The Effect of Low-level Laser Therapy on Trigeminal Neuralgia: A Review of Literature.
The effect of low intensity laser radiation in the treatment of acute and chronic pain is now established in many studies. Tri-geminal neuralgia is a pain passes through nerve's branches and its trigger is located in skin or mucosa that could lead to pain with a trigger stimulus. The pain involved branches of trigeminal nerve that sometimes has patients to seek the treatment for several years. Nowadays different treatments are used for relief of pain that most of them cause tolerance and various side effects. This paper reviews and summarizes scientific papers available in English literature publishedin PubMed, Scopus, Science Direct, Inter science, and Iran Medex from 1986 until July 2011 about the effect of these types of lasers on trigeminal neuralgia which is one of the most painful afflictions known. In different studies, the effect of laser therapy has been compared with placebo irradiation or medicinal and surgical treatment modalities. Low-level laser therapy (LLLT) is a treatment strategy which uses a single wavelength light source. Laser radiation and monochromatic light may alter cell and tissue function. However, in most studies laser therapy was associated with significant reduction in the intensity and frequency of pain compared with other treatment strategies, a few studies revealed that between laser and placebo group there was not any significant difference according to the analgesic effect. Low-level laser therapy could be considered in treatment of trigeminal neuralgia without any side effects.
Comparison between Trans-Cranial Electromagnetic Stimulation and Low-Level Laser on Modulation of Trigeminal Neuralgia
[Purpose] To determine which of the transcranial electromagnetic stimulation or low level laser therapy is more effective in the treatment of trigeminal neuralgia of multiple sclerosis patients. [Methods] Thirty multiple sclerosis patients of both sexes participated in this study. The age of the subjects ranged from 40 to 60?years and their mean age was (56.4–6.6). Participants were randomly selected from Dental and Neurology Outpatient Clinics at King Khalid Hospital, Najran University, Saudi Arabia. Patients were randomly divided into two equal groups of 15. The Laser group received a low level laser therapy, 830?nm wavelength, 10?Hz and 15?min duration, while the Electromagnetic group received repetitive transcranial electromagnetic stimulation at a frequency of 10?Hz, intensity of 50 mA and duration of 20 minutes. Patients were assessed pre and post treatment for degree of pain using a numerical rating scale, maximal oral mouth opening using a digital calibrated caliper, masseter muscle tension using a tensiometer and a compound action potentials of masseter and temporalis muscles. [Results] There were significant improvements after treatment in both groups, with a significant difference between the Electromagnetic and Laser groups, in favor of the Electromagnetic group. [Conclusion] Repetitive transcranial electromagnetic stimulation at 10?Hz, 50 mA, and 20 minutes duration is more effective than low level laser therapy at reducing trigeminal pain, increasing maximum oral mouth opening, masseter and temporalis muscle tension in multiple sclerosis patients.
Trigeminal neuralgia (TN) is an uncommon disorder characterized by recurrent attacks of facial pain in the trigeminal nerve distribution. Typically, brief attacks are triggered by talking, chewing, teeth brushing, shaving, a light touch, or even a cool breeze1). The pain is nearly unilateral, and it may occur repeatedly throughout the day. Trigeminal neuralgia is characterized by sudden, severe, brief, stabbing, and recurrent episodes of facial pain2). The prevalence ratio is 4 per 100,000 in the population, and commonly affects patients over 50?years, occurring more frequently in women than men with a ratio of 1.5–2:1, respectively1). It is also more common in patients with multiple sclerosis3). TN is associated with decreased quality of life and impairment of daily function. It impacts upon employment in 34% of patients and depressive symptoms are not uncommon4). The condition may be severely disabling with high morbidity particularly among the elderly5). It is evident that trigeminal pain occurs in multiple sclerosis because of pressure on the trigeminal nerve root at the entry zone into the pontine region of the brain stem6).Compression or insufficiency of blood supply may cause local pressure, leading to demyelination of the trigeminal nerve axon which causes ectopic action potential generation7). TN is almost always unilateral with the maxillary branch being most commonly affected and the ophthalmic branch the least8). Pain attacks usually last from a few seconds to 2?min and may recur spontaneously between pain-free intervals9).
