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Early referral of neonatal brachial plexus palsy (NBPP) patients to multidisciplinary clinics is critical for timely diagnosis, treatment, and improved functional outcomes. In Saudi Arabia, inadequate knowledge regarding NBPP is a reason for delayed referral. We aimed to evaluate the knowledge of North American healthcare providers (HCPs) regarding the diagnosis, management, and prognosis of NBPP. A 12-question survey regarding NBPP was distributed via electronic and paper formats to North American providers from various referring and treating specialties. NBPP knowledge was compared between Saudi Arabian vs. North American providers, referring vs. treating specialties, academic vs. community hospitals, and providers with self-reported confidence vs. nonconfidence in NBPP knowledge. Of the 273 surveys collected, 45% were from referring providers and 55% were from treating providers. Saudi Arabian and North American HCPs demonstrated similar NBPP knowledge except for potential etiologies for NBPP and surgery timing. In North America, referring and treating providers had similar overall knowledge of NBPP but lacked familiarity with its natural history. A knowledge gap existed between academic and community hospitals regarding timing of referral/initiation of physical/occupational therapy (PT/OT) and Horner’s syndrome. Providers with self-reported confidence in treating NBPP had greater knowledge of types of NBPP and timing for PT/OT initiation. Overall, North American providers demonstrated adequate knowledge of NBPP. However, both eastern and western physicians remain overly optimistic in believing that most infants recover spontaneously. This study revealed a unique and universal knowledge gap in NBPP diagnosis, referral, and management worldwide. Continuous efforts to increase NBPP knowledge are indicated.

Early referral of neonatal brachial plexus palsy (NBPP) patients to multidisciplinary clinics is critical for timely diagnosis, treatment, and improved functional outcomes. In Saudi Arabia, inadequate knowledge regarding NBPP is a reason for delayed referral. We aimed to evaluate the knowledge of North American healthcare providers (HCPs) regarding the diagnosis, management, and prognosis of NBPP.A 12-question survey regarding NBPP was distributed via electronic and paper formats to North American providers from various referring and treating specialties. NBPP knowledge was compared between Saudi Arabian vs. North American providers, referring vs. treating specialties, academic vs. community hospitals, and providers with self-reported confidence vs. nonconfidence in NBPP knowledge.Of the 273 surveys collected, 45% were from referring providers and 55% were from treating providers. Saudi Arabian and North American HCPs demonstrated similar NBPP knowledge except for potential etiologies for NBPP and surgery timing. In North America, referring and treating providers had similar overall knowledge of NBPP but lacked familiarity with its natural history. A knowledge gap existed between academic and community hospitals regarding timing of referral/initiation of physical/occupational therapy (PT/OT) and Horner's syndrome. Providers with self-reported confidence in treating NBPP had greater knowledge of types of NBPP and timing for PT/OT initiation.Overall, North American providers demonstrated adequate knowledge of NBPP. However, both eastern and western physicians remain overly optimistic in believing that most infants recover spontaneously. This study revealed a unique and universal knowledge gap in NBPP diagnosis, referral, and management worldwide. Continuous efforts to increase NBPP knowledge are indicated.

Background Perioperative hypothermia has been reported to increase the occurrence of cardiovascular complications. By increasing the activity of sympathetic nervous system, perioperative hypothermia also has the potential to increase cardiac injury and dysfunction associated with subarachnoid hemorrhage. Methods The Intraoperative Hypothermia for Aneurysm Surgery Trial randomized patients undergoing cerebral aneurysm surgery to intraoperative hypothermia (n = 499, 33.3 degrees +/- 0.8 degrees C) or normothermia (n = 501, 36.7 degrees +/- 0.5 degrees C). Cardiovascular events (hypotension, arrhythmias, vasopressor use, myocardial infarction, and others) were prospectively followed until 3-month follow-up and were compared in hypothermic and normothermic patients. A subset of 62 patients (hypothermia, n = 33; normothermia, n = 29) also had preoperative and postoperative (within 24 h) measurement of cardiac troponin-I and echocardiography to explore the association between perioperative hypothermia and subarachnoid hemorrhage-associated myocardial injury and left ventricular function. Results There was no difference between hypothermic and normothermic patients in the occurrence of any single cardiovascular event or in composite cardiovascular events. There was no difference in mortality (6%) between groups, and there was only a single primary cardiovascular death (normothermia). There was no difference between hypothermic and normothermic patients in postoperative versus preoperative left ventricular regional wall motion or ejection fraction. Compared with preoperative values, hypothermic patients had no postoperative increase in cardiac troponin-I (median change 0.00 microg/l), whereas normothermic patients had a small postoperative increase (median change + 0.01 microg/l, P = 0.038). Conclusion In patients undergoing cerebral aneurysm surgery, perioperative hypothermia was not associated with an increased occurrence of cardiovascular events.

