Late radiographic findings after anterior cervical fusion for spondylotic myeloradiculopathy

A retrospective study was performed to evaluate the radiographic changes that occurred at spinal levels adjacent to fused vertebrae after anterior cervical fusion. One hundred six patients with cervical spondylotic myeloradiculopathy (88 men, 18 women) were followed for an average of 8.5 years. The average age at follow-up was 64 years. Forty-two patients underwent a single-level fusion, 52 had a two-level fusion, and 12 had three levels fused. Seventeen patients who underwent additional surgery after anterior fusion also were reviewed, with an average follow-up period of 2.9 years. Postoperatively, cervical flexion-extension resulted in significantly increased movement about the vertebral interspace at the upper adjacent level. An increment of posterior slip of the vertebra immediately above the fusion level, with associated spinal canal compromise of less than 12 mm, significantly affected neurologic results. Patients with multilevel fusions notably exhibited these radiographic abnormalities at adjacent levels. Spinal canal stenosis, when associated with dynamic spinal canal stenosis in the vertebra above the fusion level, affected late neurologic results. Results of salvage laminoplasty were not satisfactory. Unnecessarily extended longer fusion must be avoided.

Long-term follow-up studies of open-door expansive laminoplasty for cervical stenotic myelopathy

Follow-up at an average time of 7.8 years postoperatively on open-door expansive laminoplasty (EL) was carried out to determine the long-term results of surgery. Thirty-three patients had ossification of the posterior longitudinal ligament and 18 had cervical spondylotic myelopathy. The average age at operation was 54.7 years. Japanese Orthopaedic Association scores and recovery rates increased during the 3 years after surgery and then plateaued. Radiographically, average spinal canal diameter remained enlarged past 5 years' follow-up. Factors leading to worsening of clinical symptoms included age greater than 60 years (4 patients), loss of sagittal canal diameter (2 patients), progression of ossification (4 patients), and minor trauma (1 patient). Postoperative motor paresis due to C5 and C6 root damage recovered to 4 (manual muscle testing) in all patients within 6 years. The conclusion is that open-door EL is safe and leads to good results that are maintained for over 5 years.

A population-based study of malignant spinal cord compression in Ontario

DESIGN

Population-based cohort study.

BACKGROUND

Malignant spinal cord compression (MSCC) has long been recognized as an important complication of cancer, but its incidence is unknown.

OBJECTIVES

To describe the incidence, the management, and the outcome of MSCC in the cancer population of the Canadian province of Ontario.

METHODS

Episodes of MSCC, and treatments used for each episode, were identified by linking electronic hospital separation records and cancer centre records to Ontario's population-based cancer registry. The cumulative frequency of MSCC in the last 5 years of life was described in the 121435 patients who died of cancer in Ontario between 1990 and 1995. Survival after the first episode of MSCC, and duration of hospitalization with MSCC, was described.

RESULTS

The cumulative probability of experiencing at least one episode of MSCC in the 5 years preceding death from cancer was 2.5% overall, and ranged from 0.2% in cancer of the pancreas to 7.9% in myeloma. Overall, 60.2% of first episodes of MSCC were treated with primary radiotherapy, and 16.1% with surgery +/- postoperative radiotherapy, while in the remaining 23.7%, there was no record of radiotherapy or surgery. Overall, the median survival following the first episode of MSCC was 2.9 months. The diagnosis of MSCC was associated with a doubling of the time spent in hospital in the last year of life.

CONCLUSION

MSCC is a fairly common occurrence among patients dying of cancer. There is a 40-fold variation in the cumulative incidence of MSCC among different types of cancer.

A profile of metastatic carcinoma of the spine

Metastatic bone disease in 322 patients was analyzed to assess the frequency and behavior of disseminated carcinoma to the vertebral column. Breast, lung, and prostate neoplasms were the most frequent tumors of origin in the 55% of patients who had vertebral lesions. The lumbar spine was the site of the greatest number of metastases. Back pain did not occur in 36% of the 179 patients with spinal disease. Cord compression occurred in 20% of the patients with vertebral involvement, and prostate tumors were the most frequent neoplasm to cause epidural spinal cord impingement. Hypernephroma was the most common cancer to present as a neurologic deficit secondary to an undetected primary malignancy.

