Facial pain due to vascular lesions of the brain stem relieved by dorsal root entry zone lesions in the nucleus caudalis. Report of two cases

Episodic pain syndrome restricted cheiro-oral region associated with pontine lesion

Other than from the thalamus and sensory cortex, episodic pain is an extremely rare neurological manifestation in the central compartment. This study reports a middle-aged man who experienced an acute onset of episodic oscillatory burning pain restricted to the cheiro-oral region, who was found to have a singular infarct at the left tegmental pons. A close relationship between his pain attack and an elevation of arterial blood pressure was clearly observed. Blood adenohypophyseal hormones and electroencephalogram did not reveal an abnormality in the ictus. Neuroimaging and clinical studies did not support involvement of the thalamus, periaqueductal gray matter, hypothalamus or regional structure. Therefore, episodic pain may be an isolated manifestation with a pontine lesion. A relapsing expansion of focal cerebral oedema with fluid retention may have corresponded to the oscillation of his sensory deficit. This accumulating, devastating calamity by a repetitive and paroxysmal offense after a blood-brain barrier breakdown should be cautiously reviewed.

Trigeminal nucleus caudalis dorsal root entry zone radiofrequency thermocoagulation for invalidating facial pain

INTRODUCTION

Facial pain syndromes occasionally result in desperate clinical settings completely unresponsive to any known therapy. Trigeminal nucleus caudalis dorsal root entry zone (DREZ) lesion is reported to be of benefit in such cases. In 1982 Nashold performed the first DREZ caudalis lesion in a patient with anaesthesia dolorosa.

PATIENTS AND METHODS

From 1994 to 2002 we have performed six DREZ caudalis lesions on five patients with extremely invalidating facial pain resistant to multiple pharmacological and surgical therapies. Pain was secondary to previous craniofacial surgery in all but one case. Pain presented as anaesthesia dolorosa or atypical facial pain so severe as to interfere with personal hygiene and even to prevent patients from oral feeding. A midline suboccipital approach was used and radiofrequency lesions (at the trigeminal nucleus caudalis in the cervicomedullary junction) were made at 1-mm intervals, 75 (o)C for 15 seconds each along the ipsilateral posterolateral sulcus from the cervical DREZ up to the obex.

RESULTS

Pain relief was complete and permanent in two patients. Three patients experienced significant improvement but pain recurred in two (weeks to a few months after the procedure). No patient's pain was made worse. A patient with persistent postoperative nasolabial pain was re-operated on (improving again but ultimately remaining unchanged). Air venous embolism related to the sitting position (3 patients) during surgery and bradycardia due to manipulation in medulla (2 patients) occurred during some of the procedures without any cardiovascular or neurological repercussion. Postoperative complications included mild and transient ataxia and monoparesia (3 patients).

DISCUSSION

Facial pain secondary to craniofacial surgery is known to be among the least responsive to treatment and a true challenge for pain clinicians. Actual indications for this procedure, operative technical details and the results of our series compared to previous reports are reviewed.

CONCLUSION

Trigeminal nucleus caudalis radiofrequency thermocoagulation is an effective neurosurgical procedure for the treatment of chronically debilitating and desperate facial pain syndromes with acceptable morbidity.

Trigeminal neuralgia and other neuropathic pain syndromes of the head and face

Trigeminal neuralgia is the most common craniofacial pain syndrome of neuropathic origin. Although the diagnosis remains based exclusively on history and symptomatology, modern diagnostic techniques, particularly high-resolution magnetic resonance imaging, provides valuable new insight into the pathophysiology of these cases with additional implications for therapeutic strategies. Other neuropathic syndromes affect the trigeminal nerve and warrant different treatments with varied rates of success. Rarely, neuralgias of other cranial nerves mimic trigeminal neuralgia. Finally, it is imperative to distinguish atypical facial pains from these neuropathic syndromes to avoid unsuccessful therapies.

Dorsal root entry zone lesions for intractable pain after trauma to the conus medullaris and cauda equina

This review was undertaken to determine the efficacy of using dorsal root entry zone (DREZ) lesions to treat intractable pain caused by trauma to the conus medullaris and cauda equina. Traumatic lesions of this area are unique in that both the spinal cord and the peripheral nerve roots are injured. Although DREZ lesions have been shown to relieve pain of spinal cord origin in many patients, they have been shown not to relieve pain of peripheral nerve origin. Therefore, 39 patients with trauma to the conus medullaris and cauda equina who underwent DREZ lesioning for intractable pain were reviewed retrospectively. The results of this review demonstrate the efficacy of DREZ lesions in these patients. At a mean follow-up period of 3.0 years, 54% of patients were pain-free without medications, and 20% required only nonnarcotic analgesic drugs for pain that no longer interfered with their daily activities. Better outcomes were noted in patients with an incomplete neurological deficit, with pain having an "electrical" character, and with injuries due to blunt trauma. Operative complications included weakness (four patients), bladder or sexual dysfunction (three), cerebrospinal fluid leak (two), and wound infection (two), but overall, 79.5% of patients (31 of 39) were without serious complications. Complications were limited to patients with prior tissue damage at the surgical exploration site and were most prevalent in patients who underwent bilateral DREZ lesions. In conclusion, this preliminary report suggests that DREZ lesions may be useful in combating intractable pain from traumatic injuries to the conus medullaris and cauda equina, with some risk to neurological function that may be acceptable in this group of patients.

The Duke experience with the nucleus caudalis DREZ operation

The nucleus caudalis DREZ operation has been performed in three phases at Duke. Between 1982 and 1988 radiofrequency (RF) lesions were made in the trigeminal nucleus extending from the C2 root to the obex using a straight electrode. Complications include ipsilateral arm ataxia due to spinocerebellar tract injury and ipsilateral lower limb weakness from the pyramidal tract. The former occurred at least transiently in 90% of cases. The electrode employed from 1988 to 1989 had proximal insulation protecting the spinocerebellar tract. Since 1989 a ninety degree bend has been added to the electrode to allow better placement. Two electrodes are used to accommodate the shape of the caudalis nucleus. A total of 101 procedures have been performed. The newest electrodes were used in 46 procedures. Ataxia is recognized in 39%. Overall pain relief was excellent in 34% and good in 40%. In post herpetic neuralgia 71% enjoyed excellent or good relief. Indications include post herpetic neuralgia, deafferentation pain (anaesthesia dolorosa, post-tic dysesthesia, stroke, MS, gasserian tumour, Gamma Knife radiation injury), facial trauma/surgery, atypical facial pain, and migraine/cluster headache. A study to compare this operation to deep brain stimulation prospectively for the above indications has been initiated.

Ultrasonic lesion of the trigeminal nucleus caudalis for deafferentation facial pain

The deafferentation facial pain syndrome, caused by physical, herpetic or tumourous lesions of the trigeminal sensory root, was successfully managed with ultrasonic trigeminal nucleotomy. The article presents this new surgical technique and its results in 14 patients suffering from severe facial pain and dysaesthesias.