Background Although hypothermia and barbiturates improve neurologic outcomes in animal temporary focal ischemia models, the clinical efficacy of these interventions during temporary occlusion of the cerebral vasculature during intracranial aneurysm surgery (temporary clipping) is not established. Methods A post hoc analysis of patients from the Intraoperative Hypothermia for Aneurysm Surgery Trial who underwent temporary clipping was performed. Univariate and multivariate logistic regression methods were used to test for associations between hypothermia, supplemental protective drug, and short- (24-h) and long-term (3-month) neurologic outcomes. An odds ratio more than 1 denotes better outcome. Results Patients undergoing temporary clipping (n = 441) were assigned to intraoperative hypothermia (33.3 degrees +/- 0.8 degrees C, n = 208) or normothermia (36.7 degrees +/- 0.5 degrees C, n = 233), with 178 patients also receiving supplemental protective drug (thiopental or etomidate) during temporary clipping. Three months after surgery, 278 patients (63%) had good outcome (Glasgow Outcome Score = 1). Neither hypothermia (P = 0.847; odds ratio = 1.043, 95% CI = 0.678-1.606) nor supplemental protective drug (P = 0.835; odds ratio = 1.048, 95% CI = 0.674-1.631) were associated with 3-month Glasgow Outcome Score. The effect of supplemental protective drug did not significantly vary with temperature. The effects of hypothermia and protective drug did not significantly vary with temporary clip duration. Similar findings were made for 24-h neurologic status and 3-month Neuropsychological Composite Score. Conclusion In the Intraoperative Hypothermia for Aneurysm Surgery Trial, neither systemic hypothermia nor supplemental protective drug affected short- or long-term neurologic outcomes of patients undergoing temporary clipping.

✓Lower-extremity pain and paresthesia have multiple origins. Early recognition of the symptoms of peripheral nerve entrapment leads to timely treatment and avoids the cost of unnecessary studies. The authors report on a case of superficial peroneal nerve syndrome resulting from nerve herniation through a fascial defect, which was responsive to surgical treatment. This 22-year-old man presented with pain and paresthesias over the lateral aspect of the right calf and the dorsum of the foot without motor weakness. Exercise led to the formation of a tender bulge approximately 12 cm above the lateral malleolus. Percussion of this site worsened his symptoms. Radiography and electromyography studies were nondiagnostic. The patient underwent surgical decompression that involved division of the fascia overlying the nerve and neurolysis of the superficial peroneal nerve. The operation resulted in symptom-free relief. Superficial peroneal nerve syndrome is an entrapment neuropathy that results from mechanical compression of the nerve at or near the point where the nerve pierces the fascia to travel within the subcutaneous tissue. Surgical decompression of the mechanical entrapment usually provides relief from pain and paresthesia.

Direct trauma, compression caused by muscle hypertrophy or other soft tissue changes, or excessive stretching of a peripheral nerve in the upper extremity may lead to uncommon-but potentially serious-complications. Clinicians are seeing more of these injuries as weight training, power lifting, bodybuilding, cross-training, and general physical conditioning with weights become more popular. Symptoms of pain, weakness, paresthesia, or palsy; physical exam findings; electromyography; and nerve conduction studies are used to make the diagnosis. Most conditions respond well to conservative measures, such as rest from the offending exercise and correction of poor technique, but surgery may be required for complete clinical resolution in severe cases.

Understanding the functional and surgical anatomy of the brachial plexus begins with in-depth knowledge of its origins. The brachial plexus is formed from portions of the spinal nerve roots at the C5 through T1 levels, known as the ventral rami. Each spinal nerve root separates into this ventral ramus and a dorsal ramus immediately after leaving its spinal foramen. The ventral rami of C5 and C6 join to form the upper trunk of the plexus. This trunk has only one branch, the suprascapular nerve, which innervates the supraspinatus and infraspinatus muscles. Just distal to this branch, the trunk divides into an anterior division to the lateral cord and a posterior division to the posterior cord.

