Surface reconstruction from routine CT-scan shows large anatomical variations of falx cerebri and tentorium cerebelli.

BACKGROUND: Finite element modeling of the human head offers an alternative to experimental methods in understanding the biomechanical response of the head in trauma brain injuries. Falx, tentorium, and their notches are important structures surrounding the brain, and data about their anatomical variations are sparse. OBJECTIVE: To describe and quantify anatomical variations of falx cerebri, tentorium cerebelli, and their notches. METHODS: 3D reconstruction of falx and tentorium was performed by points identification on 40 brain CT-scans in a tailored Matlab program. A scatter plot was obtained for each subject, and 8 anatomical landmarks were selected. A reference frame was defined to determine the coordinates of landmarks. Segments and areas were computed. A reproducibility study was done. RESULTS: The height of falx was 34.9 ± 3.9 mm and its surface area 56.5 ± 7.7 cm2. The width of tentorium was 99.64 ± 4.79 mm and its surface area 57.6 ± 5.8 cm2. The mean length, height, and surface area of falx notch were respectively 96.9 ± 8 mm, 41.8 ± 5.9 mm, and 28.8 ± 5.8 cm2 (range 15.8-40.5 cm2). The anterior and maximal widths of tentorial notch were 25.5 ± 3.5 mm and 30.9 ± 2.5 mm; its length 54.9 ± 5.2 mm and its surface area 13.26 ± 1.6 cm2. The length of falx notch correlated with the length of tentorial notch (r = 0.62, P < 0.05). CONCLUSION: We observe large anatomical variations of falx, tentorium, and notches, crucial to better understand the biomechanics of brain injury, in personalized finite element models.

Ziconotide for spinal cord injury-related pain.

BACKGROUND: Central neuropathic pain related to spinal cord injury is notoriously difficult to treat. So far most pharmacological and surgical options have shown but poor results. Recently ziconotide has been approved for use both neuropathic and non-neuropathic pain. In this cohort study, we assessed responder rate and long-term efficacy of intrathecal ziconotide in patients with pain related to spinal cord injury. METHODS: Patients presenting chronic neuropathic related to spinal cord lesions that was refractory to medical pain management were considered for inclusion. Those accepting were tested by lumbar puncture injection of ziconotide or continuous intrathecal infusion and if a significant decrease in pain scores (>40%) was noted they were implanted with a continuous infusion pump. They were then followed up for at least 1 year with constant assessment of the evolution of pain and side effects. RESULTS: Out of the 20 patients tested 14 had a decrease in pain scores of more than 40% but only 11 (55%) were implanted with permanent pumps due to side effects and patient choice. These were followed up on average for 3.59 years (±1.94) and in eight patients an above threshold decrease in pain scores was maintained. Overall in patients that responded to the test baseline VAS was 7.91 and 4.31 at last follow-up with an average dose of 7.2 µg of ziconotide per day. Six patients (30%) did not respond to any test and in three patients side effects precluded pump implantation. No significant long-term effects of the molecule were noted. CONCLUSION: This study shows response to intrathecal ziconotide test in 40% of the patients of a very specific population in whom other therapeutic options are not available. This data justifies the development further studies such as a long-term randomized controlled trial. SIGNIFICANCE: Intrathecal Ziconotide is a posible alternative for the treatment of pain in patients with spinal cord injury and below level neuropathic pain.

Intracerebroventricular Pain Treatment with Analgesic Mixtures including Ziconotide for Intractable Pain.

Intracerebroventricular (ICV) administration of opioids for control of intractable cancer pain has been used since 1982. We present here our experience of intracerebroventricular administration of pain treatments including ziconotide associated with morphine and ropivacaine for patients resistant to a conventional approach, with nociceptive, neuropathic, or mixed pain. These clinical cases were conducted with patients suffering from refractory pain, more than 6/10 on a numerical pain rating scale (NPRS) while on high-dose medical treatment and/or intolerance with significant side effects from oral medication. The baseline study visit included a physical examination and an assessment of pain intensity on a NPRS. Under general anesthesia, a neuronavigation device was used to place the catheter on the floor of the third ventricle, supported by an endoscope. Then, drugs were injected in the cerebroventricular system, through a pump (external or subcutaneous). The primary objective was to measure pain evaluation with ICV treatment after a complete withdrawal of other medications.Four patients were enrolled: 3 with intractable cancer pain and one with central neuropathic pain. The median NPRS at baseline was 9.5 [8.5; 19]. The mean NPRS after one month was 3.5 [3; 4.5]. Ziconotide was initiated at 0.48 µg/d and up to a median of 1.2 µg/d [1.0; 1.56]. The median dose of morphine and ropivacaine used initially was respectively 0.36 mg/d [0.24; 0.66] up to 0.6 mg/d [0.45; 4.63] and 1.2 mg/d [0; 2.4] up to 2.23 mg/d [1.2; 3.35]. Minor side effects were initially observed but transiently. One psychiatric agitation required discontinuation of ziconotide infusion. For intractable pain, using ziconotide by intracerebroventricular infusion seems safe and efficient, specifically for chronic neoplastic pain of cervicocephalic, thoracic, or diffuse origin and also for pain arising from a central neuropathic mechanism.