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European Spine Journal : Official... Jun 2016The aim of this retrospective study was to evaluate the changes in the vertebral body and spinal canal area in a group of patients who had pedicle screw fixation under...
PURPOSE
The aim of this retrospective study was to evaluate the changes in the vertebral body and spinal canal area in a group of patients who had pedicle screw fixation under age 5 for the treatment of congenital spinal deformity at least 5 year follow-up.
METHODS
11 patients who had been operated due to spinal deformity under age 5 with who had a CT examination at least 5 years after the initial operation were included in the study. All patients underwent hemivertebrectomy and transpedicular fixation procedures at an average age of 3.18 years (range 2-5 years). All had preoperative CT to evaluate the congenital deformities. Measurements were done at the instrumented vertebrae as well as the un-instrumented ones above and below them to evaluate; vertebral body parameters, pedicle parameters and spinal canal area of upper instrumented vertebra (UIV), lower instrumented vertebra (LIV), upper adjacent un-instrumented vertebra and lower adjacent un-instrumented vertebra.
RESULTS
The average follow-up was 7.2 (range 5-12) years. Six of the patients were over age 10 during the final CT examination while 5 were at age 7. Female-to male ratio was 8-3. Measurement of all the parameters in 22 instrumented and 22 non-instrumented segments showed a proportional increase rather than a decrease at each segment. The percentage of canal area growth at UIV and LIV was 21 and 17.5 %, respectively.
CONCLUSION
Pedicle screw instrumentation has no adverse effect on further spinal body, pedicle and canal growth and does not result in iatrogenic spinal canal stenosis.
Topics: Child; Child, Preschool; Female; Follow-Up Studies; Humans; Male; Pedicle Screws; Spinal Canal; Spinal Fusion; Tomography, X-Ray Computed
PubMed: 27001135
DOI: 10.1007/s00586-016-4484-6 -
Spine Nov 2000In vitro measurement of the area of the spinal canal in the rostral and caudal portions of lumbar vertebrae before and after application of a new technique called... (Comparative Study)
Comparative Study
STUDY DESIGN
In vitro measurement of the area of the spinal canal in the rostral and caudal portions of lumbar vertebrae before and after application of a new technique called "inverse laminoplasty."
OBJECTIVES
To quantify the normal area of the spinal canal in the rostral and caudal portions of lumbar vertebrae and the amount of enlargement gained after inverse laminoplasty.
SUMMARY AND BACKGROUND DATA
Other types of laminoplasty have been proven to increase the area of the spinal canal. Inverse laminoplasty has been performed in 10 patients but has not been evaluated in vitro.
METHODS
The transverse and anteroposterior diameter of the spinal canal was measured in 34 vertebrae from seven cadavers using digital calipers. In each vertebra, the laminae and spinous process were removed en bloc using a high-speed drill. The removed piece was inverted and reattached with titanium mini-plates. The area of the spinal canal was again measured and compared with the prelaminoplasty measurements using paired Student's t tests.
RESULTS
The anteroposterior diameter and area of the spinal canal were significantly smaller before surgery in the rostral than in the caudal part of the vertebrae (P <10(-3)). The rostral and caudal areas of the spinal canal increased by 61% and 17%, respectively, after the laminae were inverted (P <10(-3)).
CONCLUSION
Because inverse laminoplasty is simple and increases the area of the spinal canal, it may prove to be a useful surgical technique for the treatment of lumbar spinal stenosis. Further studies are needed to determine whether the technique is biomechanically sound and whether it helps prevent perineural scarring.
Topics: Adult; Aged; Cicatrix; Decompression, Surgical; Humans; In Vitro Techniques; Lumbar Vertebrae; Middle Aged; Peripheral Nerves; Spinal Canal; Spinal Cord Compression; Spinal Stenosis
PubMed: 11064522
DOI: 10.1097/00007632-200011010-00009 -
Spine Jan 1996Prospective evaluation of spinal canal areas in 67 consecutive burst fractures between T12 and L2 treated by reduction and stabilization with a pedicle fixator.
