Stereotactic mesencephalotomy for cancer - related facial pain

Neurosurgical Treatment of Pain

The aim of this review is to draw attention to neurosurgical approaches for treating chronic and opioid-resistant pain. In a first chapter, an up-to-date overview of the main pathophysiological mechanisms of pain has been carried out, with special emphasis on the details in which the surgical treatment is based. In a second part, the principal indications and results of different surgical approaches are reviewed. Cordotomy, Myelotomy, DREZ lesions, Trigeminal Nucleotomy, Mesencephalotomy, and Cingulotomy are revisited. Ablative procedures have a limited role in the management of chronic non-cancer pain, but they continues to help patients with refractory cancer-related pain. Another ablation lesion has been named and excluded, due to lack of current relevance. Peripheral Nerve, Spine Cord, and the principal possibilities of Deep Brain and Motor Cortex Stimulation are also revisited. Regarding electrical neuromodulation, patient selection remains a challenge.

Semidirect targeting-based stereotactic mesencephalotomy for the treatment of refractory pain: a case series

OBJECTIVE

One of the few resources for treating medically intractable pain is ablative surgery, but its indications have fallen dramatically over the last decades. One such procedure is mesencephalotomy. This study aims to determine current risks and benefits of MR-guided semidirect targeting-based stereotactic mesencephalotomy.

METHODS

This was a retrospective study based on a review of the medical records of 22 patients with nociceptive (n = 5), neuropathic (n = 10), or mixed (n = 7) refractory pain treated with unilateral mesencephalotomy alone (17 patients) or associated with bilateral anterior cingulotomy (5 patients) between 2014 and 2021 in the authors' institutions. The confidence interval adopted in this study was 95%.

RESULTS

The sample included 12 women and 10 men with ages ranging from 23 to 80 years (mean 55.1 ± 17.1 years). Using MR-guided semidirect targeting, the following structures were targeted: spinoreticulothalamic (neuropathic/mixed pain, n = 17), trigeminothalamic (nociceptive/mixed pain in the face, n = 5), and neospinothalamic (nociceptive/mixed pain in the body, n = 7) pathways. The most common response to macrostimulation was central heat/moderate discomfort. Radiofrequency thermocoagulation was made with 70°C-75°C/60 sec. A total of 86.3% (3 months) and 76.9% (12 months) of the patients achieved excellent or good results (improvement of pain > 50%), presenting with a significant mean pain relief of 80.1% at 3 months and 71.4% at 12 months postoperatively. The addition of bilateral anterior cingulotomy did not improve the results. Patients with upper limb, cervicobrachial, and face pain did significantly better than those with trunk pain. The worst results were seen in patients with neuropathic and/or trunk pain. The surgical failure (pain relief ≤ 25%) and recurrence rates were 9.1% each, apparently related to the use of lower lesioning parameters (70°C/60 sec) and to the presence of neuropathic and/or trunk pain. The morbidity rate was 8%, with both complications (vertical diplopia and confusion/agitation) happening in patients lesioned with 75°C/60 sec. There were no deaths in this series.

CONCLUSIONS

These results show that contemporary stereotactic mesencephalotomy is an effective, relatively low-risk, and probably underused procedure for treating medically intractable pain. Careful semidirect determination of the target coordinates associated with close attention to electrical macrostimulation responses certainly plays an important role in avoiding complications in most of the procedures. A higher lesioning temperature (75°C) apparently prevents recurrence, but at the cost of an increased risk of complications.

Neurosurgical ablative procedures for intractable cancer pain

OBJECTIVE

Cancer patients suffering from severe refractory pain may benefit from targeted ablative neurosurgical procedures aimed to disconnect pain pathways in the spinal cord or the brain. These patients often present with a plethora of medical problems requiring careful consideration before surgical interventions. The authors present their experience at an interdisciplinary clinic aimed to facilitate appropriate patient selection for neurosurgical procedures, and the outcome of these interventions.

METHODS

This study was a retrospective review of all patients who underwent neurosurgical interventions for cancer pain in the authors' hospital between March 2015 and April 2018. All patients had advanced metastatic cancer with limited life expectancy and suffered from intractable oncological pain.

RESULTS

Sixty patients underwent surgery during the study period. Forty-three patients with localized pain underwent disconnection of the spinal pain pathways: 34 percutaneous-cervical and 5 open-thoracic cordotomies, 2 stereotactic mesencephalotomies, and 2 midline myelotomies. Thirty-nine of 42 patients (93%) who completed these procedures had excellent immediate postoperative pain relief. At 1 month the improvement was maintained in 30/36 patients (83%) available for follow-up. There was 1 case of hemiparesis.Twenty patients with diffuse pain underwent stereotactic cingulotomy. Nineteen of these patients reported substantial pain relief immediately after the operation. At 1 month good pain relief was maintained in 13/17 patients (76%) available for follow-up, and good pain relief was also found at 3 months in 7/11 patients (64%). There was no major morbidity or mortality.

