Cryotherapy in the management of paroxysmal trigeminal neuralgia

J.max-fac. Surg. 14 (1986) J. max.-fac. Surg. 14 (1986) 5-7 © Georg Thieme Verlag Stuttgart • New York

Cryotherapy in the Management of Paroxysmal Trigeminal Neuralgia. Four Year Follow Up of 39 Patients Joanna M. Zakrzewska, Fergal F. Nally, Stephen R. Flint Department of Oral Medicine (Head: Dr. F. F. Nally, MD, FDSRCS (Eng) FFDRCSI), University of London, Institute of Dental Surgery, London, GreatBritain

Submitted 8.3. 1985; accepted 16.4. 1985

Introduction The use of cryoanalgesia was first reported by Lloyd et al. (1976) with encouraging results. They treated 64 patients suffering from intractable pain, 6 of whom had facial neuralgia. Barnard et al. (1978) using cryotherapy for many types of chronic facial pain obtained a median duration of relief of 116 days. In 24 patients with paroxysmal trigeminal neuralgia (PTN) Barnard et al. (1981) reported a mean relief period of 160 days. At the end of the year only 16 % had full pain relief. Our experience suggests that some of these patients may have developed pain migration which accounts for their short period of relief. Other peripheral techniques have been used to avoid major surgery. None purports to be curative and some are complicated by neuroma formation, anaesthesia dolorosa and neurological deficits. Repeating these procedures can also be difficult and is often unsuccessful. Peripheral neurectomy, alcohol or phenol injections and peripheral radiofrequency thermolysis (Gregg et al., 1978) have been advocated but are now rarely used. Cryotherapy for the relief of PTN has been used successfully since 1978 at this Institute (Nally 1984, Nally et al. 1984).

Material Thirty nine patients were treated by an identical cryotherapy technique and followed up for at least 4 years with a maximum of 5½ years. There was no loss of patients to follow up. Diagnostic criteria were: 1. Pain in the distribution of the trigeminal nerve. 2. Pain of electric shock, shooting or stabbing character, of short duration and showing refractory periods. 3. Presence of trigger zones. 4. Paroxysmal pain with episodes of complete remission. 5. Pain provoked by innocuous stimuli. 6. No sensory deficit on standard neurological examination. 7. Absence of positive findings on special tests, for example radiography and CT scan.

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Summary Paroxysmal trigeminal neuralgia still remains a difficult condition to treat. Carbamazepine (Tegretol) has been a first line treatment, failing this surgery becomes necessary. However, many surgical procedures result in permanent sensory loss. Peripheral cryotherapy, along with the recently described ]annetta (1976) and Hakanson (1981) techniques, attempt to preserve sensation. Cryotherapy to 53 branches of the trigeminal nerve in 39 patients, who were followed up for 4 years, resulted in pain relief out-lasting return of sensation. These cases show that cryotherapy applied to the correctly located affected nerve branches can produce results which are unobtainable by other methods of pain control in paroxysmal trigeminal neuralgia.

Key-Words Paroxysmal trigeminal neuralgia - Cryotherapy Cryosurgery - Facial pain - Carbamazepine - Followup.

8. Complete abolition of pain by local anaesthetic injection into the trigger zone or by a regional nerve block. 9. Symptomatic relief with a therapeutic trial of carbamazepine (Tegretol). All patients had become intolerant or unresponsive to medication and those with atypical clinical features were excluded. Mean age was 54 years (range 18-76 years) and none had undergone neurosurgical procedures or neurolytic injections. Patients had had the condition for an average of 4.8 years (range 1 month to 20 years).

