Ethics Statement
The study was conducted in accordance with the Declaration of Helsinki approved by the Ethics Committee of Poznan University of Medical Sciences (no. 630/13). All subjects gave written informed consent to participate in the study before data collection. A detailed description of all examination and treatment procedures, including dry needling (DN), and risks involved in this study has been provided to the participants. Participants had the right to refuse DN treatment and withdraw from the study at any time without penalty.
Case 1
A 57-year-old female presented to the University outpatient clinic with a twelve weeks history of progressive pain in the left lower extremity and low back pain (LBP). Her past medical history was remarkable for several prior episodes of lower back pain. She described her state as aggravating with time, her pain ranged between 3 and 8 points on the visual-analogue scale (VAS). The patient reported pain in the lower back, groin and posterolateral thigh. She complained of some temporary but severe pain in the calf and foot, especially during the night. Standard treatment for radicular pain failed (she received miorelaxants, anti-inflammatory drugs and pain-killers (paracetamol, opioids). She was re-diagnosed with sciatica of radicular origin by an independent university neurologist. The diagnosis was based on detailed bedside neurological examinations and extensive neurological screening examination (NSE). Lasegue test, femoral nerve tension test, passive dorsiflexion test (Bragard test) and Lasegue test plus neck flexion were all positive, cross Lasegue sign was the only negative.
The locomotor system examination confirmed tension of the paraspinal muscles on the left side at L2/L3 and pain of the spinous processes. Although a slight muscle weakness for flexion and extension (4/5) of the thigh and knee on the right side was discovered, other parameters were normal (5/5). Results of other neurological assessments were normal. Magnetic resonance imaging (MRI) scan of the lumbar and sacral spine revealed right disc protrusion at L3-L4 indenting thecal sac and the same side disc-root conflict. No abnormalities in sacroiliac joint were found. In the electromyographical examination, (erector spinae, quadratus lumborum, gluteus maximus, rectus femoris and gastrocnemius), a normal result was found during rest. In maximum contraction, features of bilateral motor unit dysfunction in innervation of L4-L5, L5-S1 were discovered. Conduction of motor fibers in examined nerves in lower limbs was normal, as was conduction of motor fibers in ventral root L5-S1. Laboratory tests revealed leukopenia, neutropenia, lymphopenia and monocytosis (WBC 3,3×10µ3/ µL, 1,6×10µ3/ µL, 1,3 ×10µ3/ µL and 10,9% respectively, ESR and C-reactive protein (CRP) were within limits ESR -12/lh, CRP -0.1 mg/l.
Case 2
A 49-year-old female presented to the University outpatient clinic with a four weeks history of intensive pain in left lower extremity and low back pain. Medical history revealed several prior episodes of LBP which started in 2003. The patient confirmed the level of pain as 8 according to VAS. The pain covered her lower back, lateral thigh, calf and lateral edge of the foot. Apart from the pain, she also complained of numbness. Previous sciatica treatment failed (she received thiamin pyrophosphate, cobalamin, anti-inflammatory drugs and paracetamol). Based on detailed bedside neurological examinations and NSE, she was re-diagnosed with sciatica of radicular origin by an independent university neurologist. These examinations revealed abnormal gait on the heel of the left foot, slight weakness of the left foot inversion (4/5), left foot dorsiflexion (4/5), great toe dorsiflexion (4/5) and temperature dysesthesia of the lateral edge of the foot. While the examination revealed a positive Lasegue test, Bragard test and Lasegue test plus neck flexion, the rest of the tests were negative. Other results of neurological examination were normal. The following results were confirmed through MRI examination: posterior disc bulging without thecal sac compression at L2-L3, minor disc protrusion with thecal sac modelling and a disc-root conflict at L3-L4, bilateral disc-root conflict at L5, severe compression of the left nerve root and thecal sac at L5-S1, and L5-S1 disc space narrowing due to disc protrusion. No abnormalities in sacroiliac joints were found. Similarly to case one patient, electromyographic and electroneurographic examinations were carried out. Although their results turned out to be normal, during maximuml contraction, motor unit dysfunction features were discovered in the left side of L4-L5 innervation. Laboratory tests revealed a slight monocytosis (11%), elevated MCV (116.3 fL) and MCH (39.5 pg). Other parameters were normal - the erythrocyte sedimentation rate (ESR) reached 4/lh, C-reactive protein levels (CRP) reached 0.1 mg/l.