STUDY DESIGN
Prospective evaluation of spinal canal areas in 67 consecutive burst fractures between T12 and L2 treated by reduction and stabilization with a pedicle fixator.
OBJECTIVES
Assessment of the efficacy of "indirect" spinal canal decompression in a large series of burst fractures.
SUMMARY OF BACKGROUND DATA
Up to 50% of burst fractures cause neurologic impairment. Reduction and posterior instrumentation is the most common surgical treatment. This also reduces spinal canal encroachment by indirect decompression. No consensus exists as to the consistency and adequacy of such indirect decompression.
METHODS
Spinal canal areas were measured on preoperative and postoperative computed tomography scans. The degree of encroachment was compared with clinical and radiographic variables for possible correlation.
RESULTS
Spinal canal encroachment was more severe among patients with neurologic deficits than among the neurologically intact. Postoperatively, mean encroachment was reduced from 35% to 12% at T12, from 37% to 17% at L1, and from 52% to 35% at L2. Loss (and postoperative restoration) of anterior vertebral height correlated best with the degree of canal encroachment (and its reduction), especially in Denis Type A burst fractures. In Denis Type B fractures, canal compromise usually was less severe and fragment reduction better in patients older than 40 years of age than in younger patients.
CONCLUSIONS
Indirect decompression in burst fractures averages about half of the preexisting encroachment. Results are usually better at T12 and L1 than at L2. Additional or secondary decompression is rarely indicated if these fractures are treated early and by experienced surgeons. Burst Type B fractures in patients older versus younger than 40 years of age differ in many respects.
Topics: Adult; Aged; Bone Screws; Female; Humans; Male; Middle Aged; Postoperative Period; Prospective Studies; Spinal Canal; Spinal Fractures; Tomography, X-Ray Computed
PubMed: 9122751
DOI: 10.1097/00007632-199601010-00026 -
Spine Mar 1999An evidence-based analysis of published radiologic criteria for assessing spinal canal compromise and cord compression in patients with acute cervical spinal cord injury. (Meta-Analysis)
Meta-Analysis
The optimal radiologic method for assessing spinal canal compromise and cord compression in patients with cervical spinal cord injury. Part I: An evidence-based analysis of the published literature.
STUDY DESIGN
An evidence-based analysis of published radiologic criteria for assessing spinal canal compromise and cord compression in patients with acute cervical spinal cord injury.
OBJECTIVES
This study was conducted to determine whether literature-based guidelines could be established for accurate and objective assessment of spinal canal compromise and spinal cord compression after cervical spinal cord injury.
SUMMARY OF BACKGROUND DATA
Before conducting multicenter trials to determine the efficacy of surgical decompression in cervical spinal cord injury, reliable and objective radiographic criteria to define and quantify spinal cord compression must be established.
METHODS
A computer-based search of the published English, German, and French language literature from 1966 through 1997 was performed using MEDLINE (U.S. National Library of Medicine database) to identify studies in which cervical spinal canal and cord size were radiographically assessed in a quantitative manner. Thirty-seven references were included for critical analysis.
RESULTS
Most studies dealt with degenerative disease, spondylosis, and stenosis; only 13 included patients with acute cervical spinal cord injury. Standard lateral radiographs were the most frequent imaging method used (23 studies). T1- and T2-weighted magnetic resonance imaging were used to assess spinal cord compression in only 7 and 4 studies, respectively. Spinal cord size or compression were not precisely measured in any of the cervical trauma studies. Interobserver or intraobserver reliability of the radiologic measurements was assessed in only 7 (19%) of the 37 studies.
CONCLUSIONS
To date, there are few quantitative, reliable radiologic outcome measures for assessing spinal canal compromise or cord compression in patients with acute cervical spinal cord injury.