CONCLUSIONS

With careful patient selection and tailoring of the appropriate procedure to the patient's pain syndrome, the authors' experience indicates that neurosurgical procedures are safe and effective in alleviating suffering in patients with intractable cancer pain.

Ablative brain surgery: an overview

Background: Ablative therapies have been used for the treatment of neurological disorders for many years. They have been used both for creating therapeutic lesions within dysfunctional brain circuits and to destroy intracranial tumors and space-occupying masses. Despite the introduction of new effective drugs and neuromodulative techniques, which became more popular and subsequently caused brain ablation techniques to fall out favor, recent technological advances have led to the resurgence of lesioning with an improved safety profile. Currently, the four main ablative techniques that are used for ablative brain surgery are radiofrequency thermoablation, stereotactic radiosurgery, laser interstitial thermal therapy and magnetic resonance-guided focused ultrasound thermal ablation. Object: To review the physical principles underlying brain ablative therapies and to describe their use for neurological disorders. Methods: The literature regarding the neurosurgical applications of brain ablative therapies has been reviewed. Results: Ablative treatments have been used for several neurological disorders, including movement disorders, psychiatric disorders, chronic pain, drug-resistant epilepsy and brain tumors. Conclusions: There are several ongoing efforts to use novel ablative therapies directed towards the brain. The recent development of techniques that allow for precise targeting, accurate delivery of thermal doses and real-time visualization of induced tissue damage during the procedure have resulted in novel techniques for cerebral ablation such as magnetic resonance-guided focused ultrasound or laser interstitial thermal therapy. However, older techniques such as radiofrequency thermal ablation or stereotactic radiosurgery still have a pivotal role in the management of a variety of neurological disorders.

Contemporary concepts of pain surgery

Pain surgery is one of the historic foundations of neurological surgery. The authors present a review of contemporary concepts in surgical pain management, with reference to past successes and failures, what has been learned as a subspecialty over the past 50 years, as well as a vision for current and future practice. This subspecialty confronts problems of cancer pain, nociceptive pain, and neuropathic pain. For noncancer pain, ablative procedures such as dorsal root entry zone lesions and rhizolysis for trigeminal neuralgia (TN) should continue to be practiced. Other procedures, such as medial thalamotomy, have not been proven effective and require continued study. Dorsal rhizotomy, dorsal root ganglionectomy, and neurotomy should probably be abandoned. For cancer pain, cordotomy is an important and underutilized method for pain control. Intrathecal opiate administration via an implantable system remains an important option for cancer pain management. While there are encouraging results in small case series, cingulotomy, hypophysectomy, and mesencephalotomy deserve further detailed analysis. Electrical neuromodulation is a rapidly changing discipline, and new methods such as high-frequency spinal cord stimulation (SCS), burst SCS, and dorsal root ganglion stimulation may or may not prove to be more effective than conventional SCS. Despite a history of failure, deep brain stimulation for pain may yet prove to be an effective therapy for specific pain conditions. Peripheral nerve stimulation for conditions such as occipital neuralgia and trigeminal neuropathic pain remains an option, although the quality of outcomes data is a challenge to these applications. Based on the evidence, motor cortex stimulation should be abandoned. TN is a mainstay of the surgical treatment of pain, particularly as new evidence and insights into TN emerge. Pain surgery will continue to build on this heritage, and restorative procedures will likely find a role in the armamentarium. The challenge for the future will be to acquire higher-level evidence to support the practice of surgical pain management.

Stereotactic mesencephalotomy for palliative care pain control: A case report, literature review and plea to rediscover this operation

Introduction Stereotactic mesencephalotomy is an ablative procedure which lesions the pain pathways (spinothalamic and trigeminothalamic tracts) at the midbrain level to treat medically refractory, nociceptive, contralateral pain. Sparsely reported in contemporary English language literature, this operation is at risk of being lost from the modern-day neurosurgical practice. Methods We present a case report and brief review of the literature on stereotactic mesencephalotomy. A 17-year-old girl with cervical cord glioblastoma and medically refractory unilateral head and neck pain was treated with contralateral stereotactic mesencephalotomy. The lesion was placed at the level of the inferior colliculus, half way between the lateral edge of the aqueduct and lateral border of the midbrain. Results The patient had no head and neck pain immediately after the procedure and remained pain-free for the remainder of her life (five months). She was weaned off her pre-operative narcotics and was able to leave hospital, meeting her palliative care goals. Conclusions Cancer-related unilateral head and neck nociceptive pain in the palliative care setting can be successfully treated with stereotactic mesencephalotomy. We believe that stereotactic mesencephalotomy is the treatment of choice for a small number of patients typified by our case. The authors make a plea to the palliative care and neurosurgical communities to rediscover this operation.