Magnetic resonance imaging study on the results of surgery for cervical compression myelopathy

The morphologic changes and signal intensity of the spinal cord on preoperative magnetic resonance images were correlated with postoperative outcomes in 74 patients undergoing decompressive cervical surgery for compressive myelopathy. The transverse area of the spinal cord on T1-weighted images at the level of maximum compression was closely correlated with the severity of myelopathy, duration of disease, and recovery rate as determined by the Japanese Orthopaedic Association score. In patients with ossification of the posterior longitudinal ligament or cervical spondylotic myelopathy, the increased intramedullary T2-weighted magnetic resonance imaging signal at the site of maximal cord compression and duration of disease significantly influenced the rate of recovery. A multiple regression equation was then developed with these three variables to predict surgical outcomes.

Operative treatment of 733 patients with acute thoracolumbar spinal injuries: comprehensive results from the second, prospective, Internet-based multicenter study of the Spine Study Group of the German Association of Trauma Surgery

The second, internet-based multicenter study (MCSII) of the Spine Study Group of the German Association of Trauma Surgery (Deutsche Gesellschaft für Unfallchirurgie) is a representative patient collection of acute traumatic thoracolumbar (T1-L5) injuries. The MCSII results are an update of those obtained with the first multicenter study (MCSI) more than a decade ago. The aim of the study was to assess and bring into focus: the (1) epidemiologic data, (2) surgical and radiological outcome, and (3) 2-year follow-up (FU) results of these injuries. According to the Magerl/AO classification, there were 424 (57.8%) compression fractures (A type), 178 (24.3%) distractions injuries (B type), and 131 (17.9%) rotational injuries (C type). B and C type injuries carried a higher risk for neurological deficits, concomitant injuries, and multiple vertebral fractures. The level of injury was located at the thoracolumbar junction (T11-L2) in 67.0% of the case. 380 (51.8%) patients were operated on by posterior stabilization and instrumentation alone (POSTERIOR), 34 (4.6%) had an anterior procedure (ANTERIOR), and 319 (43.5%) patients were treated with combined posteroanterior surgery (COMBINED). 65% of patients with thoracic (T1-T10) and 57% with lumbar spinal (L3-L5) injuries were treated with a single posterior approach (POSTERIOR). 47% of the patients with thoracolumbar junction (T11-L2) injuries were either operated from posterior or with a combined posterior-anterior surgery (COMBINED) each. Short angular stable implant systems have replaced conventional non-angular stable instrumentation systems to a large extent. The posttraumatic deformity was restored best with COMBINED surgery. T-spine injuries were accompanied by a higher number and more severe neurologic deficits than TL junction or L-spine injuries. At the same time T-spine injuries showed less potential for neurologic recovery especially in paraplegic (Frankel/AISA A) patients. 5% of all patients required revision surgery for perioperative complications. Follow-up data of 558 (76.1%) patients were available and collected during a 30-month period from 1 January 2004 until 31 May 2006. On average, a posterior implant removal was carried out in a total of 382 COMBINED and POSTERIOR patients 12 months after the initial surgery. On average, the rehabilitation process required 3-4 weeks of inpatient treatment, followed by another 4 months of outpatient therapy and was significantly shorter when compared with MCSI in the mid-1990s. From the time of injury until FU, 80 (60.6%) of 132 patients with initial neurological deficits improved at least one grade on the Frankel/ASIA Scale; 8 (1.3%) patients deteriorated. A higher recovery rate was observed for incomplete neurological injuries (73%) than complete neurological injuries (44%). Different surgical approaches did not have a significant influence on the neurologic recovery until FU. Nevertheless, neurological deficits are the most important factors for the functional outcome and prognosis of TL spinal injuries. POSTERIOR patients had a better functional and subjective outcome at FU than COMBINED patients. However, the posttraumatic radiological deformity was best corrected in COMBINED patients and showed significantly less residual kyphotic deformity (biseg GDW -3.8° COMBINED vs. -6.1° POSTERIOR) at FU (p = 0.005). The sagittal spinal alignment was better maintained when using vertebral body replacement implants (cages) in comparison to iliac strut grafts. Additional anterior plate systems did not have a significant influence on the radiological FU results. In conclusion, comprehensive data of a large patient population with acute thoracolumbar spinal injuries has been obtained and analyzed with this prospective internet-based multicenter study. Thus, updated results and the clinical outcome of the current operative treatment strategies in participating German and Austrian trauma centers have been presented. Nevertheless, it was not possible to answer all remaining questions to contradictory findings of the subjective, clinical outcome and corresponding radiological findings between different surgical subgroups. Randomized-controlled long-term investigations seem mandatory and the next step in future clinical research of Spine Study Group of the German Trauma Society.