Trans-cranial magnetic simulation (TMS) is a technique for stimulating of the human brain. A noninvasive stimulation technique, Repetitive Trans-cranial Magnetic Stimulation (rTMS), may be suitable for the treatment of chronic neuropathic pain as it modulates neural activities not only in the stimulated area, but also in remote regions that are interconnected to the site of stimulation9, 10). Prolonged pain relief can be obtained by repeating rTMS sessions every day for several weeks at 10 HZ frequency11).
A low-level laser (LLLR) produces photo-biochemical reactions that result in pain relief. Considering the effect of neurotransmitters on nerves, LLLR are expected to be effective in eliminating all kinds of pain that result from nerve irritation and nociceptor excitation (neuropathic pain)12). LLLR can reduce pain of inflammatory origin through their anti-inflammatory properties. Also, low-level lasers have been shown to be effective in alleviating oral and maxillofacial pain13). The hypothesis of the current study was that there are no differences between rTMS and LLLR treatments. The purpose of the current study was to determine which of rTMS or LLLR better reduces trigeminal pain, increases low oral mouth opening and improves the power of the masseter and temporalis muscles in TN of multiple sclerosis patients.
SUBJECTS AND METHODS
This study was conducted at Dental and Neurology Outpatients Clinics at King Khalid Hospital, Najran University, Saudi Arabia. Thirty multiple sclerosis patients with TN (of all branches) of both sexes were randomly selected and participated in this study. Diagnosis was carried out by a neurologist through the use of physical examination and magnetic resonance imaging (MRI). Patients' ages ranged from 40 to 60?years and their mean age was 56.4 ± 6.6?years. The weights of the subjects ranged from 60 to 80?kg, and their mean weight was 75.00–7.7?kg. Classical TN was diagnosed according to the International Classification of Headache Disorders2 Criteria14), and the duration of illness ranged from 6 to 12 months (Table 1). Pain during attacks should not be less than six according to a numerical rating scale (NRS), with no satisfactory medical pain relief in the last three months. Patients were conscious, co-operative and free from psychological disorders (as documented by a psychologist), and disabilities secondary to orthopedic problems or special senses impairments. Patients were excluded if they had TN secondary to tumor, herpes zoster or any another causes, i.e. serious cardiopulmonary dysfunction, past invasive treatment (radiofrequency, ethanol, glycerinum injection, Gama-knife microvascular decompression) or coagulation dysfunction. Patients were randomly divided into two equal groups of 15 by a random allocation method (thirty folded papers were allocated in a bag, with two series of 15 papers on which were written either LG or MG and every patient had the chance to choose one folded paper).
The Laser group (LG) consisted of 15 patients whose ages ranged from 40 to 58?years with a mean age of 48.80–6.3?years, and a weight range of 65 to 88?kg, with mean weight of 75.26–6.80?kg. They were treated with an 830?nm wavelength LLLR15).
The Electromagnetic group (MG) consisted of another 15 patients, whose ages ranged from 45 to 60?years, with a mean age of 46.66–9.608?years, and a weight range of 60 to 87?kg, with a mean weight of 74.80–727?kg. They received rTMS at 10?Hz frequency10). There were no significant pretreatment differences between the groups in demographic characteristics (p>0.05) (Table 1).
An electromyography device (Neuropac Apparatus, Tensiometer: Lafayette, USA 3) was used to measure the motor action potentials of the temporalis and masseter muscles. A calibrated caliper (Chattanooga, USA) was used for mouth opening measurements. An ASA Electromagnetic device with the following characteristics; PMT Quattro model, PRO voltage 230 v., frequency 50/60?Hz, absorbed power 850 VA-Class I. Type B, EN 60 601-1 1990. Made in Italy 2002. A Laser device (SN: 5EZ303, Made in Italy).
