Belachew Arasho

Management of the trigeminocardiac reflex: facts and own experience.

The trigeminocardiac reflex (TCR) is defined as the sudden onset of parasympathetic dysrhythmia, sympathetic hypotension, apnea, or gastric hyper-motility during stimulation of any of the sensory branches of the trigeminal nerve. The proposed mechanism for the development of TCR is--the sensory nerve endings of the trigeminal nerve send neuronal signals via the Gasserian ganglion to the sensory nucleus of the trigeminal nerve, forming the afferent pathway of the reflex arc. It has been demonstrated that the TCR may occur with mechanical stimulation of all the branches of the trigeminal nerve anywhere along its course (central or peripheral). The reaction subsides with cessation of the stimulus. But, some patients may develop severe bradycardia, asystole, and arterial hypotension which require intervention. The risk factors already known to increase the incidence of TCR include: Hypercapnia; hypoxemia; light general anesthesia; age (more pronounced in children); the nature of the provoking stimulus (stimulus strength and duration); and drugs: Potent narcotic agents (sufentanil and alfentanil); beta-blockers; and calcium channel blockers. Because of the lack of full understanding of the TCR physiology, the current treatment options for patients with TCR include: (i) risk factor identification and modification; (ii) prophylactic measures; and (iii) administration of vagolytic agents or sympathomimetics.

Trigeminocardiac reflex: the current clinical and physiological knowledge.

The trigeminocardiac reflex (TCR) is defined as the sudden onset of parasympathetic dysrhythmia, sympathetic hypotension, apnea, or gastric hypermotility during stimulation of any of the sensory branches of the trigeminal nerve. Clinically, the TCR has been reported in all the surgical procedures in which a structure innervated by the trigeminal nerve is involved. Although, there is an abundant literature with reports of incidences and risk factors of the TCR; the physiological significance and function of this brainstem reflex has not yet been fully elucidated. In addition, there are complexities within the TCR that requires examination and clarification. There is also a growing need to discuss its cellular mechanism and functional consequences. Therefore, the current review provides an updated examination of the TCR with a particular focus on the mechanisms and diverse nature of the TCR.

A new predisposing factor for trigemino-cardiac reflex during subdural empyema drainage: a case report.

IntroductionThe trigemino-cardiac reflex is defined as the sudden onset of parasympathetic dysrhythmia, sympathetic hypotension, apnea, or gastric hypermotility during stimulation of any of the sensory branches of the trigeminal nerve. Clinically, trigemino-cardiac reflex has been reported to occur during neurosurgical skull-base surgery. Apart from the few clinical reports, the physiological function of this brainstem reflex has not yet been fully explored. Little is known regarding any predisposing factors related to the intraoperative occurrence of this reflex.Case presentationWe report the case of a 70-year-old Caucasian man who demonstrated a clearly expressed form of trigemino-cardiac reflex with severe bradycardia requiring intervention that was recorded during surgical removal of a large subdural empyema.ConclusionTo the best of our knowledge, this is the first report of an intracranial infection leading to perioperative trigemino-cardiac reflex. We therefore add a new predisposing factor for trigemino-cardiac reflex to the existing literature. Possible mechanisms are discussed in the light of the relevant literature.

The trigemino-cardiac reflex in adults: own experience

The trigemino-cardiac reflex The trigemino-cardiac reflex (TCR) has previously been described in the literature as a reflexive response composed of bradycardia, hypotension and gastric hypermotility seen upon mechanical stimulation anywhere in the distribution of the trigeminal nerve [1–5]. Based on the initial rabbit neurostimulation experiments of Kumada et al. in 1977 [6], TCR was first observed by Schaller et al. in 1999 during neurosurgical operations [5]. By systematic observation, the incidence of the TCR during neurosurgical procedures around the trigeminal nerve was shown to be approximately 10–18%, independently of the surgeon who operated or the approach that was used [3,7–12]. In their key works, Schaller et al. first defined TCR in detail, and their observations are at present generally accepted [3,5,13–15].

Trigemino-cardiac reflex during chronic subdural haematoma removal: report of chemical initiation of dural sensitization.

The paper presents a new risk factor for the trigemino-cardiac reflex and goes deep into the reflexs physiology.

Ischemic tolerance in stroke treatment

Although outcome after stroke treatment has significantly improved over the last 30 years, there has been no revolutionary breakthrough. Among different combined approaches, systemic thrombolysis in combination with neuroprotection became a favorite research target. Recent studies suggest that transient ischemic attacks may represent a clinical model of such ischemic tolerance; thus, a new focus on this research has emerged. In this review, we show the parallels between ischemia and neuroprotection and discuss the potential therapeutic options that may be opened by this new molecular knowledge.

Wallis interspinous implantation to treat degenerative spinal disease: description of the method and case series