Cryotherapy Technique Identification of the affected branch, or branches, was achieved prior to cryotherapy, by local anaesthesia. Pain abolition by this procedure was the criterion for cryotherapy. The affected nerves were exposed under local anaesthesia and intravenous sedation (Diazepam). The infra-orbital nerve was approached by a Caldwell-Luc incision and reflection of a muco-periosteal flap up to the infraorbital foramen. A low buccal incision in the premolar region exposed the mental nerve. The long buccal nerve was found by dissection in the retromolar area and several branches were frequently identified. Exposed nerves were frozen with the DFS-30 system" (liquid nitrogen) which was thermostatically controlled at -120°C. A cycle of a 2 minute freeze followed by a 5 minute thaw was performed 3 times, taking care not to crush the nerve. If 2 branches were affected both were treated simultaneously, (most commonly the long buccal and mental nerves).

Results Thirty nine patients had a total of 53 open nerve freezes. Twenty five had only one nerve treated and 14 more than one (Table 1). Normal subjective and objective sensation to standard clinical tests returned within 3 months of cryotherapy in all patients. The pain control period (PCP) was * Spembly, Guitdford, Surrey, England

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J. max.-fac. Surg. 14 (1986)

Joanna M. Zakrzewska et al.

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deemed to have ended when either pain was reported or a trigger zone was found in the mucocutaneous distribution of the treated nerve. The PCP of individual nerves is seen in Figure 1. After one year 84 % of all treated nerves were pain free, falling to 32 % at 4 years. (Table 1). During the 4 year period 32 patients reported a "recurrence" of pain (Figure 2). Further examination showed that it was not necessarily in the distribution of the treated nerve but in an untreated area in 59 % of patients. The difference between the total PCP and individual nerve PCP is explained on the basis of pain migration. Nine patients had pain in an untreated branch within the same division and 10 developed pain in an ipsilateral untreated division (Table 2). Analysis of Table 2 shows that migration, if it is to occur, tends to present early. Discussion

The introduction of carbamazepine (Tegretol) by Blom in 1962 was a major breakthrough and it has become accepted as first line management. A1-Ubaidy and Nally (1976) found it initially effective in 84 % of 120 patients. Taylor et al. (1981) reported it effective in 69 % of 143 patients falling to 56 % in the long term. However, some patients become intolerant or unresponsive and although phenytoin (Dilantin) (lannone et al. 1958) and baclofen (Fromrn et al. 1984) are useful adjuncts, there is ultimately no alternative to surgery for them. The large number of available neurosurgical procedures underlines the fact that no single technique can ensure pain relief in every case. Radiofrequency thermocoagulation of the Gasserian ganglion was introduced by Sweet and Wepsic (1974) and remains the most popular technique. It was devised in an attempt selectively to destroy small fibres and to prevent total hemifacial anaesthesia. However, the recurrence rate correlates inversely with the coagulation Table 1 Nerve

Total Pain Control Period, 39 Patients.

temperature and the degree of post-operative facial sensory impairment (Salar et al. 1983). Morley (1977) stated that it is ineffective in the long term unless total anaesthesia in the affected area is induced. Nugent (1982) observed a 23 % recurrence rate in 800 procedures in 643 patients who had a mean follow up of 4 years. It is, however, simpler than retrogasserian rhizotomy popularized by Frazier (1925) and Dandy (1929), or microvascular decompression (Jannetta 1976). All involve major neurosurgery. The Hakanson's technique (1981) o f percutaneous retrogasserian glycerol rhizotomy has shown encouraging initial results (Lunsford and Bennett 1984) but long term follow up figures are not yet available. Cryotherapy could be an important alternative in management in the majority of patients but it does not purport to be curative. Experimental work shows that following cryotherapy to peripheral nerves, secondary nerve damage occurs (Sunderland's classification 1978). The connective tissue sheath is resistant and maintains a structural framework for regeneration (Carter et al. 1972). Whittaker (1974) in animal studies showed that large myelinated fibres were more susceptible to cryogenic insults. The effectiveness of cryotherapy lends support to the model for PTN proposed by Calvin et al. (1977) and Calvin (1979), which suggested that the primary pathology could be in the large fibres. Histological recovery studies (Mira 1979) indicate that the number of regenerated fibres are either the same, or e v e n increased, but with differences in fibre diameter, and also that repeated cryotherapy does not inhibit proximal stump regeneration. Cryogenic nerve blockade is a reversible, repeatable procedure and this is borne out clinically (Nally et al. 1984). Because of this there has been no permanent anaesthesia, anaesthesia dolorosa, or neuroma formation in this series. Nerve damage occurs at temperatures of - 2 0 ° C or below (Gaster et al. 1971). However, we feel that in the clinical

