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M Neuwirth

Publications and source records attributed to M Neuwirth.

At least 19 recordsLinked to original sources
PubMed2006

Monitoring of scoliosis surgery with epidurally recorded motor evoked potentials (D wave) revealed false results.

OBJECTIVE: To elucidate the mechanism behind D wave amplitude changes after surgical correction of scoliosis. METHODS: We collected D wave and muscle MEP data from 93 patients (78 female, 15 male, age range 4-19 years, mean age 15.9 years), who underwent surgical correction of scoliosis. D waves were recorded via a catheter electrode inserted epidurally through the flavectomy. Muscle MEPs from lower limb muscles were also recorded. Muscle MEPs/D wave were elicited by short trains/single transcranial electrical stimuli. SEPs were elicited through bilateral percutaneous stimulation of the tibial nerves at the ankle and an averaged response from 100 to 200 single sweeps were recorded over the scalp at Cz'/Fz. In addition, we analyzed intraoperatively obtained X-ray images of the spine in 9 patients and preoperative spinal MRI in two of those nine. RESULTS: After surgical correction of scoliosis in 25 of 93 (27%) patients, the D wave amplitude changed by more than 20% of its baseline value. A decremental change occurred in 21 (84%) and an incremental change in 4 (16%) patients. D wave decrements of more than 50% were observed in 5 patients without significant SEP changes in any of these cases. In 9 patients, intraoperatively obtained X-rays of the spine (before and after correction of spine curvature) showed no catheter displacement. Muscle MEPs did not change and postoperative sensory-motor status was normal. In 2 patients, preoperative MRI revealed displacement of the spinal cord towards the concave side of the scoliotic curvature. CONCLUSIONS: During scoliosis surgery, D wave amplitude changes should be interpreted cautiously until the definitive cause(s) of these changes are found. One possible mechanism to explain D wave changes during scoliosis correction could involve rotation of the spinal cord within the spinal canal, and the relative position of the epidural recording catheter (ERC). Rotation of the spinal cord after correction of scoliosis could introduce a new relationship between the ERC and the corticospinal tracts (CTs). Due to high incidence of false D wave amplitude changes we suggest that this methodology should not be used to assess the functional integrity of the CTs during scoliosis surgery. SIGNIFICANCE: This study provides new insight into the methodology of D wave monitoring as well as strong evidence of a high incidence of false positive results using D wave monitoring during surgical correction of scoliosis.

Action Potentials↗
PubMed2004

Bilateral epilepsy surgery in a 4-year-old child.

OBJECTIVE: Reports on bilateral epilepsy surgical interventions are anecdotal because of the possible neurological deficits caused by them. METHODS: We report on a four-year-old amaurotic child with catastrophic epilepsy due to bilateral occipital cortical dysplasia. After video-EEG monitoring and intraoperative electrocorticography he underwent a two-step bilateral occipital lobectomy. RESULTS: The first resection resulted in only temporary seizure cessation; however, he became seizure-free after the second operation (follow-up: 20 months). CONCLUSION: Patients with catastrophic epilepsy due to bilateral epileptogenic lesions but without a high risk of additional postsurgical deficit may be good candidates for epilepsy surgery.

Blindness↗
PubMed2001

[Macrocytic anemia and neurological signs due to vitamin B-12 deficiency in a breast-fed infant of a strict vegetarian mother].

Vitamin B12 deficiency is a very rare disease of infants and young children in Europe. Authors report a case of a 9.5-month-old infant who was exclusively breast-fed by his vegan mother and developed serious vitamin B12 deficiency in form of neurological regression, repetitive vomiting, drowsiness, dysphagia, obstipation, and tremor. A few days after intramuscular vitamin substitution his abnormal signs improved dramatically, hematological restitution was reached in six weeks. Authors describe the hematological and neurological signs, the diagnostic and differential-diagnostic pitfalls, therapy, prognosis, and prevention of this condition. Beside reviewing the literature they emphasize the importance of early recognition and intervention and the need of an appropriate doctor-parent cooperation in this disease.

Adult↗
PubMed2000

Injuries to the lateral femoral cutaneous nerve during spine surgery.