Primary and secondary osteoporosis' incidence of subsequent vertebral compression fractures after kyphoplasty

STUDY DESIGN

Retrospective review of prospective database.

OBJECTIVES

Define the incidence of adjacent and remote fractures after kyphoplasty vertebral augmentation, and identify vulnerable subpopulations at increased risks.

SUMMARY OF BACKGROUND DATA

Painful osteoporotic compression fractures can be effectively treated with methyl methacrylate vertebral augmentation, but the effect of intervention on the generation of future remote and adjacent fractures has not been identified. No paper has analyzed the association of long-term steroid use to subsequent compression fractures.

METHODS

A total of 175 patients were treated for compression fractures, from October 1999 to November 2001, 60 patients were excluded due to insufficient follow-up (less than 3 months) or malignancy related fracture. The remaining 115 patients' charts and radiographs were then individually analyzed. New fractures were identified based on changes from baseline imaging studies (). Demographic information, vertebral levels treated, adjacent fractures, and remote fractures underwent statistical analyzed (P < 0.05).

RESULTS

A total of 225 vertebral bodies were treated in 115 patients using the kyphoplasty technique; of those, 26 patients developed 34 subsequent compression fractures. The mean follow-up was 11 months (range, 3-33 months). The incidence of subsequent fracture per procedure per kyphoplasty was 15.1% (34 of 225), overall incidence per patient was 22.6% (26 of 115). There were 80 patients with primary osteoporosis and 35 patients with secondary steroid-induced osteoporosis. These populations were similar in terms of demographics, single or multiple sites, along with two or three adjacent levels treated. Seventeen of the 26 (65%) patients with subsequent fracture had secondary steroid-induced osteoporosis, while only 9 of the 26 (35%) patients had primary osteoporosis. Therefore, the incidence of post-kyphoplasty VCF in the primary osteoporotic patient was 11.25% (9 of 80) and the incidence in the steroid-induced osteoporotic patient was 48.6% (17 of 35). This increased fracture rate in the steroid-dependent patients was significant (P < 0.0001), along with adjacent fractures (12 of 19 on steroids, P = 0.0009), and remote fractures (7 of 9 on steroids, P = 0.027).

CONCLUSIONS

Steroid-induced compression fractures appear to have an increased incidence of subsequent fractures after the kyphoplasty procedure. The kyphoplasty protocol with concurrent medical osteoporotic regimen does not appear to increase, and may serve to reduce, the incidence of remote and adjacent fractures for primary osteoporotic fractures.

Incidence and outcomes of spinal cord injury clinical syndromes

BACKGROUND/OBJECTIVE

To examine and compare demographics and functional outcomes for individuals with spinal cord injury (SCI) clinical syndromes, including central cord (CCS), Brown-Sequard (BSS), anterior cord (ACS), posterior cord (PCS), cauda equina (CES), and conus medullaris (CMS).

DESIGN

Retrospective review.

SETTING

Tertiary care, level 1 trauma center inpatient rehabilitation unit.

PARTICIPANTS

Eight hundred thirty-nine consecutive admissions with acute SCIs.

MAIN OUTCOMES MEASURES

Functional independence measure (FIM), FIM subgroups (motor, self-care, sphincter control), length of stay (LOS), and discharge disposition.

RESULTS

One hundred seventy-five patients (20.9%) were diagnosed with SCI clinical syndromes. CCS was the most common (44.0%), followed by CES (25.1%) and BSS (17.1%). Significant differences (P < or = 0.01) were found between groups with regard to age, race, etiology, total admission FIM, motor admission FIM, self-care admission and discharge FIM, and LOS. Statistical analysis between tetraplegic BSS and CCS revealed significant differences (P < or = 0.01) with respect to age (39.7 vs 53.2 years) and a trend toward significance (P < or = 0.05) with regard to self-care admission and discharge FIM. No significant differences (P < or = 0.01) were found when comparing CMS to CES.

CONCLUSIONS

SCI clinical syndromes represent a significant proportion of admissions to acute SCI rehabilitation, with CCS presenting most commonly and representing the oldest age group with the lowest admission functional level of all SCI clinical syndromes. Patients with cervical BSS seem to achieve higher functional improvement by discharge compared with patients with CCS. Patients with CMS and CES exhibit similar functional outcomes. Patients with ACS and PCS show functional gains with inpatient rehabilitation, with patients with ACS displaying the longest LOS of the SCI clinical syndromes. These findings have important implications for the overall management and outcome of patients with SCI.

