miR-10396b-3p inhibits mechanical stress-induced ligamentum flavum hypertrophy by targeting IL-11.

Ligamentum flavum hypertrophy (LFH) leads to lumbar spinal stenosis (LSS) caused by LF tissue inflammation and fibrosis. Emerging evidence has indicated that dysregulated microRNAs (miRNAs) have an important role in inflammation and fibrosis. Mechanical stress (MS) has been explored as an initiating step in LFH pathology progression; the inflammation-related miRNAs induced after mechanical stress have been implicated in fibrosis pathology. However, the pathophysiological mechanism of MS-miRNAs-LFH remains to be elucidated. Using miRNAs sequencing analysis and subsequent confirmation with qRT-PCR assays, we identified the decreased expression of miR-10396b-3p and increased expression of IL-11 (interleukin-11) as responses to the development of LSS in hypertrophied LF tissues. We also found that IL-11 is positively correlated with fibrosis indicators of collagen I and collagen III. The up-regulation of miR-10396b-3p significantly decreased the level of IL-11 expression, whereas miR-10396b-3p down-regulation increased IL-11 expression in vitro. Luciferase reporter assay indicates that IL-11 is a direct target of miR-10396b-3p. Furthermore, cyclic mechanical stress inhibits miR-10396b-3p and induces IL-11, collagen I, and collagen III in vitro. Our results showed that overexpression of miR-10396b-3p suppresses MS-induced LFH by inhibiting collagen I and III via the inhibition of IL-11. These data suggest that the MS-miR-10396b-3p-IL-11 axis plays a key role in the pathological progression of LFH.

Prophylactic Decompression for Cervical Stenosis in Jeune Syndrome: Report From a Single Institution.

STUDY DESIGN: This is a level IV retrospective descriptive study at a single institution. OBJECTIVE: The objective of the study was to determine the preoperative signs or symptoms prompting cervicomedullary imaging in Jeune syndrome. SUMMARY OF BACKGROUND DATA: Jeune syndrome is a rare autosomal recessive disorder that results in pulmonary compromise from abnormal development of the thorax. Multiple medical comorbidities complicate timely diagnosis of cervicomedullary stenosis, which neurologically jeopardizes this patient population with regards to improper cervical manipulation. Currently, explicit screening of the cervicomedullary junction is not advocated in national guidelines. METHODS: The User Reporting Workbench and Center for Thoracic Insufficiency Syndrome (CTIS) Safety Registry was queried for patients with Jeune syndrome under the age of 18 with cervicomedullary stenosis with or without suboccipital craniectomy/craniotomy evaluated at the authors' institution from January 1, 2007 to August 21, 2018. The primary outcome was the clinical reason for cervicomedullary screening. Secondary outcomes were: age at time of surgery, preoperative myelopathy (spasticity, urinary retention), hydrocephalus, postoperative deficits (respiratory, motor, swallowing difficulty), and need for cervical fusion. RESULTS: Of 32 patients with Jeune syndrome, four (12.5%) had cervicomedullary stenosis requiring decompression. The average age at surgery was 5.25 months (2-9 mo). Two patients underwent imaging due to desaturation events while the other two patients were diagnosed with cervical stenosis as an incidental finding. No patients exhibited clinical myelopathy. Two patients had baseline preoperative swallowing difficulties. None of the patients postoperatively required cervical fusions, nor did they exhibit respiratory deficits, motor deficits, or worsening swallowing difficulties. CONCLUSION: Jeune patients should be routinely screened for cervicomedullary stenosis and undergo subsequent prophylactic decompression to minimize or eliminate the development of irreversible neurologic compromise. LEVEL OF EVIDENCE: 4.

Loco-check presents a useful tool to determine health-related quality of life in elderly people with lumbar spinal stenosis.