Topics: Cervical Vertebrae; Humans; MEDLINE; Radiography; Sensitivity and Specificity; Spinal Canal; Spinal Cord Compression; Spinal Cord Injuries
PubMed: 10101828
DOI: 10.1097/00007632-199903150-00022 -
European Spine Journal : Official... Jan 2024The objective of this study was to investigate the optimal entry point and pedicle camber angle for L5 pedicle screws of different canal types.
PURPOSE
The objective of this study was to investigate the optimal entry point and pedicle camber angle for L5 pedicle screws of different canal types.
METHODS
CT imaging data were processed by Mimics for simulated pedicle screw placement, and PD (Pedicle diameter), PCA (Pedicle camber angle), LD (Longitudinal distance), TD (Transverse distance), and PBG (Pedicle screw breach grade) were measured. Then they were divided into the Round group and Trefoil group according to the type of spinal canal. When comparing PD, PCA, LD, TD, and PBG, the two sides of the pedicle were compared separately, so they were first divided into the round-type pedicle group and the trefoil-type pedicle group.
RESULTS
In the round-type pedicle group (n = 134) and the trefoil-type pedicle group (n = 264), there was no significant difference in PD and LD, but there was a significant difference in PCA between the two groups (t = - 4.072, P < 0.05). A statistically significant difference in the distance of the Magerl point relative to the optimal entry point (t = - 3.792, P < 0.05), and the distance of the Magerl point relative to the optimal entry point was greater in the trefoil-type pedicle group than in the round-type pedicle group.
CONCLUSION
The optimal entry point for L5 is more outward than the Magerl point, and the Trefoil spinal canal L5 is more outwardly oriented than the Round spinal canal L5, with a greater angle of abduction during pedicle screw placement.
Topics: Humans; Pedicle Screws; Retrospective Studies; Spinal Fusion; Spinal Canal; Tomography, X-Ray Computed
PubMed: 37659047
DOI: 10.1007/s00586-023-07904-0 -
Spine Jan 2004A computer-aided design analysis. (Comparative Study)
Comparative Study
STUDY DESIGN
A computer-aided design analysis.
OBJECTIVES
To introduce the concept of volumetric spinal canal intrusion and report the relative intrusion volumes for thoracic pedicle screws compared to thoracic laminar and pedicle hooks.
SUMMARY OF BACKGROUND DATA
Thoracic pedicle screws are being used more frequently; however, there is concern about neurologic risk from medial misplacement. The accepted alternative to screws is hooks. Laminar and pedicle hooks also have significant obligatory spinal canal intrusion. To date, there have been no comparison studies.
METHODS
Volumetric analysis of canal intrusion of pedicle screws and hooks was performed by computer-aided design CAM. All implants were of a single product line by a single manufacturer (CD Horizon M8, Medtronic Sofamor Danek). Intrusion of pedicle screws with medial positioning was analyzed in 0.5-mm increments, including a calculation of the "screw shadow," representing additional space not available for the spinal cord between screw threads and lateral to a medially positioned screw with intrusion greater than the screw radius. The length of screw intrusion was determined from postoperative CT scans in patients with thoracic pedicle screw instrumentation. All hook styles were analyzed. The volume of the footplate in line with the dorsal surface of the footplate was considered the intruding volume for laminar hooks, with increasing offset in 0.25-mm increments to represent imperfect fit. Half of the volume of the footplate was considered to be the intruding volume for pedicle hooks since a properly positioned pedicle hook straddles the pedicle.
RESULTS
Volumetric intrusion for a 4.5-mm screw ranged from 2.2 mm3 (0.5 mm medial perforation) to 83.4 mm3 (3.0 mm perforation). For a 5.5-mm screw, intrusion volume range was from 1.3 mm3 to 83.2 mm3. Accounting for the "screw shadow," the volumetric intrusion was 9.83 mm3 to 116.3 mm3 and 10.88 mm3 to 134.89 mm3, respectively. Hook volumetric intrusion ranged from 21.15 mm3 for a pediatric narrow-blade ramped pedicle hook to 113.9 mm3 for a wide-blade laminar hook with 1.0 mm of step-off.