Major intraoperative neurologic deficits in pediatric and adult spinal deformity patients. Incidence and etiology at one institution

STUDY DESIGN

A retrospective study of 1,090 patients undergoing corrective spinal deformity surgery for scoliosis (n = 920), kyphosis (n = 77), or a combination of the two (n = 93) at one institution.

OBJECTIVES

To ascertain the etiologies and incidence of neurologic deficits occurring at the time of surgery.

SUMMARY OF BACKGROUND DATA

Potential etiologies of intraoperative neurologic deficits include cord compression, overdistraction, purely vascular, or a combination.

METHODS

The study group included only patients with useful function of their lower extremities and normal bowel and bladder control, and patients whose surgeries were in spinal cord territory as opposed to purely cauda equina territory.

RESULTS

There were four major neurologic deficits that occurred during surgery. Three of the four deficits were purely vascular in etiology. The fourth may have had a vascular and mechanical etiology. All four patients had anterior and posterior surgery with harvesting of the unilateral convex segmental vessels, and each had a component of hyperkyphosis, as well as intraoperative controlled hypotension. All four patients showed marked improvement of motor weakness with time.

CONCLUSIONS

Significant risk factors were combined anterior and posterior surgery (P = 0.009) and hyperkyphosis (P = 0.0006).

Natural history of skeletal-related events in patients with breast, lung, or prostate cancer and metastases to bone: a 15-year study in two large US health systems

PURPOSE

To document the risk of skeletal complications in patients with bone metastases from breast cancer (BC), lung cancer (LC), or prostate cancer (PC) in routine clinical practice.

METHODS

We used data from two large US health systems to identify patients aged ≥18 years with primary BC, LC, or PC and newly diagnosed bone metastases between January 1, 1995 and December 31, 2009. Beginning with the date of diagnosis of bone metastasis, we estimated the cumulative incidence of skeletal-related events (SREs) (spinal cord compression, pathologic fracture, radiation to bone, bone surgery), based on review of medical records, accounting for death as a competing risk.

RESULTS

We identified a total of 621 BC, 477 LC, and 721 PC patients with newly diagnosed bone metastases. SREs were present at diagnosis of bone metastasis in 22.4, 22.4, and 10.0 % of BC, LC, and PC patients, respectively. Relatively few LC or PC patients received intravenous bisphosphonates (14.8 and 20.2 %, respectively); use was higher in patients with BC, however (55.8 %). In BC, cumulative incidence of SREs during follow-up was 38.7 % at 6 months, 45.4 % at 12 months, and 54.2 % at 24 months; in LC, it was 41.0, 45.4, and 47.7 %; and in PC, it was 21.5, 30.4, and 41.9 %. More than one half of patients with bone metastases had evidence of SREs (BC: 62.6 %; LC: 58.7 %; PC: 51.7 %), either at diagnosis of bone metastases or subsequently.

CONCLUSIONS

SREs are a frequent complication in patients with solid tumors and bone metastases, and are much more common than previously recognized in women with BC.

Trends for Spine Surgery for the Elderly: Implications for Access to Healthcare in North America

The proportion of the population over age 65 in the United States continues to increase over time, from 12% in 2000 to a projected 20% by 2030. There is an associated rise in the prevalence of degenerative spinal disorders with this aging population. This will lead to an increase in demand for both nonsurgical and surgical treatment for these disabling conditions, which will stress an already overburdened healthcare system. Utilization of spinal procedures and services has grown considerably. Comparing 1999 to 2009, lumbar epidural steroid injections have increased by nearly 900,000 procedures performed per year, while physical therapy evaluations have increased by nearly 1.4 million visits per year. We review the literature regarding the cost-effectiveness of spinal surgery compared to conservative treatment. Decompressive lumbar spinal surgery has been shown to be cost-effective in several studies, while adult spinal deformity surgery has higher total cost per quality-adjusted life year gained in the short term. With an aging population and unsustainable healthcare costs, we may be faced with a shortfall of beneficial spine care as demand for spinal surgery in our elderly population continues to rise.

ABBREVIATION

QALY, quality-adjusted life year.

Pediatric Spine Fractures

OBJECTIVE

The anatomy and biomechanics of the growing spine produce failure patterns different from those in adults. Spinal injury in the pediatric patient is a concern as prevention of further neurologic damage and deformity and the good potential for recovery make timely identification and appropriate treatment of such injury critical. A retrospective clinical case series was conducted to present data from a large series of pediatric patients with spine injuries from a single regional trauma center.