Case three
A 46-year-old female presented to the University outpatient clinic with a three weeks history of intensive pain in the left lower extremity and low back pain. She confirmed the level of pain on five according to VAS. Patient localised the pain in the lower back, posterior-lateral thigh and calf. She received pain killers and anti-inflammation drugs from her GP. She was diagnosed by university neurologist with sciatica-like symptoms on the basis of bedside examinations and NSE (a norm for every component of the test was confirmed). Leftward disc herniation at the L5-S1 with left nerve root intracanal compression were the only abnormalities registered in MRI. In electroneurography, no dysfunction of peripheral conduction of lower limb nerves was discovered. However, by means of electromyography, features of motor unit dysfunction in L4-L5 innervation were recorded on the left side during maximal contraction. Laboratory tests confirmed neutropenia (NEUT#1.93×10µ3/ µL; NEUT% 33.6%), slight monocytosis (MO# 0.83×10µ3/ µL; MO% 14.3%); elevated levels of lymphocytes 49.8%; and trombocytosis 863×10µ3/ µL. Other results were normal - ECR 8/lh, CRP 5.3 mg/l.
Myofascial pain examinations
In the patients, the presence of an active trigger point in the anterior fibres of the gluteus minimus muscle (GM) was confirmed according to Travell and Simons’ criteria [3]. Within the GM, two most painful points with referred pain were marked. Then, the participants were subject to dry needling technique performed in the previously marked points under control of an infrared thermovision camera. Needling was performed with 0.30 mm diameter, 60 mm long sterile acupuncture needles SE L (Serin Corp, Shizuoka, Japan). Each needle was packed separately. The needle pierced the skin and reached the painful point with referred pain. The recognizable pain started to withdraw partially and repeatedly and eventually both the pain and muscle fiber contraction subsided. The time of needling was maximum 6 minutes for any given point. After needling of both points was conducted, further thermovisual imaging was performed. At the end, a set of thermovisual images of the final state was recorded. For the diagnostic test, a thermovision touchless camera using the 8-14 µm waveband and working in real time was applied. The camera was equipped with uncooled VOx (vanadium oxide) microbolometer. To obtain the stability of patient’s body temperature and to ensure the adjustment of the recording camera’s temperature to the interior conditions, the evaluation began 30 minutes after the patient had entered the examination room. Thermal isolation of the evaluated area from other thermal factors that might have influenced the evaluation, including other parts of the patient’s and doctor’s bodies was ensured. Moreover, when performing thermovisual imaging, the general rules of camera usage were followed.
During the evaluation, all thermovisual images were measured and recorded within the measurement range displayed by the camera and set between 25 and 45 degrees Celsius (in individual cases lower levels of temperature can be set).
Results of the infrared thermovisual observation
After dry needling of active TrPs in the gluteus minimus muscle in the pain area (sciatica), the short-term vasodilation effect was recorded (under infrared thermovision camera) (Figure 1). The increase of maximum and average temperature (Tmax, Tavr) limited to the subarea with vasodilation effect was confirmed (case 1 ΔT max +1.3°C; ΔT avr 0.9°C; case 2 ΔT max +2.1°C; ΔT avr 1.1°C; case 3 ΔT max +2.1°C; ΔT avr +1.8°C). Subareas with the vasodilation of the highest temperature increase are shown on Figure 2. Dry needling provoked spreading of subareas (iso-areas) with the highest temperature. For case one patient, the iso-area 6.9 cm2 (35.6°C) spread to 59.9 cm2 (35.6°C -36.2°C) post-needling, and in rest position six minutes later, further spreading was observed – finally the area reached 361.4 cm2 and the temperature rose to 36.9°C, then a slow decrease of the vasodilation subarea and temperature were observed. For case two respectively: 9.1 cm2 (35.7°C) to 119.3 cm2 (36.2°C) to 232.3 cm2 (36.2°C). For case three: 0.1 cm2 (34.2°C) to 508.6 cm2 (34.9°C) to 635.7 cm2 (36.5°C).
In each of these cases, the first manifestations of vasodilation were recorded immediately after needle insertion to a trigger point. The vasodilation effect increased during DN, reached its highest at approximately 6 minutes post DN and decreased afterwards. These reactions depended on pain severity during procedure and the time post-DN (Additional file 1).