The trigeminal tract and nucleus procedures in treatment of atypical facial pain

Surgical Neurology 64 (2005) S2:96 – S2:101 www.surgicalneurology-online.com

The trigeminal tract and nucleus procedures in treatment of atypical facial pain Yqcel Kanpolat, MDT, Ali Savas, MD, PhD, Hasan Caglar Ugur, MD, PhD, Melih Bozkurt, MD Department of Neurosurgery, School of Medicine, Ankara University, Ankara 06100, Turkey

Abstract

Background: Atypical facial pain (AFP) is a throbbing pain situated deep in the eye and malar region, often radiating to the ear, neck, and shoulders. The pain generally is not within any dermatomal or anatomical boundaries. Atypical facial pain is distinct from trigeminal neuralgia and its variants. Therefore, the treatment of AFP should be specified. There is also no consensus in the treatment of AFP. Two different treatment procedures on the trigeminal tract and nucleus in a series of cases with AFP are presented. Methods: Between 1989 and 2005, 17 patients with AFP, in whom previous therapies had failed, underwent computed tomography CT-guided percutaneous trigeminal tractotomynucleotomy (TR-NC). One patient with unfavorable response to TR-NC underwent trigeminal dorsal root entry zone (DREZ) operation. Results: In the series with AFP, pain relief was achieved in all of the 17 cases. TR-NC provided maximum to inadequate degrees of pain relief in 16 of 17 patients. Dorsal root entry zone operation provided partial relief in 1 case. Neither mortality nor serious permanent complication was observed in the series. Conclusion: Neurosurgical procedures such as TR-NC or trigeminal DREZ operation may be effective in the treatment of intractable AFP. The primary choice of operation should be TR-NC because this procedure is minimally invasive. Trigeminal DREZ operation, which affects a larger spread area, may follow if TR-NC fails. The indications and procedure of choice should be individually tailored, depending on the type of pain, underlying pathology, and experience of the surgeon. D 2005 Elsevier Inc. All rights reserved.

Keywords:

Atypical facial pain; Tractotomy; Trigeminal nucleus-tractus; DREZ; Pain syndromes

1. Introduction Atypical facial pain is one of the most difficult syndromes to define and treat in neurosurgical practice. Thus, understanding of the mechanism of the pain (pathology) and patient selection are very important to achieve optimal outcome. Atypical facial pain can be described as poorly localized facial pain presenting with burning sensation and nonparoxysmal characterization. The pain does not respond to classic anticonvulsant drugs. It crosses the midline at a ratio of 35% [8,21,22]. Patients also usually Abbreviations: AFP, atypical facial pain; CT, computed tomography; DREZ, dorsal root entry zone; TR-NC, trigeminal tractotomy-nucleotomy. T Corresponding author. Tel.: +90 312 417 40 78; fax: +90 312 419 36 84. E-mail address: [email protected] (Y. Kanpolat). 0090-3019/$ – see front matter D 2005 Elsevier Inc. All rights reserved. doi:10.1016/j.surneu.2005.07.018

have hyperesthesia and/or dysesthesia, and when this is the case, AFP should be considered among the central pain syndromes. Atypical facial pain and psychological pathologies such as depression are strongly associated, and anxiety is known to exacerbate the condition [4,7,8,18]. The aim of the study was to describe the effectiveness of the central procedure of CT-guided percutaneous TR-NC and trigeminal nucleus caudalis DREZ operation. 1.1. Anatomical description of trigeminal pain pathways for surgical orientation Trigeminal afferents that carry the sensations of pain and temperature bifurcate when entering the pons and send a caudal ward branch (called the descending trigeminal tract) into the medulla. The descending trigeminal tract overlies the spinal trigeminal nucleus in the posterolateral

