While taking the informed consent the patient should be educated about the potential adverse effects and how to identify them whether they are simple soreness or pneumothorax. Many a times pneumothorax can develop after a patient has left the clinic. This article reports a case of pneumothorax which was developed about six hours after dry needling. The article also mentions the symptoms of it as the patient (a medical doctor) experienced them. The patients should know what action they need to take if the adverse effects appear.
One should also educate the patient about the do’s and don’ts after needling. A small poke to the pleura may remain asymptomatic and heal itself if the patient avoids heavy upper limb activity for the remainder of the day of needling.
R-record
Like any manual therapy sessions needling interventions should be recorded. Every relevant detail need to be mentioned. I have created a simple dry needling recording technique which I will post soon.
While practicing SPIDER will definitely reduce the risk of pneumothorax and other adverse needling effects while needling, be weary of at risk population. Patients who are lean individuals, have a history of emphysema or other lung diseases or have chest wall deformities are not the best candidates to receive DDN on the chest wall. Above all, remember this maxim from Benjamin Franklin: When in doubt, don’t.