Distinctive Characteristics of Thoracolumbar Junction Region Stenosis

STUDY DESIGN

Retrospective case series and systemic literature meta-analysis.

BACKGROUND

Thoracolumbar junction region stenosis produces spinal cord compression just above the conus and may manifest with symptoms that are not typical of either thoracic myelopathy or neurogenic claudication from lumbar stenosis.

OBJECTIVE

As few studies describe its specific pattern of presenting symptoms and neurological deficits, this investigation was designed to improve understanding of this pathology.

METHODS

A retrospective review assessed surgically treated cases of T10-L1 degenerative stenosis. Clinical outcomes were evaluated with the thoracic Japanese Orthopedic Association score. In addition, a systematic review and meta-analysis was performed in accordance with guidelines provided by the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA).

RESULTS

Of 1069 patients undergoing laminectomy at 1477 levels, 31 patients (16M/15F) were treated at T10-L1 a mean age 64.4 (SD=11.8). Patients complained of lower extremity numbness in 29/31 (94%), urinary dysfunction 11/31 (35%), and back pain 11/31 (35%). All complained about gait difficulty and objective motor deficits were detected in 24 of 31 (77%). Weakness was most often seen in foot dorsiflexion 22/31 (71%). Deep tendon reflexes were increased in 10 (32%), decreased in 11 (35%), and normal 10 (32%); the Babinski sign was present 8/31 (26%). Mean thoracic Japanese Orthopedic Association scores improved from 6.4 (SD=1.8) to 8.4 (SD=1.8) ( P <0.00001). Gait subjectively improved in 27/31 (87%) numbness improved in 26/30 (87%); but urinary function improved in only 4/11 (45%).

CONCLUSIONS

Thoracolumbar junction stenosis produces distinctive neurological findings characterized by lower extremity numbness, weakness particularly in foot dorsiflexion, urinary dysfunction, and inconsistent reflex changes, a neurological pattern stemming from epiconus level compression and the myelomeres for the L5 roots. Surgery results in significant clinical improvement, with numbness and gait improving more than urinary dysfunction. Many patients with thoracolumbar junction stenosis are initially misdiagnosed as being symptomatic from lumbar stenosis, thus delaying definitive surgery.

Spontaneous Hemorrhage followed by paraparesis in a patient with a Spinal Meningioma

BACKGROUND

Although rare, spinal meningiomas may cause motor and sensory deficits or difficulty with bladder or bowel function due to spinal cord compression. While hemorrhage of intracranial meningiomas is well documented, there are very few cases of hemorrhage or hematoma associated with spinal meningiomas in the literature. Spinal meningiomas have been reported to be associated with subdural, epidural, intratumoral, and subarachnoid hemorrhage and usually in the setting of inciting event such as lumbar puncture or anti-coagulation therapy.

CASE DESCRIPTION

A 68-year old women presented to the emergency room with acute onset of paraparesis in the lower extremities. MRI findings were inconclusive for cause but showed cord compression. Intra-operative findings demonstrated an intratumoral hemorrhage and pathology was consistent with meningioma.

CONCLUSIONS

This is the first report found in the English literature of a patient who first develops symptoms from a spinal meningioma with spontaneous intratumoral hemorrhage presenting with acute paraparesis. MRI findings in retrospect match surgical intra-operative findings. Prompt surgical intervention can result in complete resolution of neurological deficits.

PTEN inhibits adrenomedullin expression and function in brain tumor cells

Adrenomedullin is a vasoactive peptide that is upregulated in higher-grade gliomas and promotes tumor cell proliferation. Since reduced activity of the anti-oncogene PTEN seems to also correlate with higher tumor grade, this suggests an inverse association between PTEN activity and adrenomedullin expression. PC12 pheochromocytoma and human U251 glioma cell lines were stably transfected with human PTEN or control plasmid. Adrenomedullin expression was analyzed using quantitative PCR and Western blotting. A cell proliferation assay was used to assess adrenomedullin effects on U251 cells overexpressing PTEN. PC12 and U251 cells overexpressing PTEN had 17- and 8-fold decreases in adrenomedullin mRNA levels, respectively, compared to control cells. Cellular and secreted adrenomedullin peptide was similarly reduced. Addition of adrenomedullin to medium of controlled cells induced proliferation, as described previously, but U251 cells overexpressing PTEN did not respond to exogenous adrenomedullin. Further exploration revealed that PTEN also inhibits expression of the gliomas receptor for adrenomedullin, which accounts for this effect. These data were all replicated with an inducible PTEN construct confirming that these effects are not exclusively secondary to chronic overexpression. Given the profound effects of adrenomedullin on tumor cells, this is a novel and previously unidentified mechanism by which alterations in PTEN levels or function may influence tumor growth.

Long-term hearing preservation after surgery for vestibular schwannoma

Object. Vestibular schwannomas (VSs) are now amenable to resection with excellent hearing preservation rates. It remains unclear whether immediately postoperative hearing is a durable result and will not diminish over time. The aim of this study was to determine the rate of long-term preservation of functional hearing following surgery for a VS and to examine factors influencing hearing preservation.

Methods. All patients eligible for hearing preservation (Gardner—Robertson Class I or II) who had undergone resection of a VS by a single surgeon were reviewed retrospectively. Follow-up audiograms and magnetic resonance images were obtained.