After informed consent had been obtained, all patients participated in several trials with the equipment to be psychologically assured and to familiarize themselves with the treatment steps. The treatment was performed three times per week on consecutive days for eight weeks of total twenty four sessions.
The pain intensity of all patients was assessed using NRS16) (0=no pain, 5=moderate pain, 10=worst pain), when patients were not under medication. The masseter and temporalis muscle compound motor action potentials of all patients were measured before and after treatment.
The subjects were seated comfortably upright and were asked not to move their heads during recordings. A stimulating needle electrode was placed intra-orally on the nerve branch at the medial angle of the mandible. The recording electrodes were positioned on the masseter muscle belly parallel to muscular ?bres about 3?cm above and anterior to the mandibular angle, two centimeters distance from the two recording electrodes. This electrode placement was demonstrated to be optimal for avoiding cross-talk responses from facial muscles17). The electrode over the anterior temporalis was placed just in front of the hairline; the reference electrode was placed just above the eyebrow. The signals were amplified, filtered, and digitized at 1,000?Hz by the Spike 2 system (Cambridge Electronic Design, Cambridge, UK)18). For the assessment of maximal Active mouth opening range, patients were asked to open their mouths as much as possible with their heads fixed, and the vertical distance between upper and lower teeth was measured using a calibrated caliper with 1?mm accuracy19, 20). For the assessment of muscle power, patients were instructed to tightly clench their mouth as much as possible for assessment of masseter muscle power, and the amount of tension was recorded by a tensiometer.
Subjects in the Laser group were treated with a low power 15mW helium-neon laser of wave length 830A units and a laser beam density of 150–170 mw/cm2 for irradiation. The treatment was first given intra-orally following the path of the nerve branch for 1–2?min, then extra-orally on the most tender points for 10?min. In the sitting position, the contact laser technique was used on the skin overlying the four tender points of the face21, 22). Subjects in the electromagnetic group received repetitive TMS at a frequency of 10?Hz, 50 mA intensity, and 20 minutes duration. In the sitting position with all metal objects removed the splenoid was applied tangentially over the patient's head, and held on one side (contra-lateral to trigeminal pain). A rest period of 10 minutes after application was allowed for all patients23, 24). The results of both groups were statistically analyzed to compare the differences within each group and the differences between the two groups. The statistical package of social sciences (SPSS, version 10) was used for data processing and a p=0.05, as the level of significance.
The results showed no significant pretreatment differences between the two groups in pain intensity, masseter muscle tension, or maximal mouth opening, masseter and temporalis compound action potentials p>0.05 (Table 2).
There was significant post-treatment reduction in pain intensity in LG compared to the pretreatment mean value, (p=0.01), and a highly significant post-treatment reduction in pain intensity in MG when compared to pretreatment mean value (p=0.001) (Table 3). Significant differences was found between the post-treatment values of the two groups, with the best result in MG (p=0.01) (Table 4).
There was significant post-treatment improvement in masseter tension in LG compared to the pretreatment mean value, (p=0.01), and highly significant post-treatment improvement in MG compared to the pretreatment mean value (p=0.001) (Table 3). Significant differences was found between the post-treatment values of the two groups, with the best result in MG (p=0.01) (Table 4).
There was significant post-treatment improvement in mouth opening in LG compared to the pretreatment mean value, (p=0.014), and highly significant post-treatment improvement in mouth opening in MG compared to pretreatment mean value, (p=0.001) (Table 3). Significant differences was found between the post-treatment values of the two groups, with the best result in MG (p=0.001) (Table 4).
There were significant post-treatment improvements in masseter and temporalis CAP in LG compared to the pretreatment mean values, (both, p=0.01), and highly significant post-treatment improvements in masseter and temporalis CAP in MG compared to the pretreatment mean values (respectively p=0.001 and p=0.003) (Table 3). Significant differences was found between the post-treatment values of the two groups, with the best results in MG (masseter, p=0.001 and temporalis CAP, p=0.003) (Table 4).