METHODS

One hundred thirty-seven children with spine injuries were seen over 10 years and were divided into three age groups: 0-9, 10-14, and 15-17 years. Analysis of variance and chi2 were used to analyze differences between groups.

RESULTS

There were 36 patients aged 0-9, 49 aged 10-14, and 52 aged 15-17. Spine injury incidence increased with age. Motor vehicular accidents were the most common cause in this series. There were 36% cervical, 34% thoracic, 29% lumbar, 34% multilevel contiguous, and 7% multilevel noncontiguous involvement. Nineteen percent had spinal cord injury. Thirteen of 21 complete neurologic injuries and all 3 incomplete injuries improved. Cord injury was more common in the 0-9 age group. Four of five patients with spinal cord injury without radiographic abnormality (SCIWORA) were in the 0-9 age group and had complete neurologic injuries. Young children with cervical injuries were more likely to die than older children. Fifty-three percent had associated injuries. Eighteen percent underwent decompression, fusion, and instrumentation. Two patients developed scoliosis. The complication rate in surgical patients was higher than in patients treated nonsurgically and in polytrauma patients. This may be related to the severity of the initial injury.

CONCLUSIONS

Our results suggest age-related patterns of injury that differ from previous work. The incidence of cord injury is 20% with higher frequencies in the young child. Potential for neurologic recovery is good. Young children have a higher risk for death than older children. There was no predominance of cervical injuries in the young child. The incidence of SCIWORA was low. Higher complication rates were seen in polytrauma and surgical patients.

Predictors of skeletal complications in patients with metastatic breast carcinoma

BACKGROUND

The high rate of incidence of skeletal complications in women with metastatic breast carcinoma appears to contribute significantly to their morbidity. Although recent trials have demonstrated the efficacy of bisphosphonates in preventing skeletal complications in selected patients, to the authors' knowledge the incidence rate of skeletal complications in an unselected population of women with metastatic breast carcinoma is unknown. The current study was designed to examine the incidence rate of skeletal complications in a large unselected group of women with metastatic breast carcinoma to determine predictors of these complications.

METHODS

All women (n = 718) diagnosed with metastatic breast carcinoma between 1981-1991 at the study institution were studied retrospectively.

RESULTS

Greater than 50% of the women developed skeletal complications; among these women, 51% had > 1 complication. Approximately 80% of those with bone-limited disease at the time of diagnosis developed complications, as did 60% of those with bone and visceral disease and 21% of those with no bone disease. By univariate analysis, the site of initial metastatic disease, abnormal alkaline phosphatase, and a disease free interval of < 3 years were predictive of skeletal complications. Multivariate analysis revealed that bone involvement at the time of diagnosis was predictive of subsequent skeletal complications.

CONCLUSIONS

In this large retrospective study with extensive follow-up, skeletal complications were extremely common and repetitive, although complications predated patient death by >/= 1 year in the group of women presenting with any bone disease. The presence of bone disease at the time of initial presentation was predictive of skeletal complications. In this group of patients, the authors were unable to identify a subgroup with a low rate of skeletal complications.

Bone metastases and skeletal-related events in patients with malignant pheochromocytoma and sympathetic paraganglioma

CONTEXT

Bone metastases (BM) can cause severe pain, spinal cord compression, pathological fractures, and/or hypercalcemia. These skeletal-related events (SREs) may cause immobilization, loss of independence, poor quality of life, and reduced survival. There is limited information on the clinical effects of BM and SREs in patients with malignant pheochromocytoma or sympathetic paraganglioma (PHEO/sPGL).

OBJECTIVES

We studied the prevalence and clinical characteristics of BM and SREs in patients with PHEO/sPGL and investigated the risk factors for SRE development.

DESIGN

Using a large institutional database, we conducted a retrospective study of 128 patients with malignant PHEO/sPGL at The University of Texas MD Anderson Cancer Center from 1967 through 2011.

RESULTS

Of the patients, 91 (71%) had BM, and 57 of these (63%) developed metachronous BM at a median time of 3.4 years (range, 5 months to 23 years) after the primary tumor diagnosis. Metastatic disease was confined exclusively to the skeleton in 26 of 128 (20%) patients. Sufficient information to assess SRE occurrence was available for 67 patients, and 48 of 67 (72%) patients had at least 1 SRE. The median overall survival for the 128 patients was 12 years for patients with only BM, 7.5 years for patients with nonosseous metastases, and 5 years for patients with both BM and nonosseous metastases (log rank test P value = .005). We were unable to identify factors predictive of SRE development, but the occurrence of a first SRE was associated with the development of subsequent SREs in 48% of subjects. In responsive patients, the use of systemic therapy was associated with fewer SREs (P < .0001).