Of 142 patients deemed eligible for hearing preservation surgery, 38 had immediate postoperative hearing confirmed by an audiogram. In these patients with preserved hearing, the audiographic results demonstrated functional hearing in 30 (85.7%) of 35 patients who underwent repeated testing at a mean follow-up time of 7 years. Delayed hearing loss occurred in five (14.3%) of the 35 patients and did not correlate significantly with the size of the tumor. Hearing improved one Gardner—Robertson class postoperatively in three (7.9%) of the 38 patients.

Conclusions. Long-term functional hearing was maintained in 85.7% of patients when it was preserved immediately postoperatively and the result was independent of tumor size. The results of this study emphasize that long-term preservation of functional hearing is a realistic goal following VS surgery and should be attempted in all patients in whom preoperative hearing is determined to be Gardner—Robertson Class I or II.

Self-assessed quality of life after acoustic neuroma surgery

Object. The aim of this study was to determine if factors such as postoperative hearing, facial function, headaches, or other factors have an impact on self-assessed quality of life (QOL) after acoustic neuroma surgery.

Methods. The SF-36 and seven additional questions on the impact of surgery on the QOL were sent to 135 consecutive patients who had undergone acoustic neuroma surgery. The Spearman rho correlations were calculated for each of the eight categories of the SF-36 (general health, physical functioning, physical role limitations, emotional role limitations, mental health, energy/vitality, pain, social functioning). The results were correlated with patients' sex, age, persistent headache, years since surgery, postoperative hearing level, and facial function.

The response rate was 74.8%. The transformed scores of the eight categories of the SF-36 were lower than age-matched healthy controls in approximately half of the categories. The strongest trend toward lower scores with statistical significance in two categories was persistent headaches. Some categories demonstrated trends toward lower scores with females or age older than 55 years. Postoperative hearing and facial functioning, and time since surgery showed no statistically significant impact on QOL measured by the SF-36. Responses to the additional questions indicate that hearing, facial function, and headache influenced people's feelings about surgery and had an impact on their return to work.

Conclusions. The QOL scores are not consistently lower than population normative values compared with different normative studies. The strongest correlation was between the presence of persistent headache and QOL. Other correlations were not consistent in all categories, and few were statistically significant. These trends in some categories do not explain the difference seen between patients after acoustic neuroma surgery in this study and normal populations in other studies.

Future and current surgical therapies in Parkinson's disease

PURPOSE OF REVIEW

The mainstay of treatment for Parkinson's disease remains medical therapy. With improved surgical precision and decreased morbidity, stereotactic lesioning and deep brain stimulation have become more popular. New therapies currently in clinical trials include gene therapy and direct drug delivery to the brain. The present review discusses surgical therapies for the treatment of Parkinson's disease and the status of experimental strategies currently in preclinical and clinical testing.

RECENT FINDINGS

Both stereotactic ablation and deep brain stimulation of the thalamus, globus pallidus interna, and subthalamic nucleus are discussed and compared in the current literature. New therapies such as drug infusions into the brain, gene therapy, and neural transplantation are in clinical trials and have been tested extensively in animals. Safety and efficacy of such therapies are discussed in recent literature.

SUMMARY

Although medication remains the first and main line of treatment and the mainstay for Parkinson's disease, advances in techniques and safety of operations have made surgical interventions more popular. Thalamic surgery remains helpful only in a limited subset of patients with predominent tremor that is unresponsive to medication. Bilateral subthalamic nucleus DBS holds the most promising results for patients with tremor, severe motor fluctuations and dyskinesias from L-dopa, with the best improvements seen in daily activities and quality of life. Newer therapies currently in clinical trial include gene therapy to replace lost gamma-aminobutyric acid inputs to the subthalamic nucleus and globus pallidus interna/substantia nigra pars reticulata, and infusion of recombinant glial derived neurotrophic factor to support at-risk nigrostriatal neurons. Further developments in these areas, along with evolution in stem cell science that hopefully will permit replacement of lost neurons, may alter the nature of surgical practice in Parkinson's disease patients in the not too distant future.

Bilateral detection thresholds in dextrals and sinistrals reflect the more sensitive side of the nose, which is not lateralized

Several fundamental questions remain enigmatic concerning human olfactory sensitivity, including (i) whether detection threshold differences exist between the two sides of the nose (and, if so, whether such differences are influenced by handedness) and (ii) whether bilateral (i.e. binasal) stimulation leads to lower thresholds than unilateral stimulation (and, if so, whether the degree of facilitation is inversely related to general olfactory ability). In this study, and well-validated single staircase procedure was used to establish bilateral and unilateral detection thresholds for the cranial nerve I stimulant phenyl ethyl alcohol in 130 right- and 33 left-handed subjects. No differences in sensitivity between the left and right sides of the nose were observed in either group. Bilateral thresholds were lower, on average, than unilateral thresholds when the latter were categorized in terms of left and right nares. However, the bilateral thresholds did not differ significantly from those of the side of the nose with the lower threshold. Overall smell ability, as measured by the University of Pennsylvania Smell Identification Test, did not interact with any of the test measures. These data imply that (i) the left and right sides of the nose do not systematically differ in detection threshold sensitivity for either dextrals or sinistrals and (ii) if central integration of left:right olfactory threshold sensitivity occurs, its effects do not exceed the function of the better side of the nose.