BACKGROUND: Locomotive syndrome (LS) is a condition of decreased mobility caused by disorders of the locomotive organs. Lumbar spinal stenosis (LSS) is an LS disorder. The loco-check is a simple questionnaire comprising seven questions that can detect LS. The differences between the health-related quality of life (HRQoL) of elderly persons without LSS and those with LSS remain unclear. The primary aim of this study was to clarify these differences using the European quality of life (EuroQoL) scale. The secondary aim was to clarify the differences between the groups based on loco-check questionnaire responses. METHODS: We recruited patients aged ≥65 years. Our age- and sex-matched case/control cohorts included 28 elderly patients with LSS and 28 without LSS. The study participants were evaluated by the number of "yes" answers on the loco-check, the HRQoL using EuroQoL-5 dimension (EQ-5D) utility values, and the EuroQoL-visual analog scale (EQ-VAS). We compared differences between patients with and without LSS regarding HRQoL using EQ-5D utility values, EQ-VAS scores, the number of "yes" answers on the loco-check, and details of the loco-check. RESULTS: Patients with LSS had significantly lower EQ-5D utility values (p < 0.01) and more "yes" answers on the loco-check (p < 0.01) than those without LSS. There were no significant differences in EQ-VAS scores between groups (p = 0.09). There were statistically significant differences between groups in all questions except two: You often trip up or slip around the house and You can't make it across the road before the light turns red. CONCLUSIONS: Elderly patients with LSS had lower EQ-5D utility values and more "yes" answers on the loco-check than elderly persons without LSS. Our results may clarify differentiating features of elderly patients with and without LSS.

[PEEK cage fusion after anterior cervical corpectomy : Clinical and radiological results in patients with spondylotic myelopathy]. / PEEK-Cage-Fusion nach anteriorer zervikaler Korporektomie : Klinische und radiologische Ergebnisse bei spondylotischer Myelopathie.

BACKGROUND: Anterior cervical corpectomy and fusion (ACCF) has become a standard procedure for patients with spondylotic myelopathy due to multisegmental stenosis of the cervical canal. In addition to the fusion technique using autogenous bone grafts and titanium implants, synthetic polyetheretherketone (PEEK) cages have been used increasingly during the last years. However, limited evidence on the clinical and radiological results of PEEK cages for ACCF exists in the literature. The study presented here is the largest series to date reporting clinical and radiological outcome as well as complication rates after one to three-level ACCF using PEEK cages augmented by an anterior plate-screw osteosynthesis. MATERIALS AND METHODS: Retrospective study on 101 patients after stand-alone PEEK cage-ACCF with a minimum follow-up of 6 months. The number of hardware failures and implant-related surgical revisions were determined. The rate of subsidence and fusion and the course of lordotic alignment were analysed. The neck disability index (NDI) and the European myelopathy score (EMS) were assessed. RESULTS: Screw complications were detected in 8/101 cases and 3 cases of cage dislocation occurred, resulting in an overall implant related revision rate of 2.9 % (all revision cases showed cage dislocation). The rate of cage subsidence >3 mm was 12 % and solid fusion was achieved in 82 % of the patients. NDI, EMS and lordotic alignment improved significantly. CONCLUSIONS: PEEK cages are a safe and effective alternative to titanium cages or autogenous bone graft for ACCF. Further randomized evaluation of different fusion techniques in ACCF is still necessary.

Minimally Invasive Tubular Resection of Lumbar Synovial Cysts: Report of 40 Consecutive Cases.