The Wallis interspinous implant is most commonly used in the treatment of intervertebral disc herniation and for tears in the outer layer of the disc. The dynamic vertebral fixation concept was first initiated in 1984 with the goal of imitating the physiologic spinal kinetic. A total of 15 years later, a second generation of implant has been developed, termed the ‘Wallis interspinous Implant’, which aims to preserve the mobility of the operated spinal segment. To underline our own experience, a retrospective review of 15 patients that were treated with ‘Wallis implantation’ at our institution between January 2006 and March 2008. Our main inclusion criterion for Wallis implantation was low back pain because of degenerative lumbar spinal stenosis associated with segmental instability along with Modic changes 0–1 and with UCLA arthritic grade II in the adjacent two segments cephalad to implantation. The outcome was analyzed according to clinical and radiological parameters. One (n = 9), two (n = 4) and three levels (n = 2) were operated on using Wallis implantation, ranging from L2–L3 to L5–S1. We used implants of 8–14 mm in size. There was a reduction in low back pain (73 vs 43%) and gait disturbances (73 vs 14%) at the 3-month follow-up compared with preoperative values. In line with these results, the modified Japan Orthopedic Assocation Score (mJAOS) was increased from 12 preoperatively to 18 at 3 months and 20 at 12 months postoperatively. A reduction in low back pain could only be demonstrated for implants that were 10 mm in size or greater at 3 months and 12–15 months postoperatively. An improvement was seen in Modic grades after the operations as compared with those observed at preoperative MRI. The outcome in our patients was rated as good or excellent according to Odom’s criteria in all cases, independent of the levels that were used. Wallis implantation is therefore a safe procedure with a good to excellent outcome in the short- and mid-term follow-up and can lead to disc rehydration, as confirmed by postoperative MRI. Principal postoperative (clinical) success is based on the correct implant size.

Transsphenoidal/Transcranial Surgery of Pituitary Adenomas: Prognosis-Related Occurence for the Trigemino-Cardiac Reflex

This chapter summarizes the well-known trigemino-cardiac reflex (TCR) that was first introduced into skull base surgery by the senior author. We present here the prognostic factors of this brainstem reflex by the example of the transcranial/transsphenoidal operations for pituitary adenomas. A retrospective study of all patients operated on a pituitary adenoma were evaluated between 2000 and 2006. Building two subgroups with and without intraoperative occurrence of the TCR, there was seen no difference in the patients characteristics between these two subgroups. But we found a significant difference for loop diuretics and potassium-sparing diuretic favouring the TCR subgroup. In addition, there is also a significant difference for psychostimulans and morphine analogues. From the present point of knowledge it is not clear whether or not the risk profile is at least dependent of the peripheral or central stimulation of the nerve and may therefore be changed for different skull base operations. So that the present risk factor are only valuable in operations for pituitary adenomas. The knowledge of the TCR is nowadays a MUST for every skull base surgeon and also for every physicians involved in the treatment of patients with skull base pathologies.

Molecular imaging of potential bone metastasis from differentiated thyroid cancer: a case report

IntroductionMolecular imaging of the spine is a rarely used diagnostic method for which only a few case reports exist in the literature. Here, to the best of our knowledge we present the first case of a combination of molecular imaging by single photon emission computer tomography and positron emission tomography used in post-operative spinal diagnostic assessment.Case presentationWe present the case of a 50-year-old Caucasian woman experiencing progressive spinal cord compression caused by a vertebral metastasis of a less well differentiated thyroid cancer. Following tumor resection and vertebral stabilization, total thyroidectomy was performed revealing follicular thyroid carcinoma pT2 pNxM1 (lung, bone). During follow-up our patient underwent five radioiodine therapy procedures (5.3 to 5.7 GBq each) over a two-year period. Post-therapeutic I-131 scans showed decreasing uptake in multiple Pulmonary metastases. However, following an initial decrease, stimulated thyroglobulin remained at pathologically increased levels, indicating further neoplastic activity. F18 Fludeoxyglucose positron emission tomography, which was performed in parallel, showed remaining hypermetabolism in the lungs but no hypermetabolism of the spinal lesions correlating with the stable neurological examinations. While on single photon emission computer tomography images Pulmonary hyperfixation of I-131 disappeared (most likely indicating dedifferentiation), there was persistent spinal hyperfixation at the operated level and even higher fixation at the spinal process of L3. Based on the negative results of the spinal F18 fludeoxyglucose positron emission tomography, a decision was made not to operate again on the spine since our patient was completely asymptomatic and the neurological risk seemed to be too high. During further follow-up our patient remained neurologically stable.ConclusionsMolecular imaging by F18 fludeoxyglucose positron emission tomography helps to exclude metabolically active spinal metastases and to spare further risky surgery.

Distal symmetric polyneuropathy and toxic neuropathy in HIV patients

Several neurological diseases have been associated with Human Immunodeficiency Virus (HIV) infection. These could either be a direct result of the virus (HIV associated dementia and HIV related painful distal polyneuropathy) or of opportunistic infections or neoplasm. HIV related neuropathy is one of the most common neurological complications of HIV infection. There are various forms of neuropathy in HIV patients which can be broadly classified into: (i) distal symmetric polyneuropathy (DSP), (ii) mononeuropathy multiplex (iii) acute and chronic inflammatory demyelinating polyneuropathies (iv) lumbosacral polyradiculopathy (v) diffuse infiltrative lymphocytosis syndrome (DILS) (vi) autonomic neuropathy, mononeuropathies (vii) herpes zoster radiculitis and (viii) sensory ganglioneuritis. DSP represents the most common form of neuropathy seen in patients with HIV and affects about 30% of patients. Pathologic findings of DSP occur in almost all patients with advanced immunodeficiency at autopsy. However, with HAART, the incidence of DSP appears to be decreasing compared to the pre-HAART era. Some studies show a substantial increase in the prevalence of DSP and this may be related to an increased longevity of patients and neurotoxic effects of some anti-retroviral drugs. Anti-retroviral toxic neuropathy (ATN) occurs with the di-deoxnucleoside group of drugs (DDI, stavudine, and DDC) and is thought to be the direct neurotoxic effect of the drugs. The two forms are clinically indistinguishable and present in a length dependent axonal polyneuropathy. DSP and ATN cause devastating complications and are related to poor treatment compliance. The objective of this review is to update current knowledge in the two main forms of neuropathy in HIV infection. We believe that physicians practicing in highly HIV prevalent areas (Sub-Saharan Africa and other developing countries) need to look for these complications in their HIV patients and manage them accordingly.