Analysis of Pain Relief Following 53 Procedures in 39 Patients. Number of Proced u res Number

%

Pain Control Periods 2 Years 3 Years Number % Number %

1 Year

4 Years Number %

Mental Buccal Infra-orbital

15 11 27

13 10 22

86 91 82

8 5 19

54 45 70

6 3 11

40 27 40

4 3 10

27 27 37

Total

53

45

84

32

60

20

38

17

32

Cryotherapy in the Management of Paroxysmal Trigeminal Neuralgia. Table 2

Site of Pain in 32 Patients after primary Procedure.

Pain control period months

0-5 6-11 12-17 18-23 24-35 36-48 Total

Pain recurrence Pain presenting in treated in untreated branch branch in same division 0 3 4 3 1 2 13 (41%)

3 6 0 0 0 0 9 (28%)

Pain presenting in untreated branch in another division 4 2 2 2 0 0 10 (31%)

situation cold is dissipated rapidly when the cryoprobe is in position and that a thermostatically controlled temperature of -120°C and nerve isolation are important to ensure a complete cryolesion with pan-necrosis. This series shows that pain migration is an important factor in assessing the effectiveness of cryotherapy. Commonly, pain migrates to anatomically distinct nerve branches. Interestingly pain in the lingual nerve is rare as an initial presentation but is increasingly diagnosed in post cryotherapy patients. Divisonal freezes are being undertaken on the basis of this observation. The development of the newer Jannetta (1976) and Hakanson (1981) techniques underline the desirability of preserving facial sensation and improving the quality of life for patients with PTN. The initial results are not as effective as the standard procedures of rhizotomy and radiofrequency thermocoagulation but, as Lunsford and Bennett (1984) point out, evaluation of less destructive procedures is still indicated. Tew and Van Loveren in commenting on Lunsford and Bennett's paper (1984) stated that the ideal treatment for PTN requires "the relief of pain without sensory loss, without significant surgical risk and without the side effects of long term medical treatment". Peripheral nerve cryotherapy has an important place to take in the management of patients in whom medical treatment has failed and major surgery is contra-indicated or undesirable since it is the simplest, safest effective technique yet described. There has been no mortality in this series and morbidity is low, being the same as for any other minor oral surgery procedure. Conclusion Initial work shows that cryotherapy is effective in the management of PTN. Further studies are currently being carried out to evaluate long term efficacy both in terms of pain relief and quality of life and its relation to carbamazepine therapy and radiofrequency thermocoagulation. Acknowledgement

We are grateful to E. Dawes for her secretarial assistance.