STUDY DESIGN: A prospective study to locate patients with injured lateral femoral cutaneous nerve after elective spine surgery. OBJECTIVES: To assess the prevalence of injury of the lateral femoral cutaneous nerve and to identify the cause of injury according to the position of the patients at surgery and the surgical approach. SUMMARY OF BACKGROUND DATA: Injuries to the lateral femoral cutaneous nerve, also known as meralgia paresthetica, may cause pain and therefore result in restriction of activity. Compression of the nerve by disc hernia, retroperitoneal tumors, and external pressure around the anterior superior iliac spine are among the more common causes. METHODS: One hundred five patients admitted for elective spine procedures were grouped according to position on the operating table and surgical approach. All patients were examined before and after surgery for signs of injury to the lateral femoral cutaneous nerve, and those found injured were followed up for 1 year after surgery. RESULTS: Injury to the lateral femoral cutaneous nerve was found in 21 (20%) patients. In 6 of them, all of whom underwent surgery on the Hall-Relton frame, the injury was bilateral. In 7 patients the injury was not associated with discomfort. In addition to injury by external pressure at the anterior superior iliac spine from the Hall-Relton frame, the nerve was also injured at the retroperitoneum by hematoma or traction and at the anterior iliac crest when bone was harvested. In 89% of the patients, the nerve completely recovered within 3 months of surgery. Two patients still had pain 1 year after surgery and hypoesthesia of the anterolateral thigh. CONCLUSION: Injuries to the lateral femoral cutaneous nerve during spine surgery are frequent, and patients should be informed of the possible risk. It usually has a benign course, but some preventive steps should be taken: keep posterior to the anterior superior iliac spine and minimize retraction when harvesting a bone graft, pad the posts of the Hall-Relton frame over the anterior superior iliac crest, and avoid traction on the psoas muscle during the retroperitoneal dissection.

Age Distribution↗
PubMed2000

Hippocampal malrotation with normal corpus callosum: a new entity?

Among 527 MRI examinations of patients with a suspicion of epilepsy in 5 years, we found 32 cases of hippocampal malrotation (HIMAL). The characteristic features are: incomplete inversion of the hippocampus with and abnormally round shape; unilateral involvement of the whole hippocampus; normal signal intensity and size; blurred internal structure; an abnormal angle of collateral sulcus; abnormal position and size of the fornix; normal size of the temporal lobe; enlargement and particular configuration of the temporal horn, typical of corpus callosum agenesis; and a normal corpus callosum. In 7 cases (22%) HIMAL occurred together with developmental disorders. It was predominantly seen in men. The clinical features were varied. Based on some MRI features, the presence of developmental disorders, the male predominance, the frequently positive family history, and a review of the literature, we think HIMAL may be the consequence of a mild hemisphere developmental disorder. It is probably not the basic cause of epilepsy in such varied clinical setting, but may be a sign of a developmental disorder and can help in selecting patients for more meticulous investigation. It also may give some new understanding of brain development.

Adult↗
PubMed2000

Instrumented posterior arthrodesis of the lumbar spine in patients with diabetes mellitus.

The existence of diabetes mellitus has been postulated to have a deleterious effect on the outcome following lumbar spine surgery. We retrospectively examined the records and radiographs of 32 diabetic patients (mean age, 60 years) who underwent posterior lumbar fusions using transpedicular instrumentation and iliac crest autograft. Ten patients were insulin-dependent and 22 required oral hypoglycemic agents for at least 1 year prior to surgery. The minimum follow-up time was 2 years after surgery (mean, 2.5 years). Surgical indications included herniated lumbar disk, lumbar spinal stenosis, thoracolumbar trauma, and lumbar pseudarthrosis. Clinical results were evaluated by chart review and/or interview by using Odom's criteria. At follow-up, 75% of patients were graded as excellent or good, and 25% as fair or poor. Twenty-five of 32 patients (78%) had improvement of back pain. Twenty of 27 (74%) patients had improvement of leg pain. Eight of 15 (53%) patients had improvement in motor strength, and 6 of 11 (54%) had improvement in light-touch sensation. Insulin dependence and the presence of polyneuropathy were associated with a poorer outcome. The average time to radiographic fusion was 5 months. Twenty-nine of 32 patients (91%) developed solid fusion by strict radiographic criteria. The three patients with a pseudarthrosis had persistent back pain and a poor result. Ten of 32 (31%) of the patients experienced perioperative complications, including prolonged wound drainage (n = 5), deep wound infection (n = 1), superficial wound infection (n = 1), atrial fibrillation (n = 1), ruptured cerebral aneurysm (n = 1), and ulnar nerve neuropathy (n = 1). We conclude that posterolateral lumbar spinal fusion with internal fixation in diabetic patients yields clinical results comparable to those of nondiabetic patients, with similar risks of perioperative complications.

Bone Screws↗
PubMed1998

Anal duct/gland cyst: report of a case and review of the literature.

PURPOSE: The purpose of this communication is to report a case of anal duct/gland cyst and review cases of perianal and presacrococcygeal mucus-secreting cysts reported in the literature with emphasis on their histopathologic features. METHOD: Our patient presented with coccydynia. An extraluminal retrorectal tumor was felt on rectal examination. A computerized tomographic scan demonstrated a presacrococcygeal mass closely related to the anorectal junction. The tumor and the coccyx were excised using a posterior approach. Cases of perianal and presacrococcygeal mucus-secreting cysts reported in the literature were reviewed. RESULTS: In our case, the tumor proved to be an anal duct/gland cyst. Some of the reported cases of presacrococcygeal glandular cysts had histopathologic features suggestive of anal duct/gland origin. CONCLUSION: Diagnosis of anal duct/gland cyst is based on routine histologic features, histochemical characteristics of mucus, and/or the presence of a communication with an anal duct or crypt. Based on these criteria, some of the reported cases of mucus-secreting cysts occurring around the anorectum may prove to be anal duct/gland in origin.