Neonatal brachial plexus palsy (NBPP), frequently but not always associated with difficulty in the newborn’s passage down the birth canal, has likely been occurring for many centuries. The first recorded case of NBPP in the medical literature was reported in 1768 by William Smellie [1], a prominent British obstetrician. In the latter half of the 19th century, Duchene [2] and Erb [3] described and localized the lesions causing the proximal upper extremity weakness in the deltoid and biceps to the 5th and 6th cervical nerve roots. In 1885, Klumpke described a lower brachial plexus palsy with profound hand weakness and preservation of proximal strength and associated ipsilateral Horner’s syndrome, which she localized to the 8th cervical and 1st thoracic nerve roots [4]. Although the anatomy and probable etiology were thus established, treatment was largely expectant, supported by bracing and physical therapy. Kaiser Wilhelm of Germany, born during this time period (1895) with left NBPP, was treated only with extensive, even, stressful, and painful therapy to improve his function [5]. These modalities failed, leaving him with an embarrassingly shortened, weak, and withered forearm and hand. Wilhelm blamed the English doctor who attended his birth (his mother was a daughter of Queen Victoria) and consequently developed a hostility to the English, which may have played a role in the decisions leading up to World War I. The tragic consequences of this condition for this involved individual may thus be seen to have far reaching consequences. Surgical intervention was initially described by Kennedy [6] and Taylor [7] in the United States in the first decade of the 20th century. Direct suture repair was performed in these cases and in patients in several other reports. Results were initially described as favorable, but morbidity was high. In 1925, Sever reported on 1100 cases and determined that good outcomeswere not common and that a number of cases were worsened by surgery [8,9]. As a consequence, the conservative attitude regarding NBPP treatment predominated for the next several decades, awaiting and expecting some degree of recovery. In those children who did not recover well, secondary musculoskeletal procedures were occasionally used in an attempt to improve function. Brachial plexus exploration and repair were very rarely performed. Therewas, and still is, considerable controversy over the percentage of neonatal brachial plexus palsy patients who go on to a functionally acceptable spontaneous recovery. Clearly, infants with an upper plexus (Erb’s palsy) acquired perinatally who develop antigravity biceps or deltoid function by 3–4 months seem to progress to an excellent recovery. Those infants who do not meet these criteria are presumed to have a more widespread involvement of the brachial plexus and a more serious degree of injury. Their spontaneous outcome is significantly less functional. The standard regimen of physical therapy, bracing, subsequent bone

OBJECTIVE Pedicle screw fixation in the lumbar spine has become the standard of care for various causes of spinal instability. However, because of the smaller size and more complex morphology of the thoracic pedicle, screw placement in the thoracic spine can be extremely challenging. In several published series, cortical violations have been reported in up to 50% of screws placed with standard fluoroscopic techniques. The goal of this study is to evaluate the accuracy of thoracic pedicle screw placement by use of image-guided techniques. METHODS During the past 4 years, 266 image-guided thoracic pedicle screws were placed in 65 patients at the University of Michigan Medical Center. Postoperative thin-cut computed tomographic scans were obtained in 52 of these patients who were available to enroll in the study. An impartial neuroradiologist evaluated 224 screws by use of a standardized grading scheme. All levels of the thoracic spine were included in the study. RESULTS Chart review revealed no incidence of neurological, cardiovascular, or pulmonary injury. Of the 224 screws reviewed, there were 19 cortical violations (8.5%). Eleven (4.9%) were Grade II (≤2 mm), and eight (3.6%) were Grade III (>2 mm) violations. Only five screws (2.2%), however, were thought to exhibit unintentional, structurally significant violations. Statistical analysis revealed a significantly higher rate of cortical perforation in the midthoracic spine (T4–T8, 16.7%; T1–T4, 8.8%; and T9–T12, 5.6%). CONCLUSION The low rate of cortical perforations (8.5%) and structurally significant violations (2.2%) in this retrospective series compares favorably with previously published results that used anatomic landmarks and intraoperative fluoroscopy. This study provides further evidence that stereotactic placement of pedicle screws can be performed safely and effectively at all levels of the thoracic spine.