The purpose of the study was to determine which of transcranial electromagnetic stimulation or low level laser therapy is more effective for trigeminal neuralgia of multiple sclerosis patients. Low level laser therapy (LLLT) has been used clinically and some researchers have reported the efficacy of LLLT in the treatment of various pain conditions21). In the present study, there were significant improvements in TN compared to pretreatment measurements and the results of NRS indicated a slight but significant reduction in facial pain. Patients also noted a reduction in their anxiety symptoms. Moreover, the present results showed a significant improvement in maximal mouth opening after application of LLLT. These findings are in agreements with reports of significant reduction in pain and improvements of range of motion after 3 months of LLLT22, 23).
The present study showed a strong relationship between the application of repetitive transcranial electromagnetic stimulation and the improvement of TN symptoms. There was reduction of pain according to NRS. These results are in agreement with those of another study that applied the TMS at 5?Hz to treat orofacial pain patients24). In the present study, 10?Hz rTMS was applied to treat TN patients and there was a highly significant improvement in maximal mouth opening. This result was confirmed by other result who demonstrated that application of rTMS at 5?Hz or more was able to relieve neuropathic pain25), this was also in agreement with the study that applied four different frequencies (0.5?Hz, 1?Hz, 5?Hz and 10?Hz) of rTMS to treat patients with orofacial pain ; the best results was at 10?Hz26). The efficacy of rTMS in producing significant analgesia seems to depend on a precise targeting the frequency. It has been reported that application of rTMS sessions over the motor cortex can produce excitatory changes in the brain and induce excitation of the muscles action potentials27). The application of low frequency TMS may alter cerebral excitability, brain rhythms, and a variety of human behaviors28,29,30).
The present study found that there were improvements in the masseter muscle tension in bothtreatment groups with the best results in rTMS group. These findings are supported by other studies that reported significant improvement in the cervical muscle together with significant improvements in the range of motion and relief of pain due to an inhibitory effect on neural discharges around the stimulated cortical areas31).
The study concluded that repetitive transcranial electromagnetic stimulation at 10?Hz and 50 mA, for 20?min is considered more effective than low level laser therapy at reducing trigeminal pain, and improving the maximum mouth opening, and masseter and temporalis muscle tensions of multiple sclerosis Patients. It is also considered more useful and safe modality than drugs for other orofacial dysfunctions.
We recommend the investigation of the long-term effects of both rTMS and LLLT in various orofacial dysfunctions at different frequencies, durations and intensities, as well as rTMS for other painful neurological disorders.
Vopr Kurortol Fizioter Lech Fiz Kult. 2000 Nov-Dec;(6):29-32.
Physiopuncture therapy of trigeminal neuralgia
[Article in Russian]
Samosiuk IZ, Kozhanova AK, Samosiuk NI.
137 patients with typical trifacial neuralgia (TN) were divided into four groups. 30 patients of group 1 received EHF therapy, 30 patients of group 2 were exposed to laser, 67 patients of group 3 were treated with combination of laser with EHF-puncture, 10 patients of group 4 were controls on conventional physiotherapy. Patients of all the groups were given drug of choice–carbamazepin. The highest response was registered in group 3, 21(31.3%) patients of which could stop carbamazepin, while 40(59.7%) patients reduced carbamazepin dose by 50-70%. Positive results were due to restoration of self-regulation in pain and antipain systems which are disturbed in TN patients
J Clin Laser Med Surg. 1998 Aug;16(4):223-6.
Low-level laser therapy is an important tool to treat disorders of the maxillofacial region.
Pinheiro AL, Cavalcanti ET, Pinheiro TI, Alves MJ, Miranda ER, De Quevedo AS, Manzi CT, Vieira AL, Rolim AB.
Laser Center, School of Dentistry, Universidade Federal de Pernambuco, Brazil.