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part of the spinal cord at the cervicomedullary junction. Primary sensory fibers from the 7th, 9th, and 10th cranial nerves also enter the descending tract of the trigeminal nerve. The 3 divisions of the trigeminal nerve have a special topographical organization in the descending tract of the nerve. The fibers from the 7th, 9th, and 10th cranial nerves lie behind the tract, almost medially. Trigeminal afferents that carry the sensations of pain and temperature, unlike other sensory modalities, descend in the spinal trigeminal nucleus [15]. The spinal trigeminal nucleus has 3 distinct subdivisions along its pontospinal extent: (1) the nucleus oralis, located rostrally between the pons and medulla; (2) the nucleus interpolaris, located intermedially; and (3) the nucleus caudalis, located at the medullospinal junction and extending down to the level of the C2 segment. The nucleus caudalis represents the substantia gelatinosa, and there is an extensive overlap between facial and high cervical afferents, where the 7th, 9th, and 10th cranial nerve afferents also terminate. The secondary caudalis neurons begin to fire like those contained in an epileptogenic area after deafferentation, and these neurons may provide the neuropathologic basis of central pain. Destruction of the oral pole of the nucleus caudalis plays a special role in pain relief [12]. Because the descending trigeminal tractus and nucleus caudalis are the initial central station of the fibers of the 5th, 7th, 9th, and 10th cranial nerves in the face and skull, they are important and efficient surgical targets in craniofacial central pain syndromes. 1.2. Surgical procedure of trigeminal TR-NC and DREZ operations Atypical facial pain is a pain syndrome of central origin; thus, therapy should involve central intervention.

Fig. 1. Schematic representation of TR-NC procedure with main anatomical structures at occiput-C1 level. FG, Fasciculus Gracilis; FC, Fasciculus Cuneatus; DTT, Descending Trigeminal Tractus; NC, Nucleus Caudalis; PST, Posterior Spinocerebellar Tract; LST, Lateral Spinothalamic Tractus.

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Fig. 2. Needle placement at occiput-C1 level on the lateral scanogram.

Destruction of the descending trigeminal tract in the medulla is known as trigeminal tractotomy (Figs. 1-4), whereas lesioning of the nucleus caudalis is known as trigeminal nucleotomy and lesioning of the whole substantia gelatinosa of the nucleus caudalis as the nucleus caudalis DREZ lesion [9,12- 15,19- 21,23]. 2. Materials and methods Between 1989 and 2005, 17 patients with AFP (10 women and 7 men; mean age, 55.9 years) underwent CTguided TR-NC procedure. All previous medical or surgical therapies had failed. A second TR-NC intervention was applied to 3 patients in whom pain relief was achieved after the first intervention, but pain recurrence was

Fig. 3. Final position of the needle in the target.

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3. Results Pain relief was achieved in 16 of 17 patients with AFP in whom TR-NC was performed. One patient who did not respond favorably to CT-guided TR-NC underwent trigeminal DREZ operation, which provided pain relief. There were 7 good (no pain with or without medication), 9 moderate (partial pain relief with medication), and 1 inadequate (same pain as before intervention) pain control. The DREZ operation provided good pain relief. There was neither mortality nor serious complication in the series, but 2 transient ataxias were recorded, which returned to normal within 2 months. 4. Discussion The term atypical is used to distinguish facial pain from trigeminal neuralgia because this pain syndrome is neither responsive to anticonvulsant drugs nor present in the sensory area of the trigeminal nerve; the use of this term demonstrates a lack of understanding of the AFP phenomenon. In the diagnosis of AFP, all other etiologies such as migraine, cluster headache, trigeminal neuralgia, dental pathologies, multiple sclerosis, and other cranial neuralgias should be ruled out [7]. Onset of the symptoms is usually related with emotional status of the patients. The patients lack confidence because no therapy relieves their pain. In addition, the pain must persist for at least 6 months to establish a definite diagnosis. However, when atypical pain is accompanied by psychiatric problems, it may be controversial to determine which preceded the other [22]. Burchiel [2] has proposed a new classification for the evaluation of facial pain based

Fig. 4. Final position of the electrode system in the target.

observed in the follow-up. One patient underwent trigeminal DREZ operation because TR-NC result did not provide sufficient pain relief. The pain was on the right half of the face in 7 patients and on the left in the remaining 10 patients. The mean follow-up was 52.6 months (range, 2 months to 13 years). The psychiatric conditions of the patients were evaluated, and proper medications were administered if needed. The features of the patients are presented in Table 1. Table 1 Features of the patients Patients