BACKGROUND: Lumbar synovial cysts are a relatively common clinical finding. Surgical treatment of symptomatic synovial cysts includes computed tomography-guided aspiration, open resection and minimally invasive tubular resection. We report our series of 40 consecutive minimally invasive microscopic tubular lumbar synovial cyst resections. METHODS: Following Institutional Review Board approval, a retrospective analysis of 40 cases of minimally invasive microscopic tubular retractor synovial cyst resections at a single institution by a single surgeon (B.D.B.) was conducted. Gross total resection was performed in all cases. RESULTS: Patient characteristics, surgical operating time, complications, and outcomes were analyzed. Lumbar radiculopathy was the presenting symptoms in all but 1 patient, who presented with neurogenic claudication. The mean duration of symptoms was 6.5 months (range, 1-25 months), mean operating time was 58 minutes (range, 25-110 minutes), and mean blood loss was 20 mL (range, 5-50 mL). Seven patients required overnight observation. The median length of stay in the remaining 33 patients was 4 hours. There were 2 cerebrospinal fluid leaks repaired directly without sequelae. The mean follow-up duration was 80.7 months. Outcomes were good or excellent in 37 of the 40 patients, fair in 1 patient, and poor in 2 patients. CONCLUSIONS: Minimally invasive microscopic tubular retractor resection of lumbar synovial cysts can be done safely and with comparable outcomes and complication rates as open procedures with potentially reduced operative time, length of stay, and healthcare costs. Patient selection for microscopic tubular synovial cyst resection is based in part on the anatomy of the spine and synovial cyst and is critical when recommending minimally invasive vs. open resection to patients.

Body Mass Index and Risk for Clinical Lumbar Spinal Stenosis: A Cohort Study.

STUDY DESIGN: A prospective cohort study that used a Swedish nationwide occupational surveillance program for construction workers (period of registration from 1971 to 1992). In all, 364,467 participants (mean age at baseline 34 yr) were included in the study. OBJECTIVE: To determine whether overweight and obesity are associated with a higher risk of lumbar spinal stenosis (LSS). SUMMARY OF BACKGROUND DATA: During recent decades, LSS has become the most common indication for spine surgery, a change that coincides with a higher prevalence of obesity. METHODS: A diagnosis of LSS was collected through individual linkage to the Swedish National Patient Register through December 31, 2011. Poisson regression models were employed to estimate multivariable-adjusted incidence rate ratios (IRRs) for LSS. RESULTS: At baseline, 65% had normal weight (BMI [body mass index]: 18.5-24.99 kg/m), 29% were overweight (BMI: 25-29.99 kg/m), 5% were obese (BMI ≥30 kg/m), and 2% were underweight (BMI <18.5 kg/m). During 11,190,944 person-years of follow-up, with a mean of 31 years, 2381 participants were diagnosed with LSS. Compared with normal weight individuals, obese workers had an IRR of 2.18 (95% confidence interval, 1.87-2.53) for LSS and overweight workers had an IRR of 1.68 (95% confidence interval, 1.54-1.83). Workers who were underweight halved their risk of LSS (IRR: 0.52, 95% confidence interval, 0.30-0.90). CONCLUSION: Obese and overweight persons are at a higher risk of developing LSS. Furthermore, our results indicate that obesity might be a novel explanation for the increased number of patients with clinical LSS. LEVEL OF EVIDENCE: 3.

An unexpectedly progressed lumbar herniated disk.

The authors describe a case of a 26-year-old female military veteran who presented with low back pain that she attributed to a recent foot injury. The patient reported a history of lumbar pain while in the military that had been treated successfully with high-velocity, low-amplitude osteopathic manipulative treatment. The patient's current pain was improved with osteopathic manipulative treatment and gait correction. Several weeks after her initial presentation, the patient reported that she had had a herniated disk diagnosed 2 years earlier by means of magnetic resonance imaging. Updated magnetic resonance imaging was performed, the results of which revealed a large herniated disk that had caused severe stenosis. The patient was immediately referred to a neurosurgeon for consultation and subsequently underwent surgical treatment.

Long-term follow-up of revision decompressive lumbar spinal surgery in elderly patients.