OBJECTIVES: The authors report on the effects of low-level laser therapy (LLLT) in the treatment of maxillofacial disorders. SUMMARY AND BACKGROUND DATA: Further to our previous studies, this paper reports the results of the use of LLLT on the treatment of several disorders of the oral and maxillofacial region. This paper presents LLLT as an effective method of treating such disorders. METHODS: Two hundred and five female and 36 male patients ages between 7 and 81 years old (average 38.9 years old), suffering from disorders of the maxillofacial region, were treated with 632.8, 670, and 830 nm diode lasers at the Laser Center of the Universidade Federal de Pernambuco, Recife, Brazil (UFPE). The disorders included temporomandibular joint (TMJ) pain, trigeminal neuralgia, muscular pain, aphatae, inflammation, and tooth hypersensitivity postoperatively and in small hemangiomas. Most treatment consisted of a series of 12 applications (twice a week) and in 15 cases a second series was applied. Patients were treated with an average dose of 1.8 J/cm2. RESULTS: One hundred fifty four out of 241 patients were asymptomatic at the end of the treatment, 50 improved considerably, and 37 were symptomatic. CONCLUSIONS: These results confirm that LLLT is an effective tool and is beneficial for the treatment of many disorders of the maxillofacial region.
J Clin Laser Med Surg. 1997;15(4):181-3.
Low-level laser therapy in the management of disorders of the maxillofacial region.
Pinheiro AL, Cavalcanti ET, Pinheiro TI, Alves MJ, Manzi CT.
School of Dentistry, Universidade Federal de Pernambuco, Recife, Brazil.
OBJECTIVE: The authors analysed the effects of low-level laser therapy (LLLT) on the treatment of maxillofacial disorders. SUMMARY BACKGROUND DATA: Pioneer work published by Mester et al. opened a new frontier in the clinical treatment of many disorders with the use of LLLT. Although LLLT is not well accepted in many places, its use is growing steadily in others, including Europe and more recently in Brazil. METHODS: One hundred forty-one female and 24 male patients, between 7 and 81 years of age (average = 39.2 years old), suffering from disorders of the maxillofacial region were treated with 632.8-nm, 670-nm, and 830-nm diode lasers at the Laser Center of the Universidade Federal de Pernambuco. The disorders included temperomandibular joint pain, trigeminal neuralgia, muscular pain, aphatae, inflammation, and tooth hypersensitivity both postoperatively and in small hemangiomas. Most treatment consisted of a series of 12 applications (twice a week), and in eight cases a second series was applied. Patients were treated with an average dose of 2.5 J/cm2. RESULTS: One hundred twenty out of 165 patients were asymptomatic at the end of the treatment, 25 improved considerably, and 20 were symptomatic. CONCLUSIONS: These preliminary results indicate that LLLT is an important tool and brings many benefits for the treatment of many disorders of the maxillofacial region.
CAN LOW REACTIVE-LEVEL LASER THERAPY BE USED IN THE TREATMENT OF NEUROGENIC FACIAL PAIN? A DOUBLE-BLIND, PLACEBO CONTROLLED INVESTIGATION OF PATIENTS WITH TRIGEMINAL NEURALGIA
Arne Eckerdal and and Lehmann Bastian
Department of Oral and Maxillofacial Surgery and Oral Medicine, Odense
University Hospital, Denmark
Neurogenic facial pain has been one of the more difficult conditions to
treat, but the introduction of laser therapy now permits a residual group of
patients hitherto untreatable to achieve a life free from or with less pain.