Age (y)

Sex

Side

Localization

Duration of symptoms

Response to previous treatment

Procedure

Pain control

Follow-up

Complication

1 (SA) 2 (SC ¸) 3 (XA)

48 77 65

F F M

R R R

Face, uvula Mandible, tongue Neck, ear, uvula

1y 4.5 y 10 y

No No No

Good Good Moderate

2y 5y 13 y

No No Transient ataxia

4 (AG) 5 (MC ¸)

55 65

F M

L R

3 mo 15 y

No No

Good Moderate

11 y 4 mo

No No

6 (ST) 7 (AC) 8 (CY) 9 (KK) 10 (I˙E) ¨) 11 (FO 12 (KG) 13 (XS) 14 (MM) 15 (HE) 16 (HA) 17 (GA)

44 73 45 64 38 57 70 50 70 48 41 41

F M M F F F M F F M M F

L L R R L L L L L R L L

Face, neck Face, pharynx, tongue Face Lip, maxilla Face Face, neck Face Ear, face Face Face Tongue Face Face Ear, shoulder, tongue

TR-NC TR-NC TR-NC twice + DREZ TR-NC TR-NC

4 mo 7 mo 3y 10 y 1.5 y 1.5 y 1y 10 y 25 y 10 y 4y 4y

No No No No No No No No No No No No

TR-NC twice TR-NC twice TR-NC TR-NC TR-NC TR-NC TR-NC TR-NC TR-NC TR-NC TR-NC TR-NC

Moderate Moderate Good Moderate Moderate Good Inadequate Moderate Moderate Moderate Good Good

1y 2y 10 y 5y 5y 7y 1 mo 3y 2 mo 4y 4y 2y

No Transient ataxia No No No No No No No No No No

F indicates female; M, male; R, right; L, left.

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on information in the patient’s history. However, he has emphasized that the category of AFP cannot be determined only by history. It requires psychological evaluation of the patient, including standardized testing. Nevertheless, the suggestions presented by the authors do not aid in any practical diagnosis or treatment modality for the patients with AFP. Atypical facial pain is a serious problem caused by various etiologies. Pain is nonparoxysmal and is usually constant (at first episodic and later becoming chronic). Its distribution usually does not fit an accurate anatomical localization and can be seen bilaterally. No stimulation such as touching, chewing, or talking has been identified as a triggering factor. A prominent psychiatric component can be observed. Before diagnosis, all possible causes of facial pain must be ruled out, and the patient should be carefully examined. The initial treatment of AFP is usually medical; however, a multidisciplinary approach should be adopted [4]. Because AFP is described among the neuropathic pain syndromes, antidepressant agents can be administered to reduce the neuronal activity and achieve pain relief [1]. Feinmann [7] demonstrated an 80% pain-free state with the use of antidepressants. Nonetheless, another study presents AFP as having a poor response to medical treatment [1]. The patient series presented for this syndrome is very limited, and no consensus has been reached on medical treatment. Eriksson et al [6] pointed out the role of transcutaneous electrical nerve stimulation on 11 patients, 4 of whom had total pain relief. However, the only consensus by Giller [8] and many other authors is that surgery, especially ablative surgery, is not efficient in the treatment of AFP. The presence of anastomoses between the portio major and portio minor of the trigeminal nerve has been shown, in addition to strong evidence of prevalent sensory fiber anastomosis with the motor root, rather than the opposite [23]. Furthermore, purported sensory nociceptive fibers have been detected in the trigeminal motor root. Keller and Van Loveren [16] have emphasized the need for reexamination of the territory of the somatic and visceral sensory system of the seventh nerve, through which some of the neuralgias currently categorized as atypical may be reassigned to the domain of the facial nerve rather than to the more stereotypic classification, pain of psychogenic origin. The study of Elrasheed et al [5], which is based on questionnaires, pointed out that there is no mutual understanding of the terminology, diagnosis, or treatment of AFP. Hunt [11] has discussed herpetic inflammations of the geniculate ganglion and the regions affected: internal and middle ear, tympanum, and cutaneous zone of the external ear. He has claimed that the cutaneous zone of innervations is well known, whereas the visceral component is sometimes neglected. Davis [3] has presented strong evidence of preservation of deep facial sensation, including nociception, after rhizotomy or ganglionectomy. He has asserted that deep sensation and pain could only be alleviated after sectioning of the facial nerve. Sachs