CONCLUSIONS

BM and SREs are frequent in patients with malignant PHEO/sPGL. SREs often develop shortly after the diagnosis of BM; severe pain is the most frequent SRE. These patients should be followed long-term by a multidisciplinary team to promptly identify the need for medical or surgical intervention.

Cost-effectiveness of surgery plus radiotherapy versus radiotherapy alone for metastatic epidural spinal cord compression

PURPOSE

A recent randomized clinical trial has demonstrated that direct decompressive surgery plus radiotherapy was superior to radiotherapy alone for the treatment of metastatic epidural spinal cord compression. The current study compared the cost-effectiveness of the two approaches.

METHODS AND MATERIALS

In the original clinical trial, clinical effectiveness was measured by ambulation and survival time until death. In this study, an incremental cost-effectiveness analysis was performed from a societal perspective. Costs related to treatment and posttreatment care were estimated and extended to the lifetime of the cohort. Weibull regression was applied to extrapolate outcomes in the presence of censored clinical effectiveness data.

RESULTS

From a societal perspective, the baseline incremental cost-effectiveness ratio (ICER) was found to be $60 per additional day of ambulation (all costs in 2003 Canadian dollars). Using probabilistic sensitivity analysis, 50% of all generated ICERs were lower than $57, and 95% were lower than $242 per additional day of ambulation. This analysis had a 95% CI of -$72.74 to 309.44, meaning that this intervention ranged from a financial savings of $72.74 to a cost of $309.44 per additional day of ambulation. Using survival as the measure of effectiveness resulted in an ICER of $30,940 per life-year gained.

CONCLUSIONS

We found strong evidence that treatment of metastatic epidural spinal cord compression with surgery in addition to radiotherapy is cost-effective both in terms of cost per additional day of ambulation, and cost per life-year gained.

Predictability of operative results of cervical compression myelopathy based on preoperative computed tomographic myelography

The transverse area and flattening ratio of the spinal cord were determined with preoperative computed tomographic myelography in 103 patients with cervical compression myelopathy: cervical spondylotic myelopathy (n = 44); ossification of the posterior longitudinal ligament (n = 39); and cervical disc herniation (n = 20). With these values and other clinical items (eg, age, duration of symptoms, preoperative severity), a linear model to predict postoperative recovery was attempted by multiple regression analysis. In cervical spondylotic myelopathy and ossification of the posterior longitudinal ligament, the transverse area of the spinal cord and the duration of symptoms were accepted as effective explanatory variables to predict recovery. In cervical disc herniation, regardless of the transverse area or duration, the recovery was good, and pathologic state was considered essentially different.

Prevalence and pattern of major neurological disorders in rural Kashmir (India) in 1986

In 1986 in the Kuthar Valley in the Anantnag District of south Kashmir (northwestern India), we studied the population to ascertain the prevalence and pattern of various neurological diseases. A house-to-house survey was done in a rural population of 63,645 (according to a World Health Organization protocol, 1981). 616 cases of major neurological disorders were detected, yielding a prevalence of ratio of 9.67/1,000 as of prevalence day November 1, 1986. The prevalence ratios for various common neurological disorders were: epilepsy 2.47/1,000; stroke 1.43/1,000; paralytic poliomyelitis 2.18/1,000; mental retardation 2.09/1,000; deaf mutism 1.63/1,000, and cerebral palsy 1.24/1,000. Persons with these conditions constituted 92% of all neurological cases. Patients with motor neuron disease, Alzheimer's dementia or multiple sclerosis were not found.

Effect of age and loading rate on human cervical spine injury threshold

STUDY DESIGN

Statistical analysis of human cadaver cervical spine compression experiments.

OBJECTIVES

To quantify the cervical spine compressive injury threshold as a function of the person's age, gender, and external loading rate.

SUMMARY OF BACKGROUND DATA

Results of epidemiologic studies have indicated that most survivors of cervical spinal cord injury have spinal column fractures and dislocations that result from a compression or compression-flexion force vector. Cervical spinal column injury thresholds are dependent on many factors. Delineation of the injury thresholds according to age, gender, and loading rate is necessary to improve clinical assessments and prevention strategies.

METHODS

Twenty-five human cadaver head-neck compression tests were included in the analysis. Two statistical models were used to quantify the effects of age, gender, and loading rate on the force required to induce failure in the cervical spine. A multiple linear regression model provided a direct equation that quantified the effects of the variables, and a proportional hazards model was used to quantify probability of injury with each factor.