BACKGROUND Computerized tomography (CT) of metastatic adenocarcinoma to the brain usually shows low-to-moderate attenuation. However, mucinous adenomas may appear with high attenuation, mimicking hemorrhage. CASE DESCRIPTION A 68-year-old man with a history of metastatic esophageal adenocarcinoma presented to the emergency room complaining of a chronic, progressive right occipital headache. A head CT demonstrated a moderate-to-high attenuation, homogenous mass in the right cerebellar hemisphere consistent with an intracerebral hemorrhage. There was no frank calcification in the mass by CT criteria. An emergent posterior fossa craniectomy revealed nonhemorrhagic metastatic mucinous adenocarcinoma. CONCLUSION Moderate-to-high attenuation, noncalcified brain masses should raise the possibility of mucin-containing neoplasm.

✓ The pre- and postoperative lumbar spine radiographs of 119 patients who underwent decompressive lumbar laminectomy were studied to evaluate radiographic changes and to correlate them with clinical outcome. An accurate and reproducible method was used for measuring pre- and postoperative radiographs that were separated by an average interval of 4.6 years. Levels of the spine that underwent laminectomy showed greater change in spondylolisthesis, disc space angle, and disc space height than unoperated levels. Outcome correlated with radiographic changes at operated and unoperated levels.This study demonstrates that radiographic changes are greater at operated than at unoperated levels and that some postoperative symptoms do correlate with these changes. Lumbar fusion should be considered in some patients who undergo decompressive laminectomy. The efficacy of and unequivocal indications for lumbar fusion can only be determined from randomized, prospective, controlled trials, however, and these studies have not yet been undertaken.

✓ All patients who underwent decompressive lumbar laminectomy in the Washtenaw County, Michigan metropolitan area during a 7-year period were studied for the purpose of defining long-term outcome, clinical correlations, and the need for subsequent fusion. Outcome was determined by questionnaire and physical examination from a cohort of 119 patients with an average follow-up evaluation interval of 4.6 years. Patients graded their outcome as much improved (37%), somewhat improved (29%), unchanged (17%), somewhat worse (5%), and much worse (12%) compared to their condition before surgery. Poor outcome correlated with the need for additional surgery, but there were few additional significant correlations. No patient had a lumbar fusion during the study interval.The outcome after laminectomy was found to be less favorable than previously reported, based on a patient questionnaire administered to an unbiased patient population. Further randomized, controlled trials are therefore necessary to determine the efficacy of lumbar fusion as an adjunct to decompressive lumbar laminectomy.

Background Neuropathic groin pain can be a severely debilitating condition. Triple neurectomy of the ilioinguinal, iliohypogastric, and genitofemoral nerves is a viable treatment option. Objective To present our initial experience with the laparoscopic retroperitoneal approach to triple neurectomy. Methods Three patients (33 to 48 years of age) presented with chronic groin pain of 3 to 7 years' duration. The discomfort manifested in the ilioinguinal, iliohypogastric, and genitofemoral nerve distributions and severely affected their lifestyles, resulting in multiple unsuccessful medical and surgical treatments without symptomatic relief. Because the patients failed other modes of treatment, they underwent a laparoscopic retroperitoneal triple neurectomy. Results Three patients underwent a triple neurectomy from November 2006 to May 2009. All patients reported debilitating chronic groin pain and underwent prior treatments ranging from anesthetic blocks to orchiectomy without lasting relief. The first case illustrates the anatomic variation of the genitofemoral nerve and the importance of transecting both branches for adequate symptomatic relief. The remaining cases demonstrate successful transection of all 3 nerves with significant pain relief at 10 months to 3 years of follow-up. No major complications were encountered. Conclusion This technique provides several advantages in the treatment of chronic groin pain. The retroperitoneal approach provides a facile method to reach the nerves in 1 stage and provides a dissection field free of previous scars. As a laparoscopic technique, benefits include small incision sites with small scars, less postoperative pain, and shorter hospitalizations and/or same-day discharges with effective relief of groin pain.

We devised a simple method to isolate mitotically active human Schwann cells from sural nerve biopsy specimens and expand the population in culture. Nerve fascicles were treated with cholera toxin for 7 days in culture before dissociation, which increased the cell yield at least twenty-five-fold over immediated tissue dissociation. Digesting the tissue completely with enzymes in serum-containing medium resulted in the highest cell viability, and released 2 to 6 x 10(4) cells/mg of tissue. Seeding the cells on a poly-L-lysine substrate in a small volume of serum-free medium optimized the plating efficiency. Although Schwann cells comprised 90% of the initial culture population, their numbers declined over time due to a faster mitotic rate of the fibroblasts in the presence of cholera toxin alone. However, treating the cultures with a combination of cholera toxin and forskolin, which act synergistically to elevate cyclic AMP levels, inhibited fibroblast growth without causing Schwann cell toxicity. Adding glial growth factor to the adenyl cyclase activators maximized Schwann cell proliferation, and the population rapidly and selectively expanded. Therefore, it should be possible to generate large numbers of Schwann cells from diseased nerves to study defects in cell function or from normal nerves to study the effects of Schwann cell grafts on neuronal regeneration.