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[22] reported 4 cases of intractable face and head pain relieved by sectioning of the nervus intermedius. He also presented a case whose pain persisted after sectioning of the nervus intermedius and in whom pain was relieved only after the eighth nerve was sectioned. He indicated that the vestibular portion of the eighth nerve might carry fibers originating from the nervus intermedius. Keller and Van Loveren [16] have declared that the deep sensory component of the facial nerve described by Hunt [11] may account for some of the neuralgias currently classified as atypical neuralgias. Destruction of the oral pole of the nucleus caudalis, which probably acts on the pathology site, removes the pool of neuronal hyperexcitability, eliminates convergence, and severs the ascending intranuclear polysynaptic pathways [14,23]. Hosobuchi and Rutkin [10] conducted trigeminal tractotomy on a 58-year-old woman with AFP for 15 years. Postoperatively, the patient’s pain had completely resolved. In a series of descending trigeminal tractotomy, Lopez et al [17] obtained associated analgesia of the ipsilateral pharynx, tympanic membrane, and external auditory meatus in 5 of the 6 patients, which indicates the close proximity of the pain and temperature fibers of cranial nerves VII, IX, and X to those of the descending trigeminal tract. Our experience in this 17 case series confirms the argument that AFP benefits from central interventions. In the evaluation of efficiency, chronicity is important. The patients that demonstrate minimal to no benefit are all severely chronic. Because the response to treatment is poor after 10 years, early surgical intervention is recommended for the patients. The need for a target for surgical treatment has been highlighted as a controversial issue. In our opinion, for successful treatment of AFP, which is a central pain, the target should be the trigeminal tractus and nucleus caudalis. In our experience, all interventions to this target have proven efficient. Although we do not have the data required for standardization of the area and size of the lesion, it may nevertheless be said that the interventions to this area will prove effective. 5. Conclusion Atypical facial pain is a difficult syndrome to diagnose and treat in neurosurgical practice. The origin of the pain may be, not only the trigeminal nerve, but also the 7th, 9th, and 10th nerves. Neurosurgical procedures reducing the neuronal hyperexcitability in the descending trigeminal tractus, such as TR-NC and trigeminal nucleus caudalis DREZ operation, may be effective in the treatment of intractable AFP. TR-NC should be performed first, and if it fails, trigeminal nucleus caudalis DREZ operation should follow. Although there is presently still no conclusion regarding surgical treatment of AFP, this study is important not only because it is the largest series in the literature regarding

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treatment with TR-NC and trigeminal nucleus caudalis DREZ operation, but also because there was a significantly longer period of follow-up of the patients.