The present investigation was designed as a double-blind, placebo controlled
study to determine whether low reactive-level laser therapy (LLLT) is
effective for the treatment of trigeminal neuralgia. Two groups of patients
(14 and 16) were treated with two probes. Neither the patients nor the
dental surgeon wereaware of which was the laser probe until the
investigation had been completed. Each patient was treated weekly for five
weeks. The results demonstrate that of 16 patients treated with the laser
probe, 10 were free from pain after completing treatment and 2 had
noticeably less pain, while in 4 there was little or no change. After a one
year follow-up, 6 patients were still entirely free from pain. In the group
treated with the placebo system, i.e. the non-laser probe, one was free from
pain, 4 had less pain, and the remaining 9 patients had little or no
recovery. After one year only one patient was still completely free from
pain. The use of analgesics was recorded and the figures confirmed the fact
that LLLT is effective in the treatment of trigeminal neuralgia. It is
concluded that the present study clearly shows that LLLT treatment, given as
described, is an effective method and an excellent supplement to
conventional therapies used in the treatment of trigeminal neuralgia.
Addressee for Correspondence: Arne Eckerdal DDS DOS Consultant, Departmentof Oral and Maxillofacial Surgery & Oral Medicine, Odense University
Hospital, DK-5000 Odense' Denmark.
12/96 Rep. US X 8-10-12
LASER THERAPY, 1996:: 8: 247-252
Tandlægebladet. 1994; 98 (2): 526-529.
GaAlAs laser treatment evaluated for trigeminal neuralgia, paresthesia, atypical facial pain and temporo-mandibular joint pain in a 5 year study.
Eckerdal A, Lehmann Bastian H.
Can low reactive-level laser therapy be used in the treatment of neurogenic facial pain? A double-blind, placebo controlled investigation of patients with trigeminal neuralgia. Laser Therapy. 1996; 8: 247-252. At the Odense University Hospital, Denmark, Arne Eckerdal has evaluated the effect of 830 nm, 30 mW, laser treatment for a number of indications. Patients suffering from trigeminal neuralgia (n = 36) had a positive result in 81% at the end of treatment, 42% at 1-year control. Patients having received previous alcohol blocks (n = 14) responded less favourably to the treatment. 50% were pain free at the end of the treatment period, 20% at 1 year control. Patients with non-specific facial pain (n = 63) were pain free at the end of treatment, 44% at follow up one year later. In a group of 22 patients with paresthesias (n = 22), only 5 were successful at end of treatment , 4 were improved and 13 were not improved. The result at 6 and 12 months were the same. Patients with temporo-mandibular pain (n = 40) were improved in 73% and at 1 year control still 70% were pain free.
LOW INTENSITY LASER THERAPY (LILT) IN THE MAXILLOFACIAL REGION
Paul Bradley The Royal London School of Medicine and Dentistry, London, England
The region of the face and mouth is well suited to Low Intensity Laser Therapy (LILT) in view of ease of access. It is also an area associated with a variety of painful conditions and intractable ulcers which have proved amenable to LILT in a total of around 500 cases. Our practice is based on several postgraduate research projects:
1. Studies of depth penetration of 820nm. These have been undertaken using a CCD camera to demonstrate penetration depths in non vital tissue specimens augmented by observations in the living subject with isotropic detectors.
2. Investigation of vascular response. A thermographic camera has been used for local heating effects while laser doppler has been employed to measure microcirculatory flux. Ultrasound doppler allowed monitoring of arterial status. A variety of wavelengths and fluxes have been investigated.
3. Double blind clinical trial in temporomandibular joint disorder pain. Methods have included algometry for pressure point thresholds, electromyography for muscular activity and sensor tracking for mandibular movement.
4. Study of effect on osseointegration of implants in jaw and femur. Research methods have involved mechanical push out testing, radiovisiography, x-ray microtomography and histomorphometry in the rabbit experimental model. On the basis of the data acquired clinical practice has been undertaken particularly in the following conditions:
1. Post Herpetic Neuralgia,
2. Temporomandibular Joint Disorder Pain
3. Trigeminal Neuralgia
4. Atypical Facial Pain,
5. Pain from Acute Maxillofacial Trauma
6. Palliation of Pain from Unresectable Orofacial Cancer,
7. Intractable Oral Ulcerations, 8. Nerve Lesions,
9. Cavernous Haemangiomas Of the Facial Region in Infants
The results of this clinical practice are described and analyzed.