J. max.-fac. Surg. 14 (1986)

Barnard, J. D. W., J. W. Lloyd, C. J. Glynn: Cryosurgery in the management of intractable facial pain. Br. J. Oral Surg. 16 (1978-79) 135 Blom, S.: Trigeminat neuralgia: its treatment with a new anticonvulsant drug (G32883). Lancet 1 (1962) 839 Calvin, W. H.: Some design features of axons and how neuralgias may defeat them. In: J. J. Bonica et aL: Advances in Pain Research and Therapy, Vol. 3. Raven Press, New York (1979) 297 Calvin, W. H., J. D. Loeser, J. F. Howe: A neurophysiological theory for the pain mechanism of tic doloureux. Pain 3 (1977) 147 Carter, D. C., P. W. P. Lee, W. Gill, R. J. Johnston: The effects of cryosurgery on peripheral nerve function. J. R. Coll. Surg. Edin. 17 (1972) 25 Dandy, W. E.: An operation for the cure of tic doloureux: partial section of the sensory root at the pons. Arch. Surg. 18 (1929) 687 Frazier, C. H.: Subtotal resection of sensory root for relief of major trigeminal neuralgia. Arch. NeuroL Psychiatry 13 (1925) 378 Fromm, G. H., C. F. Terrence, A. S. Chattha: Baclofen in the treatment of trigeminal neuralgia: double-blind study and tong term follow up. Ann. Neurol. 15 (1984) 240 Gaster, R. N., T. M. Davidson, R. W. Rand, E. W. Fonkalsrud: Comparison of nerve regeneration rates following controlled freezing or crushing. Arch. Surg. 103 (1971) 378 Gregg, J. M., T. Banerjee, J. N. Ghia, R. Campbell: Radiofrequency tbermoneurolysis of peripheral nerves for control of trigeminal neuralgia. Pain 5 (1978) 231 Hakanson, S.: Trigeminal neuralgia treated by the injection of glycerol into the trigeminal cistern. Neurosurgery 9 (1981) 638 Iannone, A., A. B. Baker, F. Morrell: Dilantin in the treatment of trigeminal neuralgia. Neurology (Minneapolis) 8 (1958) 126 Jannetta, P. J.: Microsurgical approach to the trigeminal nerve for tic doloureux. Prog. Neurol. Surg. 7 (1976) 180 Lloyd, J. W., J. D. W. Barnard, C. J. Glynn: Cryoanalgesia. A new approach to pain relief. Lancet II (1976) 932 Lunsford, L. D., M. H. Bennett: Percutaneous retrogasserian glycerol rhizotomy for tic doloureux: Part 1: Technique and results in 112 patients. Neurosurgy. 14 (1984) 424 Mira, J. D.: Quantitative studies of the regeneration of rat myelinated nerve fibres: variations in the number and size of regenerating fibres after repeated localised freezings. J. Anat. 129 (1979) 77 Morley, T. P.: Place of peripheral and subtemporal ablative operations in the treatment of trigeminal neuralgia (tic doloureux). Clin. Neurosurg. 24 (1977) 550 Nally, F. F.: A 22-year study of paroxysmal trigeminal neuralgia in 211 patients with a 3-year appraisal of the role of cryotherapy. Oral Surg. 58 (1984) 17 Nally, F. F., S. R. Flint, S. D. Bennett, F. S. Talhi: The role of cryotherapy in the management of paroxysmal trigeminal neuralgia - an analysis of 112 patients. J. Irish Coll. Physic. Surg. 13 (1984) 184 Nugent, G. R.: Technique and results of 800 percutaneous radiofrequency thermocoagulations for trigeminal neuralgia. Appl. Neurophysiol. 45 (1982) 504 Salar, G., S. Mingrino, L lob: Alterations of facial sensitivity induced by percutaneous thermocoagulation for trigeminal neuralgia. Surg. Neurol. 19 (1983) 126 Sweet, W. H., J. G. Wepsic: Controlled thermocoagulation of trigeminal ganglion and rootlets for differential destruction of pain fibres. Part 1: Trigeminal neuralgia. J. Neurosurg. 39 (1974) 143 Sunderland, S.: Cooling and freezing. In: Nerves and nerve injuries. Livingstone, Edinburgh 1978, 163 Taylor, J C., S. Brauer, M. L. E. Espir: Long-term treatment of trigeminal neuralgia with carbamazepine. Post. Med. J. 57 (1981) 16 Whittaker, D. K.:Degeneration and regeneration of nerves following cryosurgery. Br. J. Exp. Path. 55 (1974) 595

References

AI-Ubaidy, S. S., F. F. Nally: Adverse reactions to carbamazepine (Tegretol). Br. J. Oral Surg. 13 (1976) 289 Barnard, D., J. Lloyd, J. Evans: Cryoanalgesia in the management of chronic facial pain. J. Max.-Fac. Surg. 9 (1981) 101

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Joanna M. Zakrzewska, MB, BChir, BDS, FDSRCS (Eng) Department of Oral Medicine Eastman Dental Hospital 256 Gray's Inn Road London WC1X 8LD, Great Britain