STUDY DESIGN: A retrospective study of elderly patients (more than 65 y of age) who underwent surgery for lumbar spinal stenosis between 1990 and 2000 was carried out. Among all these patients, the patients who underwent revision surgery were studied. OBJECTIVE: To quantify the risk of reoperation in patients who underwent decompressive lumbar surgery and to analyze the connection between different variables before the primary surgery to the risk of surgical revision. SUMMARY OF BACKGROUND DATA: Lumbar decompressive spinal surgery is a very common procedure. However, the tendency of restenosis with clinical effect on the patients increases with time. Outcome studies reported that rate of reoperation has ranged from 0% to 23%. No studies so far analyzed the rate of reoperation in elderly patients in long-term follow-up and the different variables that contributed to it. METHODS: Between 1990 and 2000, 357 patients more than 65 years of age underwent decompressive surgery for lumbar spinal stenosis with a mean follow-up of 64 months. Thirty-one patients (8.7%) were reoperated at least once. Twenty-five of them (81%) were followed. Demographic data, body mass index, associated comorbidities, preoperative risk as assessed by the scale of the American Society of Anesthesiology, type of surgery, pain perception by Visual Analog Scale, duration of symptoms, clinical presentation, walking ability (distance in meters), the level of basic activities of daily living was evaluated by the Barthel index, and overall satisfaction from the surgery were recorded and analyzed. For comparison between the reoperated patients and patients who were not reoperated, another group of 25 patients who were not reoperated (of our cohort) was studied. These patients were matched to the reoperated patients in terms of age (±2 y), sex, body mass index, and time elapsed since surgery (±3 mo). RESULTS: Overall rate of revision surgery was 8.7% in a period of 70 months follow-up. Twenty-one patients (80%) underwent 1 revision surgery, 4 patients (16%) underwent 2 revisions, and 1 patient (4%) had 3 revisions. The mean pain-free interval was 26 months. There were no sex differences in the rate of reoperation (10% in females and 7% in males, P>0.05). Although that only 36% of the patients were very or somewhat satisfied with overall revision results, significant improvement in pain perception (change in Visual Analog Scale score of 4.84, P<0.001) and in functional status (Barthel index increased in 15.2 points, P<0.001) were found after revision surgery. Six cases (19%) were operated in the first 2 years, 16 cases (52%) in the first 4 years, 24 cases (77%) in the first 6 years, and additional 7 cases (23%) were reoperated more than 6 years after the first operation. CONCLUSIONS: Even in reoperated elderly patients with spinal stenosis without spinal fusion, an improvement in functional status and somewhat in pain perception can be anticipated.

Long-term follow-up results and radiographic findings of anterior surgery with Cloward trephination for cervical spondylotic myelopathy.

STUDY DESIGN: Serial retrospective long-term follow-up study. OBJECTIVE: To assess the long-term results of anterior surgery with Cloward trephination and iliac strut grafting for cervical spondylotic myelopathy. SUMMARY OF BACKGROUND DATA: Anterior surgery remains the most common surgical option and generally gives good results, although early and late deterioration after initial postoperative improvement has been noted. Although anterior decompression with trephination is a variant of the Cloward technique, little information is available concerning the long-term results after this procedure. METHODS: One hundred sixty-eight consecutive patients treated with this technique by the same author from the years 1978 to 1992 were followed serially. One hundred and seven patients were followed for over 10 years (mean: 14.1 y) (follow-up rate: 71.8%). Clinical results were evaluated according to the Japanese Orthopedic Association system and the results at different postoperative intervals were analyzed. Thirty-six patients returned for the final follow-up. Plain radiographs were taken in neutral and flexion-extension positions and computed tomography scans were taken at fused segments and unfused levels. RESULTS: The mean recovery rate was 56.8% at final follow-up. Deterioration of 2 Japanese Orthopedic Association points or more was experienced in 44 patients at various postoperative periods and was more frequent at over 10 years follow-up. Kyphosis of fused segments was noted frequently on the radiographies of the 36 patients with a mean of 7.8 degrees. A straight or misaligned cervical spine was found in 28 (77.8%) patients and these deformities were more serious in multilevel fusions. Stenosis of the canal at fused segments was found in 15 (41.7%) patients owing to osteogenesis resulting from inadequate decompression or pseudoarthrosis. At unfused levels, the incidence of spondylolisthesis, bony bridge, disc hernia, and thickening or bulging of the ligament flavum was 19.4%, 27.8%, 33.3%, 19.4%, respectively, and these abnormalities almost always occurred at levels adjacent to the fusion. Radiographic abnormalities were pejorative for long-term clinical results. CONCLUSIONS: Anterior surgery with Cloward trephination provides generally acceptable long-term results with considerable incidences of deterioration and radiographic abnormalities. This underlines the need for thorough decompression and preservation of the subchondral endplate bone for solid fusion and maintenance of the cervical lordotic curvature.

