Laser Interstitial Thermal Therapy for Posterior Fossa Lesions: An Initial Experience.

BACKGROUND: The application of laser interstitial thermal therapy (LITT) for intracranial lesions in the posterior fossa tumors remains challenging due to the smaller size of this compartment as well as the thickness and angle of the occipital bone. In this study, we reviewed our experience with this treatment modality for posterior fossa lesions. METHODS: We retrospectively reviewed our series of 8 patients with posterior fossa tumors treated with LITT from an Institutional Review Board-approved brain tumor database (2012-2017) of more than 200 cases at our institution. RESULTS: The 8 patients underwent LITT targeting 3 metastases, 2 pilocytic astrocytomas, 2 zones of radiation necrosis after radiosurgery, and 1 glioblastoma (GBM). The mean preoperative lesion volume was 4.35 cm3. A 6 months postsurgery, the mean lesion volume had decreased from 9.64 cm3 to 5.72 cm3. Two of the tumors (the GBM and a metastatic adenocarcinoma) progressed after 8.5 and 7.5 months, respectively, with mortality after 1.1 and 1.6 years, respectively. Surgical resection was performed in a patient with metastatic adenocarcinoma tumor at 7.7 months after LITT. All other lesions remained stable or were diminished at a median follow-up of 14.8 months (range, 0.4-37.5 months). Magnetic resonance imaging (MRI) on the first postoperative day, showed an increase in mean tumor-related edema volume from 9.45 cm3 to 14.10 cm3. After a postoperative follow-up of at least 1 month, this mean decreased to 8.70 cm3. One case each of transient partial unilateral sixth cranial nerve palsy, superficial wound infection, and a late obstructive hydrocephalus were noted postoperatively. No mortality was associated with the procedure. CONCLUSIONS: LITT is a safe and feasible treatment modality even in challenging locations like the posterior fossa. However, surgical indications should be tailored for each individual patient based on the size and location of tumor.

Magnetic Resonance Thermometry and Laser Interstitial Thermal Therapy for Brain Tumors.

Recent technological advancements in intraoperative imaging are shaping the way for a new era in brain tumor surgery. Magnetic resonance thermometry has provided intraoperative real-time imaging feedback for safe and effective application of laser interstitial thermal therapy (LITT) in neuro-oncology. Thermal ablation has also established itself as a surgical option in epilepsy surgery and is currently used in spine oncology with promising results. This article reviews the principles and rationale as well as the clinical application of LITT for brain tumors. It also discusses the technical nuances of the current commercially available systems.

Sandwich technique, peripheral nerve stimulation, peripheral field stimulation and hybrid stimulation for inguinal region and genital pain.

OBJECTIVE: Ilioinguinal neuralgia (IG) and genitofemoral (GF) neuralgia following inguinal hernia repair is a chronic and debilitating neuropathic condition. Recently, peripheral nerve stimulation has become an effective and minimally invasive option for the treatment of refractory pain. Here we present a retrospective case series of six patients who underwent placement of peripheral nerve stimulation electrodes using various techniques for treatment of refractory post-intervention inguinal region pain. METHODS: Six patients with post-intervention inguinal, femoral or GF neuropathic pain were evaluated for surgery. Either octopolar percutaneous electrodes or combination of paddle and percutaneous electrodes were implanted in the area of their pain. Pain visual analog scores (VAS), surgical complication rate, preoperative symptom duration, degree of pain relief, preoperative and postoperative work status, postoperative changes in medication usage, and overall degree of satisfaction with this therapy was assessed. RESULTS: All six patients had an average improvement of 62% in the immediate post-operative follow-up. Four patients underwent stimulation for IG, one for femoral neuralgia, and another for GF neuralgia. Peripheral nerve stimulation provided at least 50% pain relief in all the six patients with post-intervention inguinal region pain. 85% of patients indicated they were completely satisfied with the therapy overall. There was one treatment failure with an acceptable complication rate. CONCLUSION: Peripheral nerve or field stimulation for post-intervention inguinal region pain is a safe and effective treatment for this refractory and complex problem for patients who have exhausted other management options.

Peripheral field stimulation for thoracic post herpetic neuropathic pain.

OBJECTIVE: Post herpetic neuralgia is a chronic, debilitating pain with very few management options and is often refractory to treatment. We present our experience with a series of 4 patients who underwent subcutaneous peripheral field stimulation for treatment of thoracic post herpetic neuropathic pain. METHODS: Four patients with intractable thoracic post herpetic neuropathic pain were operated after maximum medical treatment and a neuropsychological evaluation. Multiple percutaneous electrodes were placed in the subcutaneous plane in the region of pain for a 7-day trial. Following a successful trial (more than 50% reduction of pain), the electrodes were then internalized and attached to a pulse generator. Visual analog scores (VAS) were studied during the preoperative, immediate postoperative and last follow-up visits. Long-term treatment results were determined by retrospective review of medical records. Average follow-up period was 28.2 months. RESULTS: All 4 patients showed persistent improvement in their VAS pain scores with an average improvement of more than 75%. There were no treatment failures and no complication requiring re-operation was reported. CONCLUSION: Peripheral field stimulation for the treatment of post herpetic neuropathic pain is a safe and effective method for pain relief for an extremely complex problem with very few solutions. Patient selection and proper lead placement is most important for the success of treatment.

Surgical options for complex craniofacial pain.

Complex craniofacial pain can be a challenging condition to manage both medically and surgically, but there is a resurgence of interest in the role of neurostimulation therapy. Surgical options for complex craniofacial pain syndromes include peripheral nerve/field stimulation, ganglion stimulation, spinal cord stimulation, dorsal nerve root entry zone lesioning, motor cortex stimulation, and deep brain stimulation. Peripheral nerve/field stimulation is rapidly being explored and is preferred by both patients and surgeons. Technological advances and improved understanding of the interactions of pain pathways with its affective component will widen the scope of neurostimulation therapy for craniofacial pain syndromes.

Technological innovations in implants used for pain therapies.

The field of pain management has experienced tremendous growth in implantable therapies secondary to the innovations of bioengineers, implanters, and industry. Every aspect of neuromodulation is amenable to innovation from implanting devices to anchors, electrodes, programming, and even patient programmers. Patients with previously refractory neuropathic pain syndromes have new and effective pain management strategies that are a direct result of innovations in implantable devices.

Peripheral nerve stimulation by 'sandwich' paddle leads: technical note.

BACKGROUND: Recently, there has been a burgeoning interest in the utility of peripheral nerve stimulation (PNS) for a variety of chronic focal neuropathic, musculoskeletal and visceral pain conditions. If the source of pain is directly related to a single peripheral nerve, surgical exposure and placing a paddle lead on the nerve are most effective. METHODS: In this report, we describe a novel technique that optimizes the peripheral nerve stimulation by two paddle leads placed on either side of the nerve with their stimulating surfaces in contact with the nerve. After appropriate prepping and draping, the selected nerve is localized and circumferentially dissected free from the adjacent soft tissue. There should be enough length of nerve to accommodate two On-Point quadripolar leads (Medtronic, MN) along the length of the nerve in the same direction. RESULTS: This 'sandwich' technique provides a wider interface of contacts with nerve fibers. It reduces the chance of migration and provides an opportunity for 'crosstalk.' CONCLUSION: In selected cases where an open surgical PNS lead needs to be placed, the 'sandwich' technique can be used to augment the stimulation without additional morbidity. Although occasionally used in practice, this technique is still unreported.