Nerve blocks

Local and regional analgesia, achieved by injecting a local anesthetic into tissues, or in proximity to certain parts of the peripheral nervous system, or into the epidural/subarachnoid space, to relieve pain has been used widely for many years. While nerve blocks no longer have the preeminent role as the pain management in cancer patients, they will remain useful tools in managing pain and increasing 'quality of life' of the cancer patients, only if they properly applied. The purpose of this chapter is to present an updated version of the regional analgesia in cancer pain management.     

Vagus Nerve and Vagus Nerve Stimulation,a Comprehensive Review: Part I

The vagus nerve (VN), the “great wondering protector” of the body, comprises an intricate neuro‐endocrine‐immune network that maintains homeostasis. With reciprocal neural connections to multiple brain regions, the VN serves as a control center that integrates interoceptive information and responds with appropriate adaptive modulatory feedbacks. While most VN fibers are unmyelinated C‐fibers from the visceral organs, myelinated A‐ and B‐fiber play an important role in somatic sensory, motor, and parasympathetic innervation. VN fibers are primarily cholinergic but other noncholinergic nonadrenergic neurotransmitters are also involved. VN has four vagal nuclei that provide critical controls to the cardiovascular, respiratory, and alimentary systems. Latest studies revealed that VN is also involved in inflammation, mood, and pain regulation, all of which can be potentially modulated by vagus nerve stimulation (VNS). With a broad vagal neural network, VNS may exert a neuromodulatory effect to activate certain innate “protective” pathways for restoring health.     

Nerve Stimulator-Guided Occipital Nerve Blockade for Postdural Puncture Headache

Postdural puncture headache (PDPH) is one of the most common complications of spinal anesthesia, where adequate hydration with bed rest in the horizontal position is the initial recommendation. Epidural blood patch is to date the most effective treatment, but it is an invasive procedure that may result in serious complications. The aim of the current study was to conduct a prospective, randomized, single-blinded comparison between bilateral occipital blockade and conventional expectant therapy in adults suffering from PDPH. A primary hypothesis was that occipital blockade would result in better pain management and quicker return to normal activity. Fifty adult patients diagnosed with PDPH were randomly divided into two equal groups of 25 each. All patients in the block group received greater and lesser occipital nerve blocks, whereas the control group received adequate hydration, complete bed rest, and analgesics. Forty-seven patients entered into the final analysis as three patients withdrew from study. Complete pain relief was achieved in 68.4% of block patients after 1 to 2 blocks, with 31.6% ultimately receiving up to 4 blocks. Visual analog scales were significantly lower in the block group ( P  < 0.01), and the block group consumed significantly less analgesics in the follow-up period ( P  < 0.05) compared with control group. Block patients had significantly shorter hospital stays and sick leave periods ( P  < 0.001). The studied method is superior to expectant conservative therapy in the treatment of patients suffering from PDPH.     

Vagus Nerve and Vagus Nerve Stimulation,a Comprehensive Review: Part II

The development of vagus nerve stimulation (VNS) began in the 19th century. Although it did not work well initially, it introduced the idea that led to many VNS‐related animal studies for seizure control. In the 1990s, with the success of several early clinical trials, VNS was approved for the treatment of refractory epilepsy, and later for the refractory depression. To date, several novel electrical stimulating devices are being developed. New invasive devices are designed to automate the seizure control and for use in heart failure. Non‐invasive transcutaneous devices, which stimulate auricular VN or carotid VN, are also undergoing clinical trials for treatment of epilepsy, pain, headache, and others. Noninvasive VNS (nVNS) exhibits greater safety profiles and seems similarly effective to their invasive counterpart. In this review, we discuss the history and development of VNS, as well as recent progress in invasive and nVNS.     

Vagus Nerve and Vagus Nerve Stimulation,a Comprehensive Review: Part III

Vagus nerve stimulation (VNS) is currently undergoing multiple trials to explore its potential for various clinical disorders. To date, VNS has been approved for the treatment of refractory epilepsy and depression. It exerts antiepileptic or antiepileptogenic effect possibly through neuromodulation of certain monoamine pathways. Beyond epilepsy, VNS is also under investigation for the treatment of inflammation, asthma, and pain. VNS influences the production of inflammatory cytokines to dampen the inflammatory response. It triggers the systemic release of catecholamines that alleviates the asthma attack. VNS induces antinociception by modulating multiple pain‐associated structures in the brain and spinal cord affecting peripheral/central nociception, opioid response, inflammation process, autonomic activity, and pain‐related behavior. Progression in VNS clinical efficacy over time suggests an underlying disease‐modifying neuromodulation, which is an emerging field in neurology. With multiple potential clinical applications, further development of VNS is encouraging.     

Effect of Parathyroid Hormone and Uremia on Peripheral Nerve Calcium and Motor Nerve Conduction Velocity

Peripheral neuropathy is not an uncommon complication of chronic uremia. Because parathyroid hormone, by raising brain calcium, is partly responsible for central nervous system aberrations in uremia, we studied the relative role of uremia, per se, and(or) parathyroid hormone on peripheral nerve calcium and motor nerve conduction velocity (MNCV). Studies were made in six groups of six dogs each, as follows: (a) normal dogs, (b) thyroparathyroidectomized (T-PTX) animals, (c) dogs with 3 days of uremia produced by bilateral nephrectomy, (d) T-PTX before the induction of acute renal failure, (e) normal dogs receiving 100 U/day of parathyroid extract (PTE) for 3 days, and (f) normal animals receiving 3 days of PTE followed by 5 days without PTE. Calcium content in peripheral nerve (expressed as milligram per kilogram of dry weight) was 252±5 (SE) in normal animals and 262±4 in T-PTX dogs. It was significantly (P < 0.01) higher in dogs with acute renal failure and intact parathyroid glands (410±12) and in normal animals receiving PTE (362±7). T-PTX, before acute renal failure, prevented the rise in peripheral nerve calcium (262±4) and PTE withdrawal was followed by the return of peripheral nerve calcium to normal (261±3). The increments in peripheral nerve calcium were associated with slowing of MNCV. It decreased significantly from 70±4 to 43±1 m/s after 3 days of acute uremia in dogs with intact parathyroid glands and T-PTX before acute renal failure prevented the fall in MNCV. Administration of PTE to normal animals reduced MNCV from 63±3 to 35±3 m/s and the withdrawal of PTE restored MNCV to normal (73±2 m/s). The results show that (a) excess parathyroid hormone increases peripheral nerve calcium and slows MNCV, (b) T-PTX, previously performed, prevents these changes in acute uremia, and (c) the withdrawal of PTE administration is followed by a reversal of the abnormalities.     

腓浅神经浅支移植修复桡神经缺损

[目的]探讨腓浅神经浅支修复桡神经缺损的临床效果。[方法]对腓浅神经浅支与桡神经形态结构进行比较，并对腓浅神经浅支移植修复桡神经缺损性损伤5例进行临床分析。[结果]腓浅神经浅支与桡神经形态结构大体一致．5例病例平均随访11(8～26)个月．按文献标准评定，优3例，良2例。[结论]腓浅神经浅支可作为修复桡神经缺损理想的供体神经。     

Facial Nerve Palsy

It is agreed that some cases of facial nerve palsy are surgical emergencies. Other cases are controversial. The best available electrodiagnostic test is 48 to 72 hours late in noting changes. An early test for axonotmesis is unavailable. Immediate consultation with a specialist qualified to deal with the problem is urged.