RESULTS

The regression model had a correlation coefficient of 0.87. There was an interactive effect between age and loading rate: Increasing age reduced the effect of loading rate and at approximately 82 years, loading rate had no effect. Men were consistently 600 N stronger than women. The 50% probability of failure for a 50-year-old man at a 4.5-m/sec loading rate was approximately 3.9 kN. Differences in probability curves followed the same trends as seen in the regression model.

CONCLUSIONS

The effects of age on cervical spine injury threshold are coupled with the rate of loading experienced through the external force vector that causes the trauma. Assessment of injury mechanisms and thresholds should be based on the person's age, gender, and loading rate to determine treatment and prevent injuries.

Epidemiology of cauda equina and conus medullaris lesions

The epidemiology of cauda equina and conus medullaris lesions is not well known, and this study aimed to provide further information on this topic. In the period 1996-2004, patients fulfilling the clinical, electrodiagnostic, and radiological criteria for such lesions were identified. For cauda equina/conus medullaris lesions an annual incidence rate of 3.4/1.5 per million, and period prevalence of 8.9/4.5 per 100,000 population were calculated. The values obtained are probably valid estimates of the incidence and prevalence of these lesions in developed countries.

Risk factor for unsatisfactory outcome after lumbar foraminal and far lateral microdecompression

STUDY DESIGN

A retrospective study of consecutive patients who underwent microdecompression for far lateral disc or foraminal stenosis.

OBJECTIVES

To evaluate the risk factors for unsatisfactory outcome.

SUMMARY OF BACKGROUND DATA

There has been no detailed analysis of postoperative radicular pain, although it is not infrequent following foraminal and far lateral microdecompression.

METHODS

A total of 184 patients, who were followed up for more than 2 years, were reviewed. Microdecompression was performed through lateral intermuscular approach. In cases of double herniation (combination of intracanalicular disc at the same level), additional intracanalicular decompression was simultaneously performed. The unsatisfactory outcomes included persistent or recurrent leg pain, based on the Japanese Orthopedic Association leg pain score, and revision surgery at the same level. The potential risk factors, including gender, age, symptom period, preoperative radiologic and intraoperative findings, were determined.

RESULTS

The average follow-up period was 38.4 months, with a maximum 70 months. Forty of the 184 patients (21.7%) had persistent or recurrent leg pain, with nine requiring revision surgeries. The statistically significant risk factor for unfavorable outcomes was double herniation, with odds ratio of 2.89 (P = 0.004).

CONCLUSION

Facet preserving microdecompression is an effective method for foraminal and far lateral root compression. However, in cases of double herniation, total facetectomy is preferable.

Evidence-based review of the surgical management of vertebral column metastatic disease

Object

Significant controversy exists over the most appropriate treatment for patients with metastatic disease of the vertebral column. Treatment options include surgical intervention, radiotherapy, or a combination of the two; nevertheless, a standard of care that yields the best survival, outcome, and quality of life has not been established. The purpose of this review was to determine the foundation in the literature of views favoring surgical intervention for spinal metastatic disease.

Methods

A search of the English-language literature published between 1964 and 2003 was performed for the subject of spinal metastatic disease. Papers were selected based on the inclusion criteria described, and evidentiary information was compiled and graded using previously described methods.

Conclusions

Although there is insufficient evidence to support a standard for surgical treatment in patients with metastatic spinal disease, the authors present guidelines and recommendations based on the evidence provided by the current literature.

Anterior decompression and fusion versus posterior laminoplasty for multilevel cervical compressive myelopathy

The optimal surgical strategy for anterior or posterior approaches remains controversial for multilevel cervical compressive myelopathy caused by multisegment cervical spondylotic myelopathy (MCSM) or ossification of the posterior longitudinal ligament (OPLL). A systematic review and meta-analysis was conducted evaluating the clinical results of anterior decompression and fusion (ADF) compared with posterior laminoplasty for patients with multilevel cervical compressive myelopathy. PubMed, Embase, and the Cochrane Library were searched for randomized controlled trials and nonrandomized cohort studies conducted from 1990 to May 2013 comparing ADF with posterior laminoplasty for the treatment of multilevel cervical compressive myelopathy due to MCSM or OPLL. The following outcome measures were extracted: Japanese Orthopedic Association (JOA) score, recovery rate, complication rate, reoperation rate, blood loss, and operative time. Subgroup analysis was conducted according to the mean number of surgical segments. Eleven studies were included in the review, all of which were prospective or retrospective cohort studies with relatively low quality indicated by GRADE Working Group assessment. A definitive conclusion could not be reached regarding which surgical approach is more effective for the treatment of multilevel cervical compressive myelopathy. Although ADF was associated with better postoperative neural function than posterior laminoplasty in the treatment of multilevel cervical compressive myelopathy due to MCSM or OPLL, there was no apparent difference in the neural function recovery rate between the 2 approaches. Higher rates of surgery-related complication and reoperation should be taken into consideration when ADF is used for patients with multilevel cervical compressive myelopathy. The surgical trauma associated with corpectomy was significantly higher than that associated with posterior laminoplasty.