OBJECTIVE: We examined the incidence of perioperative fever and its relationship to outcome among patients enrolled in the Intraoperative Hypothermia for Aneurysm Surgery Trial. METHODS: One thousand patients with initial World Federation of Neurological Surgeons grades of I to III undergoing clipping of intracranial aneurysms after subarachnoid hemorrhage were randomized to intraoperative normothermia (36 degrees C-37 degrees C) or hypothermia (32.5 degrees C-33.5 degrees C). Fever (> or =38.5 degrees C) and other complications (including infections) occurring between admission and discharge (or death) were recorded. Functional and neuropsychologic outcomes were assessed 3 months postoperatively. The primary outcome variable for the trial was dichotomized Glasgow Outcome Scale (good outcome versus all others). RESULTS: Fever was reported in 41% of patients. In 97% of these, fever occurred in the postoperative period. The median time from surgery to first fever was 3 days. All measures of outcome were worse in patients who developed fever, even in those without infections or who were World Federation of Neurological Surgeons grade I. Logistic regression analyses were performed to adjust for differences in preoperative factors (e.g., age, Fisher grade, initial neurological status). This demonstrated that fever continued to be significantly associated with most outcome measures, even when infection was added to the model. An alternative stepwise model selection process including all fever-related measures from the preoperative and intraoperative period (e.g., hydrocephalus, duration of surgery, intraoperative blood loss) resulted in the loss of significance for dichotomized Glasgow Outcome Scale, but significant associations between fever and several other outcome measures remained. After adding postoperative delayed ischemic neurological deficits to the model, only worsened National Institutes of Health Stroke Scale score, Barthel Activities of Daily Living index, and discharge destination (home versus other) remained independently associated with fever. CONCLUSION: These findings suggest that fever is associated with worsened outcome in surgical subarachnoid hemorrhage patients, although, because the association between fever and the primary outcome measure for the trial is dependent on the covariates used in the analysis (particularly operative events and delayed ischemic neurological deficits), we cannot rule out the possibility that fever is a marker for other events. Only a formal trial of fever treatment or prevention can address this issue.

In the not too distant past brachial plexus injuries were considered to have a poor, almost hopeless, prognosis, and a conservative approach of waiting for any spontaneous recovery was advocated. The development of microtechniques for nerve grafting and repair combined with precise electrophysiologic testing of nerve continuity by SSEP and NAP techniques have changed this outlook completely. An aggressive approach to plexus injuries can now be advocated. This approach must be grounded in a thorough knowledge of the internal and external anatomy of the plexus and a careful analysis of each injured element. The type, location, and degree of injury to each area of the plexus are the critical factors in determining the proper course of action in these injuries. Organization of these data, derived from serial clinical and electrical examinations, provides the framework for clinical decisions in brachial plexus injuries. Classification of the many aspects of a plexus injury will simplify the decision making in what may initially seem to be a hopelessly complicated problem.

Background Anterior cervical hyperosteophytosis describes the excessive formation of osteophytes along the ventral spine. Dysphagia due to ACH is considered an uncommon entity described mainly in case reports. Symptomatic ACH has been attributed to multiple etiologies including DISH, trauma, postlaminectomy syndromes, and cervical spondylosis. We report one of the largest series of patients with ACH-induced dysphagia requiring surgery. Methods After IRB approval, a retrospective chart review was completed. From 2001 to 2006, 9 patients presented with dysphagia due to ACH requiring surgical treatment. Results Eight patients were male, and the mean age was 65.1 years. Cervical spine x-rays and CT clearly demonstrated ACH in each case. Esophagram or a video fluoroscopic swallowing study was used to verify that dysphagia was caused by osteophytic overgrowth in all instances but one. In 2 patients, a focal osteophyte had formed adjacent to a previously fused segment. Of the remaining 7 patients, osteophytic formation was attributed to cervical spondylosis in 2 patients and DISH in 5 patients. All patients underwent osteophytectomy without spinal fusion. Average follow-up was 9.8 months. Although all 9 patients experienced resolution of dysphagia, improvement was delayed in 2 patients. Conclusions Diffuse idiopathic skeletal hyperostosis and spondylosis are the most common etiologies accounting for ACH-induced dysphagia. Adjacent segment disease may also be a potential cause of symptomatic ACH and has not been previously reported. Regardless of etiology, surgical resection is highly successful if conservative measures fail.