Vertebral plate regeneration induced by radiation-sterilized allogeneic bone sheets in sheep.

OBJECTIVE: To evaluate the effects and mechanism of radiation-sterilized allogeneic bone sheets in inducing vertebral plate regeneration after laminectomy in sheep. METHODS: Twelve adult male sheep (aged 1.5 years and weighing 27 kg on average) provided by China Institute for Radiation Protection underwent L3-4 and L4-5 laminectomy. Then they were randomly divided into two groups: Group A (n=6) and Group B (n=6). The operated sites of L4-5 in Group A and L3-4 in Group B were covered by "H-shaped" freeze-drying and radiation-sterilized allogeneic bone sheets (the experimental segments), while the operated sites of L3-4 in Group A and L4-5 in Group B were uncovered as the self controls (the control segments). The regeneration process of the vertebral plate and the adhesion degree of the dura were observed at 4, 8, 12, 16, 20 and 24 weeks after operation. X-ray and CT scan were performed in both segments of L3-4 and L4-5 at 4 and 24 weeks after operation. RESULTS: In the experimental segments, the bone sheets were located in the anatomical site of vertebral plate, and no lumbar spinal stenosis or compression of the dura was observed. The bone sheets were absorbed gradually and fused well with the regenerated vertebral plate. While in the control segments, the regeneration of vertebral plate was not completed yet, the scar was inserted into the spinal canal, compressing the dura and the spinal cord, and the epidural area almost disappeared. Compared with the control segments, the dura adhesion degree in the experimental regenerated segments was much milder (P less than 0.01), the internal volume of the vertebral canal had no obvious change and the shape of the dura sack remained well without obvious compression. CONCLUSIONS: Freeze-drying and radiation-sterilized allogeneic bone sheets are ideal materials for extradural laminoplasty due to their good biocompatibility, biomechanical characteristics and osteogenic ability. They can effectively reduce formation of post-laminectomy scars, prevent recurrence of post-laminectomy spinal stenosis, and induce regeneration of vertebral plates.

Ultrasound-guided spinal fracture repositioning, ligamentotaxis, and remodeling after thoracolumbar burst fractures.

STUDY DESIGN: Computed tomography aided evaluation of spinal decompression by ultrasound-guided spinal fracture repositioning, ligamentotaxis, and remodeling after thoracolumbar burst fractures. OBJECTIVES: To determine the necessity of spinal canal widening by ultrasound-guided fracture repositioning for fractures with and without neurologic deficit. SUMMARY OF BACKGROUND DATA: Ultrasound-guided spinal fracture repositioning is an alternative new approach. Reports have varied concerning ligamentotaxis and remodeling. METHODS: Computed tomography aided planimetry of the spinal canal (64 consecutive burst fractures) and neurologic evaluation by Frankel grades. RESULTS: Ultrasound-guided spinal fracture repositioning (n = 37) reduced the stenosis of the spinal canal area from 45% before surgery to 20% after surgery of the estimated original area. Fifteen patients had a primary neurologic deficit, which improved markedly in 11 cases after treatment. Patients with neurologic symptoms had a greater preoperative spinal stenosis than those without. No correlation was seen between the degree of pretreatment spinal stenosis, fracture type, and severity of the neurologic deficit. Ligamentotaxis (n = 27) reduced the stenosis from 30% before surgery to 18% after surgery and remodeling (n = 11) from 25% after surgery to 13% after metal removal. CONCLUSION: Ultrasound-guided fracture repositioning is an efficient method for spinal canal decompression of burst fractures with neurologic symptoms. The marked degree of widening of the spinal canal due to the effects of ligamentotaxis and remodeling may render the reposition of retropulsed fragments unnecessary in cases of fractures without a neurologic deficit.