Cervical spondylotic myelopathy in elderly people: a high incidence of conduction block at C3-4 or C4-5

OBJECTIVES

To precisely localise the site of conduction block in elderly patients with cervical spondylotic myelopathy in the presence of multilevel compression shown by MRI.

METHODS

A total of 44 patients aged 65 and older underwent serial intervertebral recording of spinal somatosensory evoked potentials (SSEPs) from either the intervertebral disc or the ligamentum flavum after epidural stimulation. The site of conduction block identified by abrupt reduction in size of the negative peak was designated as the 0 level with the other levels numbered in order of distance assigning a minus sign caudally.

RESULTS

A single site of focal conduction block was disclosed in 42 patients, 23 (55%) at C3-4, 17 (40%) at C4-5, and two (5%) at C5-6. At these levels (0), the amplitude of the negative component was reduced (p<0.0001) to 29% and the area to 22%, with a concomitant increase (p<0.0001) of the initial positive component to 150% in amplitude and 293% in area as compared to the-2 level which was taken as the baseline (100%).

CONCLUSIONS

A high incidence (95%) of focal conduction block at C3-4 or C4-5 with normal conduction at C5-6 and C6-7 characterises cervical spondylotic myelopathy in elderly people. Incremental SSEP studies documenting the site of conduction block will help exclude clinically silent cord compression, directing the surgical intervention to the appropriate level of concern.

Interobserver and intraobserver reliability of maximum canal compromise and spinal cord compression for evaluation of acute traumatic cervical spinal cord injury

STUDY DESIGN

Prospective, blinded validation study of an objective, quantitative measure to assess maximum canal compromise (MCC) and maximum spinal cord compression (MSCC) in individuals with acute cervical spinal cord injury (SCI).

OBJECTIVE

To examine the intraobserver and interobserver reliability of MCC and MSCC in individuals with acute traumatic cervical SCI.

SUMMARY OF BACKGROUND DATA

To date, few quantitative reliable radiologic methods for assessing the extent of spinal cord compression in the setting of acute SCI have been reported. MCC and MSCC, as assessed on mid-sagittal CT and T2-weighted MR images, respectively, appear to have potential clinical and prognostic value. To date, the validation of these assessment tools has been limited to a small number of observers at a single institution. However, to date no study has focused on the reliability of these radiologic parameters among a large cohort of spine surgeons from North America and abroad. This type of validation is critical to allow the broader use of these outcome measures in research studies and in clinical practice.

METHODS

Mid-sagittal MRI and CT images of cervical spine were selected from 10 individuals with acute traumatic cervical SCI. A total of 28 spine surgeons independently estimated CT MCC, T1-weighted MRI MCC, and T2-weighted MRI MSCC on two occasions using a calibrated ruler. In the first round of measurements, the observers estimated the radiologic parameters using only written instructions. The second measurement set was obtained after an interactive teaching session on the methodology. The order of the images was altered for the second set of measurements.

RESULTS

Analysis using parametric and nonparametric statistics indicated high intraobserver reliability for CT MCC, T1-weighted MRI MCC, and T2-weighted MSCC with interclass correlation coefficients (ICCs) of 0.92, 0.95, and 0.97, respectively. The interobserver reliability for all three radiologic parameters was considered moderate with ICCs ranging from 0.35 to 0.56.

CONCLUSION

Our results indicate that the intraobserver reliability for the MCC and MSCC was high. Although the interobserver reliability for all three radiologic parameters in the present study was below 0.75, the observed differences were small and largely accounted for by the limitations in the precision of the calibrated ruler. For cases with minimal cord compression, the measurement of canal stenosis (MCC) proved more accurate. In contrast, in cases with severe cord compression, the assessment of MSCC was more accurate. It is anticipated that the use of digital imaging technologies will further enhance the precision of these outcome measures.