Section I: Brachial Plexus Injury and Entrapments Section II: Upper Extremity Peripheral Nerve Injuries and Entrapments Section III: Lower Extermity Peripheral Nerve Injuries and Entrapments Section IV: Nerve Tumors, Painful Nerve Conditions, and Miscellaneous Injuries.

✓ A case of giant sacral meningioma with presacral and lumbar extension is presented. The difficulties in diagnosis and management are emphasized including the staged multidisciplinary surgical approaches and preoperative tumor embolization.

The authors discuss their recent experience with anteriorly located C1-C2 neurofibromata in five patients with cervical myelopathy and magnetic resonance scans consistent with intradural extramedullary masses in this region. Surgery was performed using a posterolateral approach with microscopic intradural exploration. Gross total intradural tumor removal was achieved in all cases. Improvement in cervical myelopathy occurred in all patients. This report concludes that C1-C2 neurofibromata located anterior to the spinal cord can be totally and safely removed using a posterolateral approach. Improvement in neurologic dysfunction accompanies posterior decompression and gross total intradural tumor removal.

Study design Review of the literature. Objectives Review the definition, etiology, incidence, and risk factors associated with as well as potential treatment options. Summary of background data The development of pathology at the mobile segment next to a lumbar or lumbosacral spinal fusion has been termed adjacent segment disease. Initially reported to occur rarely, it is now considered a potential late complication of spinal fusion that can necessitate further surgical intervention and adversely affect outcomes. Methods MEDLINE literature search. Results The most common abnormal finding at the adjacent segment is disc degeneration. Biomechanical changes consisting of increased intradiscal pressure, increased facet loading, and increased mobility occur after fusion and have been implicated in causing adjacent segment disease. Progressive spinal degeneration with age is also thought to be a major contributor. From a radiographic standpoint, reported incidence during average postoperative follow-up observation ranging from 36 to 369 months varies substantially from 5.2 to 100%. Incidence of symptomatic adjacent segment disease is lower, however, ranging from 5.2 to 18.5% during 44.8 to 164 months of follow-up observation. The rate of symptomatic adjacent segment disease is higher in patients with transpedicular instrumentation (12.2-18.5%) compared with patients fused with other forms of instrumentation or with no instrumentation (5.2-5.6%). Potential risk factors include instrumentation, fusion length, sagittal malalignment, facet injury, age, and pre-existing degenerative changes. Conclusion Biomechanical alterations likely play a primary role in causing adjacent segment disease. Radiographically apparent, asymptomatic adjacent segment disease is common but does not correlate with functional outcomes. Potentially modifiable risk factors for the development of adjacent segment disease include fusion without instrumentation, protecting the facet joint of the adjacent segment during placement of pedicle screws,fusion length, and sagittal balance. Surgical management, when indicated, consists of decompression of neural elements and extension of fusion. Outcomes after surgery, however, are modest.

Hyperdynamic therapy, consisting of hypervolemia, haemodilution, and hypertension, is an established treatment for cerebral vasospasm following subarachnoid haemorrhage. Angioplasty has emerged as an additional, effective treatment for symptomatic vasospasm. Loss of autoregulation, however, can occur despite effective angioplasty, underscoring the need for treatment with hyperdynamic therapy in combination with angioplasty. A 43-year-old woman underwent endovascular coiling of a ruptured left posterior communicating artery aneurysm. The patient went on to develop symptomatic vasospasm and was treated with hyperdynamic therapy and angioplasty. Autoregulation was assessed with xenon CT cerebral blood flow (CBF) measurement. An initial CBF study was obtained when the patient received dopamine and dobutamine infusions to maintain systolic blood pressure at 160 mmHg. The vasopressor drips were then temporarily held for twenty minutes, allowing the patient's systolic blood pressure to drop to 140 mmHg, and a repeat CBF study was obtained. Several days after angioplasty, CBF decreased significantly when the patient was taken off vasopressors, indicating impaired autoregulation. Hyperdynamic therapy was continued, and another CBF study one week later showed a return of autoregulation and normalization of CBF without induced hypertension. Autoregulation is disturbed during vasospasm. Although angioplasty can improve large artery blood flow during vasospasm, hyperdynamic therapy is also needed to maintain cerebral perfusion, particularly in the face of impaired autoregulation. Quantitative CBF measurement permits the maintenance of optimal CBF and monitoring of response to therapy.