[Adjacent segment disease after spine fusion and instrumentation].

Spinal instrumentation is a common method for the treatment of spinal disorders, but it can lead to the changes of spine biomechanics. Because of the stress changes, accelerated degeneration of the adjacent segment may occur as time goes by, namely adjacent segment disease. The accelerated degeneration can lead to secondary spinal stenosis, articulated joint degeneration, acquired spondylolisthesis, and spine instability, and some patients may have to receive surgery again. In recent years, the researchers gradually recognized the importance of this disease, and began to investigate its pathogenesis and management.

Pathogenesis, presentation, and treatment of lumbar spinal stenosis associated with coronal or sagittal spinal deformities.

Sagittal- or coronal-plane deformity considerably complicates the diagnosis and treatment of lumbar spinal stenosis. Although decompressive laminectomy remains the standard operative treatment for uncomplicated lumbar spinal stenosis, the management of stenosis with concurrent deformity may require osteotomy, laminectomy, and spinal fusion with or without instrumentation. Broadly stated, the surgery-related goals in complex stenosis are neural decompression and a well-balanced sagittal and coronal fusion. Deformities that may present with concurrent stenosis are scoliosis, spondylolisthesis, and flatback deformity. The presentation and management of lumbar spinal stenosis associated with concurrent coronal or sagittal deformities depends on the type and extent of deformity as well as its impact on neural compression. Generally, clinical outcomes in complex stenosis are optimized by decompression combined with spinal fusion. The need for instrumentation is clear in cases of significant scoliosis or flatback deformity but is controversial in spondylolisthesis. With appropriate selection of technique for deformity correction, a surgeon may profoundly improve pain, quality of life, and functional capacity. The decision to undertake surgery entails weighing risk factors such as age, comorbidities, and preoperative functional status against potential benefits of improved neurological function, decreased pain, and reduced risk of disease progression. The purpose of this paper is to review the pathogenesis, presentation, and treatment of lumbar spinal stenosis complicated by scoliosis, spondylolisthesis, or flatback deformity. Specific attention is paid to surgery-related goals, decision making, techniques, and outcomes.

Trauma-induced myelopathy in patients with ossification of the posterior longitudinal ligament.

OBJECT: In these prospective and retrospective studies the authors evaluated trauma-induced myelopathy in patients with ossification of the posterior longitudinal ligament (OPLL) to determine the effectiveness of preventive surgery for this disease. METHODS: The authors studied 552 patients with cervical OPLL, including 184 with myelopathy at the time of initial consultation and 368 patients without myelopathy at that time. In the former group of 184 patients retrospective analysis was performed using an interview survey to ascertain the relationship between onset of myelopathy and trauma. In the latter group of 368 patients prospective examination was conducted by assessing radiographic findings and noting changes in clinical symptoms apparent during regular physical examination. The follow-up period ranged from 10 to 32 years (mean 19.6 years). In the retrospective investigation, 24 patients (13%) identified cervical trauma as the trigger of their myelopathy. In the prospective investigation, 70% of patients did not develop myelopathy over a follow-up period greater than 20 years (determined using the Kaplan-Meier method). Of the 368 patients without myelopathy at the time of initial consultation, only six patients (2%) subsequently developed trauma-induced myelopathy. Types of ossification in patients who developed trauma-induced myelopathy were primarily a mixed type. All patients in whom stenosis affected 60% or greater of the spinal canal developed myelopathy regardless of a history of trauma. CONCLUSIONS: Preventive surgery prior to onset of myelopathy is unnecessary in most patients with OPLL.