Aged↗
PubMed1994

Thrombotic occlusion of the left common iliac artery after an anterior retroperitoneal approach to the lumbar spine.

Thrombotic occlusion of the left common iliac artery occurred in a 59-year-old man after an anterior and posterior spinal fusion. Preoperatively, the patient was known to have peripheral vascular disease. Symptoms of an L4-5 radiculopathy were noted postoperatively. After an iliac-iliac bypass, the symptoms completely resolved. Retraction of the vessels during the anterior retroperitoneal approach was the presumed cause. To the authors' knowledge, this is the first report of a thrombotic occlusion developing in a patient after an anterior retroperitoneal approach to the lumbar spine. It is their hope that through an increased awareness similar complication will be prevented.

Arteriosclerosis↗
PubMed1993

Translaminar facet screw fixation in lumbar spine fusion.

This study evaluates the clinical result and fusion rate in 61 patients who underwent posterolateral spine fusions augmented with translaminar facet screw fixation at an average of 24 months after surgery. Sixty patients (98.4%) were judged to have a solid fusion by radiographic examination at an average of 5 months. Fifty-seven patients (93.4%) rated the result of their surgery as good to excellent; four patients (6.6%) rated their result as unsatisfactory. There were no patients with nerve root injury or other neurologic deficit. The 98.4% fusion rate compares favorably with other methods. The results of this study support the continued use of translaminar facet screw fixation to augment posterolateral fusion in the lumbar spine.

Adolescent↗
PubMed1988

Cyclic loading of segmental spinal instrumentation.

The ultimate clinical effect of SSI stability and rigidity is not known, but three SSI systems exhibited different displacements during cyclic loading in an in-vitro model. Although no failure of the SSI system occurred at 50,000 cycles, the possibility of fatigue failure cannot be excluded, particularly in view of the minor damage and significant displacements observed at some of the connecting interfaces. For that reason, static testing of SSI should be augmented by cyclic testing whenever possible, as this can elucidate other failure mechanisms, particularly since the expected clinical loading of these systems is greater than 10(6) cycles.

Animals↗
PubMed1986

Symptomatic vertebral hemangiomas: a report of four cases.

Neural compression complicating vertebral hemangioma is associated with: compression fracture, hematoma, epidural extension of tumor, and/or bony expansion or "ballooning." Four cases of symptomatic vertebral hemangioma are presented. Discussion includes imaging modalities, preoperative embolization, and surgical approach.

Adult↗
PubMed1983

Scoliosis and growth. An analysis of the literature.

A review of the literature discloses the buckling phenomenon as responsible for the initiation of lateral deformation and the progression of small curves in idiopathic scoliosis. From the point of view of parsimony, buckling explains how ligamentous laxity, increased interdiscal flexibility, muscular asymmetries, neurologic lesions, morphologic, anthropometric, and sexual differences would contribute to development of the deformity. Thus, a buckling theory seems to embody the fragmented character of present information about the etiology of idiopathic scoliosis.

Adolescent↗
PubMed1982

Three-dimensional lordosimeter. A device for the nonradiographic assessment of spinal configuration.

A technique is presented for the nonradiographic assessment of spinal configuration. Its use in the assessment of scoliotic curvatures is discussed in the light of existing radiographic and nonradiographic techniques. The reproducibility of point-encoding measurements relative to a fixed standard is shown to be 98.8 percent. The correlation of pointencoded spinal angles with similar data taken from x-rays is significant at p less than 0.0005. The average standard deviation in the measurement of spinal angles of 10 successive trials on five test subjects is 3.55 degrees +/- 1.95 degrees.

Humans↗
PubMed1981

Ultrastructure of granules and immunocytochemical localization of luciferase in photocytes of fireflies.

Photocyte granules are round to oval, 1-2 micron, contain a peripheral dense area and are of three structural types. Type one granules consist of an amorphous matrix, a bundle of 2-12 microtubules and a flask-shaped vacuole. The type two granule is characterized by a large crystal or several smaller crystals embedded in an amorphous matrix with microtubules lined up along the face of the crystal. The type three granule is filled with a large number of thick-walled tubules (40-50 nm o.d.), usually found in bundles of two to four and a few microtubules. Luciferase has been shown to be localized in these photocyte granules by the immunoferritin technique. Ferritin is not localized over microtubules or flask-shaped vacuoles in type one granules but is randomly distributed over the matrix. In type two granules, ferritin is more densely distributed over the crystals and in type three granules over filamentous structures. There is no ferritin over the microtubules. Other parts of photocytes and of light organs are negative for luciferase. Buffer and anticalliphorin incubated sections showed no ferritin in granules.

Animals↗