• The piriformis muscle syndrome is a controversial "clinical" syndrome primarily characterized by signs and symptoms of sciatic nerve compression at the region of the piriformis muscle as it passes through the greater sciatic notch. The syndrome is often referred to; however, cases are rarely reported, and it is generally an uncommon diagnosis. Of those cases reported, the incidence is six times more frequent in females than in males, and is typically temporally related to minor pelvic or buttock trauma. We describe a case of a 40-year-old woman presenting with signs and symptoms suggestive of piriformis muscle syndrome following a gynecologic procedure performed in the dorsal lithotomy position. Electromyographic findings were consistent with this clinical entity. Operative exploration, however, revealed the source of neural compression to be a pseudoaneurysm of the inferior gluteal artery adjacent to the piriformis muscle. The diagnostic features of this clinical syndrome are discussed.

Rationale and Objectives. The authors evaluated a method for obtaining reproducible, reliable measurements from standard lumbar spine radiographs for determining the degree of spondylolisthesis, vertebral body height, intervertebral disk space height, disk space angle, and degree of vertebral body wedging. Materials and Methods. Four to six easily defined points were identified on each vertebral body on anteroposterior and lateral plain radiographs of the lumbosacral spine of patients. From these points, the degree of spondylolisthesis, the vertebral body height, the intervertebral disk space height, the disk space angle, and the degree of vertebral body wedging were easily calculated by using well-known geometric relationships. This method requires the use of a personal computer and a standard spreadsheet program but does not require the use of any other specialized radiographic equipment, computer hardware, or custom software. Results. Calculations of intra- and interobserver variability for the measurement of spondylolisthesis, disk space height, disk space angle, and vertebral body height measurements showed that the technique is extremely reproducible. Conclusion. This technique may prove useful in the prospective evaluation of potential candidates for lumbar spinal stenosis surgery.

✓ The University of Michigan Medical School was founded in 1847, 30 years after the university itself. The first hospital in Ann Arbor was a 20-bed unit converted from a private house, that admitted only charity patients. The second University Hospital was built in 1925. The Section of Neurosurgery was founded by Dr. Max Peet, who was followed by Drs. Kahn and Schneider as section heads.

✓ Two patients presenting with signs and symptoms suggestive of nerve root compression secondary to extradural masses were found to have ligamentum flavum hematomas. Both patients had neurological deficits preoperatively and regained normal function postoperatively. There was no significant antecedent injury in either case. The symptom course was longer than that for spontaneous epidural hematoma. In one case, there was remodeling of bone, initially suggesting either infection or tumor.

Assessment of cerebral perfusion on patients with subarachnoid haemorrhage (SAH) in the Neurologic Intensive Care Unit is difficult since nuclear medicine imaging modalities capable of measuring cerebral blood flow (CBF) are not generally available. We performed 101 quantitative (ml 100g-min) bedside CBF measurements on 40 individual patients to correlate SAH grade with CBF and to assess the effect of surgical intervention on CBF. Global CBF (G-CBF) and bihemispheric CBF (B-CBF) asymmetry were correlated with the grade of SAH pre- and post-operatively. Data analysis showed that pre-operative patients with low grade SAH (Hunt and Hess grades 0 to 2) had higher mean G-CBF values [44.2 +/- 71] than those with high grade SAH (Hunt and Hess grades 3 to 4): [mean G-CBF = 34.1 +/- 1.7]. Post-surgery there was a significant improvement in G-CBF; CBF increased [5.3 +/- 1.07] in the group of patients with low grade SAH. Patients with high grade SAH showed no significant improvement in their G-CBF during the first week post-operatively compared to pre-operative values. We conclude that portable units capable of measuring bedside CBF values are useful in monitoring CBF changes in patients with SAH. Patients with low grade SAH have G-CBF within normal limits both pre-operatively and post-operatively, with a statistically significant increase in CBF during two weeks post-operatively. Patients with high grade SAH show no significant increase in CBF one week post-operatively compared to their pre-operative measures.