Comparison of two types of surgery for thoraco-lumbar burst fractures: combined anterior and posterior stabilisation vs. posterior instrumentation only.

This retrospective study compares clinical outcome following two different types of surgery for thoracolumbar burst fractures. Forty-six patients with thoracolumbar burst fractures causing encroachment of the spinal canal greater than 50% were operated on within 30 days performing either: combined anterior decompression and stabilisation and posterior stabilisation (Group 1) or posterior distraction and stabilisation using pedicle instrumentation (AO internal fixator) (Group 2). We evaluated: neurological status (Frankel Grade), spinal deformities, residual pain, and complications. The average follow-up was 6 years. There were no significant differences between the patients in both groups concerning age, sex, cause of injury and the presence of other severe injuries. Neurological dysfunction was present in 39% of all cases. Bony union occurred in all patients. Loss of reduction greater than 5 degrees and instrumentation failure occurred significantly more often in Group 2 compared to Group 1, but the kyphosis angle at late follow-up did not differ between groups, due to some degree of overcorrection initially after surgery in Group 2. The clinical outcome was similar in both groups, and all but one patient with neurological deficits improved by at least one Frankel grade. Indirect decompression of the spinal canal by posterior distraction and short-segment stabilisation with AO internal fixator is considered appropriate treatment for the majority of unstable thoracolumbar burst fractures. This is a less extensive surgical procedure than a combined anterior and posterior approach.

+Gz associated stenosis of the cervical spinal canal in fighter pilots.

Previous magnetic resonance imaging (MRI) studies have shown that repeated exposure to +Gz forces can cause premature degenerative changes of the cervical spine (i.e. a work-related disease). This paper reports on two clinical cases of +Gz-associated degenerative cervical spinal stenosis caused by dorsal osteophytes in fighter pilots. Conventional x-rays and MRI were used to demonstrate narrowing of the cervical spinal canal. The first case was complicated by a C6-7 intervertebral disk prolapse and a congenitally narrow spinal canal. The second case involved progressive degenerative spinal stenosis in the C5-6 disk space which required surgery. The findings in this case were confirmed by surgery which showed posterior osteophytes and thickened ligaments compressing the cervical medulla. These two cases suggest that +Gz forces can cause degenerative spinal stenosis of the cervical spine. Flight safety may be jeopardized if symptoms and signs of medullar compression occur during high +Gz stress. It is recommended that student fighter pilots undergo conventional x-rays and MRI studies in order to screen out and reject candidates with a congenitally narrow spinal canal. These examination methods might be useful in fighter pilots' periodic medical check-ups in order to reveal acquired degenerative spinal stenosis.

B-scan ultrasonic measurement of the lumbar spinal canal as a predictor of industrial back pain complaints and extended work loss.

B-scan ultrasonic measurements of lumbar spinal canal diameter were examined as predictors of industrial back pain complaints and extended work loss. Baseline data were collected on 3,020 Washington State aircraft manufacturing workers, and over a mean 3.7-year follow-up period 352 subjects reported industrial back pain complaints. Mean canal measurements of subjects with industrial back pain complaints were smaller at all spinal levels than in subjects without complaints. The mean differences between the groups, however, were extremely small (0.07 mm to 0.51 mm), and not all levels were statistically significant. The relative risk for an L5-S1 measurement 2 standard deviations below the mean was 1.4, yet the measurement explained less than 1% of the uncertainty in predicting complaints. No association was found between canal measurements and claims with extended work loss of greater than one month. The imprecision of the measurements and poor predictive ability indicate that B-scan ultrasonography, as used in this study, is of dubious screening value.