Acknowledgments This work was partially supported by the Turkish Academy of Science (TUBA; Ankara, Turkey). We express our gratitude to Mrs Safak Ugur for proofreading, to Mukaddes Kurum Yucel for formatting this manuscript, and to Ahmet Sinav MD for his creative drawing. References [1] Bullard DE, Nashold DS. The caudalis DREZ for facial pain. Stereotact Funct Neurosurg 1997;68:168 - 74. [2] Burchiel KJ. A new classification for facial pain. Neurosurgery 2003;53:1164 - 7. [3] Davis LE. The deep sensibility of the face. AMA Arch Neurol Psych 1923;9:283 - 305. [4] Elias WJ, Burchiel KJ. Trigeminal neuralgia and other neuropathic pain syndromes of the head and face. Curr Pain Headache Rep 2002; 6(2):115 - 24. [5] Elrasheed AA, Wortington HV, Ariyaratnam S, Duxbury AJ. Options of UK specialists about terminology, diagnosis, and treatment of atypical facial pain: a survey. Br J Oral Maxillofac Surg 2004;42(6): 566 - 71. [6] Eriksson MBE, Sjolund BH, Sundbarg G. Pain relief from peripheral conditioning stimulation in patients with chronic facial pain. J Neurosurg 1994;61:149 - 55. [7] Feinmann C. Long-term outcome of facial pain treatment. J Psychosom Res 1993;37:1 - 7. [8] Giller C. Atypical facial pain and anesthesia dolorosa. In: Burchiel K, editor. Surgical management of pain. New York7 Thieme; 2002. p. 311 - 6. [9] Guenot M, Bullier J, Sindou M. Clinical and electrophysiological expression of deafferentation pain alleviated by dorsal root entry zone lesions in rats. J Neurosurg 2002;97(6):1402 - 9. [10] Hosobuchi Y, Rutkin B. Descending trigeminal tractotomy. Arch Neurol 1971;25:115 - 25. [11] Hunt RJ. On herpetic inflammations of the geniculate ganglion: a new syndrome and its complications. J Nerv Ment Dis 1907;34:73 - 96. [12] Husain AM, Elliott SL, Gorecki JP. Neurophysiological monitoring for the nucleus caudalis dorsal root entry zone operation. Neurosurgery 2002;50(4):822 - 7. [13] Kanpolat Y. Percutaneous stereotactic pain procedures. In: Burchiel K, editor. Surgical management of pain. New York7 Thieme; 2002. p. 745 - 62. [14] Kanpolat Y, Savas A, Batay F, Sinav A. Computed tomography– guided trigeminal tractotomy-nucleotomy in the management of vagoglossopharyngeal and geniculate neuralgias. Neurosurgery 1998;43(3):484 - 90. [15] Kanpolat Y, Savas A, Caglar S, et al. Computed tomography–guided percutaneous trigeminal tractotomy-nucleotomy. Techniques in neurosurgery. Philadelphia7 Lippincott, Williams & Wilkins; 1999. p. 244 - 51. [16] Keller JT, Van Loveren H. Pathophysiology of the pain of trigeminal neuralgia and atypical facial pain: a neuroanatomical perspective. Clin Neurosurg 1984;32:275 - 93. [17] Lopez PD, Salazar FG, Sierra OM, Yague RC, Llaurado G, Lopez E. Trigeminal nucleus caudalis dorsal root entry zone radiofrequency thermocoagulation for invalidating facial pain. Neurochirurgica 2003;14:25 - 32.

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Commentary This article summarizes tremendous experience—the work of senior author for the last 16 years—unique and extremely impressive in safety and effectiveness. The technique itself is very elegant; the entire procedure can be accomplished in less than an hour. The pain that the patient experiences during the procedure is decreased by slower rise in electrode temperature, and the effect of surgery is usually immediate. Because the patients are awake and the radiofrequency lesion is preceded by test stimulation, many side effects arising from the destructive nature of surgery may be avoided. From personal experience with open and percutaneous CT-guided procedures for pain, I can say that open procedures are definitely more traumatic [2] and that percutaneous procedures require as much (or maybe even more) precision and accuracy. The main issue, however, remains the classification of pain. The authors present a strong argument for using the term atypical facial pain; but many, particularly in the United States, leave this wording for pure psychiatric problems because the pain does not follow anatomic boundaries, frequently crosses midline, and is almost always associated with depression, somatization, and others [1,5,6]. This major psychiatric connotation forces many to describe constant burning facial pain as trigeminal neuropathy or atypical trigeminal pain, although the pain may involve areas outside trigeminal nerve distribution. It is important to remember, however, that this type of pain is probably the hardest to control because the peripheral procedures usually do not work, trigeminal ganglion stimulation is technically difficult and rather unreliable, and experience with motor cortex stimulation is still quite limited (particularly for this indication). Percutaneous trigeminal tractotomy/nucleotomy is used also for trigeminal pain due to cancer and in classic deafferentation pain syndromes [3,4], and the results are comparable to the current series. In my opinion, with a high degree of success in otherwise hard-to-treat conditions, this procedure is definitely worth adopting for