A 39-year-old woman was struck by a truck traveling at high speed. Cervical computed tomography showed a dislocation between the C5 and C6 vertebrae (Panel A, sagittal reconstruction). Physical examination revealed less than antigravity strength in the bilateral deltoids with no other movement in the limbs. A C7 level with no sacral sensation was found. Gardner–Wells tongs were applied, and a closed reduction was performed within 4 hours after the initial injury. After reduction, the patient immediately regained antigravity strength in both arms and both legs. A posterior cervical fusion was performed in the operating room to stabilize normal alignment . . .

Summary Both metabolic rate and protein catabolism are known to increase following severe head trauma, but the etiology of this hypermetabolism is unknown. To further investigate the problem, we studied the metabolism of 17 patients with indirect calorimetry who had severe craniocerebral trauma only and who required ICP monitoring for management. Patients were studied daily and immediately after ICP spikes greater than 20ram Hg, prior to treatment with hyperventilation, osmotic diuretics, or barbiturates. Oxygen consumption (VO2) was correlated with ICP. Two groups of patients were identified. Group I patients were treated with hyperventilation and osmotic diuretics while Group II patients additionally received cerebral metabolic depressants. Group I had a significant correlation coefflcent between VO2 and ICP. Significant hypercatabolism early in the post trauma period was demonstrated by increased urine urea nitrogen. Our observations suggest that in patients with craniocerebral trauma, elevated ICP is associated with increased oxygen consumption, protein catabolism and systemic hypermetabolism. Cerebral metabolic depressants blunted increases in VO2 which were seen with elevated ICP.

✓ A marked increase in intracranial pressure (ICP) produces a concomitant increase in systemic blood pressure (the Cushing response). In this study a comparison is made between this response of systemic blood pressure to increased ICP and the blood pressure responses produced by ischemia, hypoxia, and hypercarbia of the primate brain. A carotid-to-carotid cross-perfusion system was used to produce a purely cerebral hypoxia and hypercarbia. Each stimulus, except hypercarbia, produced a hypertensive response that was qualitatively and quantitatively similar. These responses were characterized by a short latent period, a rapid development, and an increase in mean arterial pressure of 60% or more. The similarity of the responses suggests that these stimuli act through a final common pathway independent of the purely mechanical effects of increased ICP upon the brain.

✓ The authors' experience with the intraoperative use of real-time ultrasonography during 21 neurosurgical procedures is reported. These procedures include neoplasm surgery in 18 cases, treatment of an arteriovenous malformation in one case, and ventricular catheter placement for hydrocephalus in two cases. In each of the neoplasm cases, the tumors were imaged just as well through the intact dura as on the brain surface itself. There were no cases in which the pathology could not easily be identified. The use of portable intraoperative ultrasonography in sterile coverings has proven to be extremely useful in localizing small subcortical neoplasms, as well as locating the solid and cystic portions of deep lesions. It has assisted in guiding needles for both biopsy and aspiration. It has also accurately identified and guided Silastic catheters during their placement in the ventricular system in cases of hydrocephalus. The authors have found real-time ultrasonography to be an important new tool in the operating room and will continue to rely on its imaging ability during selected procedures in the future.

We reviewed 9 cases of sacral tumors with presacral extension. These included 2 chordomas. 1 metastatic renal cell carcinoma, 2 schwannomas (1 malignant, 1 benign), 1 neurofibroma, 1 neurofibrosarcoma, 1 aneurysmal bone cyst, and an exceedingly rare meningioma. The sex of the patients was not significant. The age of the patients at diagnosis ranged from 13 to 68 years (mean, 47 years). Initial symptoms of low back and radiating leg pain were present in all but 1 patient. The duration of symptoms prior to diagnosis ranged from 1 month to 9 years (mean, 2.6 years). A delay in diagnosis of 2 years or more occurred in 6 of the 9 patients. Progressive perineal numbness and/or sphincter dysfunction were seen in 6 patients, and a palpable rectal mass was noted in 6 of 9 patients. The efficacy of various diagnostic tests is presented, as are the surgical options—needle biopsy and anterior and posterior approaches. Despite improved radiographic imaging techniques, these unusual tumors are often diagnosed at an advanced stage, and may masquerade as discogenic radiculopathy. Late diagnosis contributes to the difficulty of surgical extirpation. Anterior and posterior surgical approaches involving general, orthopedic, and urological surgeons may be required.