Causes of facial nerve paresis after translabyrinthine surgery for acoustic neuroma.

Forty-six consecutive video-recorded translabyrinthine operations at Gentofte Hospital, for tumors of 5 to 25 mm, were investigated for possible damage to the facial nerve from cauterization, suction, stretching, pushing, and other instrumental trauma at the following regions: fundus, internal meatus, porus, cerebellopontine angle, and brain stem. House-Brackmann grading of the postoperative facial nerve function was determined from the patient records for the 1st, 3rd, and 10th days and 3 months and 6 months postoperatively, as well as the final status. Suction on the nerve seems to be the most important factor for perioperative facial nerve damage. The most common site of damage was the porus region. This investigation shows thermic drilling lesions to be very relevant. There was no correlation between the degree and character of damage and the postoperative facial nerve function. In eight patients we cannot explain the postoperative facial palsy.     

Serum acetylcholinesterase and prognosis of acute organophosphate poisoning

OBJECTIVE: The aim of this study is to investigate the prognostic value of serum acetylcholinesterase levels and their relationship with neurological syndromes (Type 1 syndrome, intermediate syndrome, and delayed polyneuropathy) in acute organophosphate poisoning. MATERIALS AND METHODS: Thirty-two consecutive patients with acute organophosphate poisoning admitted to the Ondokuz Mayis University Emergency Department from June 1999 to January 2001 were evaluated. Patients were assessed according to admission time, symptoms, and results of clinical exams and their serum acetylcholinesterase levels were determined on days 1, 2, 3, 7, and the last day. RESULTS: There was no significant difference between the first-day serum acetylcholinesterase of the patients with severe poisoning (n = 22, 68.75%) and of the patients with mild poisoning (n = 10, 31.25%; NS). There was no discernible difference between the serum acetylcholinesterase obtained on days 1 and 3 after poisoning from the patients with intermediate syndrome (n = 5, 15.6%; means: 0.90 +/- 0.65 vs. 0.88 +/- 0.53, 19.35 vs. 18.92%; NS, sensitivity = 80%; specificity = 87.5%). There was a significant difference between the serum acetylcholinesterase obtained on days 1 and 3 from the patients with nonintermediate syndrome (n = 24, 75%; means: 1.05 +/- 0.24 vs. 1.68 +/- 0.29, 22.58 vs. 36.12%; p < 0.001). There was no discernible significant difference in serum acetylcholinesterase between the patients with organophosphorus-induced delayed polyneuropathy (n = 7, 21.8%) and nonorganophosphorus-induced delayed polyneuropathy. In the patients who died (n = 5, 15.6%), serum acetylcholinesterase showed no discernible increase day 1-the last day (means: 0.50 +/- 0.25 vs. 0.46 +/- 0.26, 10.75 vs. 9.89%; NS). There was a significant difference between the serum acetylcholinesterase levels obtained on days 1 and the last day from the patients who survived (n = 27, 84.3%; means: 1.14 +/- 0.25 vs. 2.32 +/- 0.26, 24.51 vs. 49.89%; p < 0.001). CONCLUSION: In the acute phase of organophosphate poisoning, low serum acetylcholinesterase (> 50% of minimum normal value) supports the diagnosis of organophosphate poisoning but it does not show a significant relationship to the severity of poisoning (NS). The serum acetylcholinesterase activity may be a useful parameter in following the acute prognosis of organophosphate poisoning.     

Variations in the anatomy of the inferior alveolar nerve

Variations in the anatomy of the inferior alveolar nerve were seen in 2 of the 20 dissections of the infratemporal fossa in 10 cadavers. A connecting nerve branch that originated from the auriculotemporal nerve joined the inferior alveolar nerve on both sides. The second part of the maxillary artery passed between the mandibular nerve, the root of the inferior alveolar nerve, and the connecting nerve branch which formed a loop. The maxillary artery seemed to be entrapped. Neurovascular entrapment can cause pain and numbness. Anatomical variations in this region should be kept in mind, particularly in cases of failed treatment of trigeminal neuralgia.     

Intrathecal gadolinium (gadopentetate dimeglumine) enhanced magnetic resonance myelography and cisternography: results of a multicenter study

RATIONALE AND OBJECTIVES: This cooperative multicenter human study was designed to evaluate the safety, magnetic resonance (MR) imaging characteristics, and clinical response to a single gadolinium contrast agent: gadopentetate dimeglumine. MATERIAL AND METHODS: Ninety-five patients (age range: 1 month to 78 years; sex: 50 males, 45 females) were included in this prospective study. The patients presented clinically with a variety of cranial or spinal signs and symptoms for which an intrathecal contrast myelogram or cisternogram was requested by clinical staff. Via lumbar puncture (20-25 g needle), 3 to 5 mL/ml of cerebrospinal fluid were withdrawn and mixed with a single volume of 0.5 (n = 63), 0.7 (n = 13), 0.8 (n = 12), or 1.0 (n = 7) cc/mL of gadopentetate dimeglumine (Magnevist; Schering, Berlin, Germany). This was then injected into the subarachnoid space, and the needle was removed. Immediate and delayed (up to 96 hours) T1- and T2-weighted MR imaging was performed on super conductive, high-field (1.0-1.5 tesla) imaging units in two or three planes. All patients were hospitalized for an observation period of 24 hours following the procedure, and follow-up neurologic examinations were performed serially for 6 to 12 months afterward. RESULTS: No patient manifested gross behavioral changes, neurologic alterations, or seizure activity at any time following the procedure. Nineteen patients (20%) experienced postural postlumbar puncture headache, six patients had nausea (6%), and two patients had episodes of vomiting (2%), all which resolved within the first 24 hours of the lumbar puncture with conservative bed rest. CONCLUSION: This cooperative study demonstrates the general safety and feasibility of low dose (0.5-1.0 mL/ml) intrathecal gadopentetate dimeglumine administration. The potential useful clinical applications include the evaluation of obstructions and communications of the various subarachnoid spaces, spontaneous or traumatic/postsurgical craniospinal cerebrospinal fluid leaks, and subarachnoid space CSF flow and parenchymal CNS interstitial diffusion dynamics. This worldwide cooperative study seeks to progressively perform human studies for further definitive evaluation of the practical clinical applications, of the relationship of this technique to other imaging studies and modalities, and the long-term safety of the procedure in a larger number of subjects.