CONCLUSIONS
A 4.5-mm or 5.5-mm thoracic pedicle screw must have a medial perforation of >or=1.5 mm to have the same volumetric spinal canal intrusion as a pediatric narrow-blade pedicle hook, the smallest hook footplate. Further, the medial violation must be >3 mm to approach the same volumetric intrusion as the largest hook. Accounting for the "screw shadow," a thoracic pedicle screw must have a medial perforation of >2 mm to approach the same intrusion volume as a standard pedicle hook. In the absence of direct neural injury, this explains the clinical finding of medial perforation of up to 4 mm without neurologic compromise.
Topics: Animals; Bone Screws; Humans; Materials Testing; Orthopedic Fixation Devices; Orthopedic Procedures; Radiography; Software; Spinal Canal; Thoracic Vertebrae
PubMed: 14699278
DOI: 10.1097/01.BRS.0000105525.06564.56 -
Bulletin (Hospital For Joint Diseases... 1996The exact size of the bony cervical spinal canal and the vertebral body was measured in 368 cadaveric adult male vertebrae. A comparison of radiographic and direct...
The exact size of the bony cervical spinal canal and the vertebral body was measured in 368 cadaveric adult male vertebrae. A comparison of radiographic and direct measurements was also undertaken. The mean sagittal diameter of the spinal canal for C3-C7 was close to 14 mm (14.07 +/- 1.63 mm; N = 272). The mean ratio of the sagittal canal diameter to the vertebral body diameter (canal to body ratio) was 86.68 +/- 13.70 mm. Thirty-one percent of subaxial vertebrae would be diagnosed as having spinal stenosis if a canal to body ratio of less than 80% was considered abnormal. Measurements from plain radiographs overestimate the canal diameter. The average diameter for the lower cervical spinal canal is about 14 mm. The canal to body ratio is independent of radiographic magnification, but may produce misleading results.
Topics: Adult; Aged; Aged, 80 and over; Cadaver; Cervical Vertebrae; Confidence Intervals; Humans; Male; Middle Aged; Radiography; Sensitivity and Specificity; Spinal Canal; Spinal Stenosis
PubMed: 8879738
DOI: No ID Found -
The Journal of Veterinary Medical... Oct 2020A 17-year-old mongrel dog and 12-year-old Shiba Inu dog presented with ataxia and paresis of the pelvic limbs, respectively. Gas accumulation within the spinal canal...
A 17-year-old mongrel dog and 12-year-old Shiba Inu dog presented with ataxia and paresis of the pelvic limbs, respectively. Gas accumulation within the spinal canal adjacent to the herniated disc was suspected in both cases. Since the gas remained accumulated for a prolonged period, hemilaminectomy was performed to decompress the spinal cord. The bulged external lamina of the dura matter was removed and histopathologically examined. Granulomatous inflammation and hyperplasia of fibrous connective tissues was noted, suggesting that the gas was encapsulated and the fibrous nodules made reabsorption difficult. Clinical signs resolved post-surgery. This is the first report describing histopathological features of pneumorrhachis in dogs. The accumulated gas was successfully removed by surgery. Postoperative course remained uneventful in both cases.
Topics: Animals; Dog Diseases; Dogs; Intervertebral Disc Degeneration; Intervertebral Disc Displacement; Laminectomy; Pneumorrhachis; Spinal Canal
PubMed: 32779622
DOI: 10.1292/jvms.20-0052 -
British Journal of Neurosurgery Feb 2020The anomalous anatomical arrangement of the thoracic spinal nerve roots within the spinal canal can complicate the surgical treatment of several pathologies. The aim of...
The anomalous anatomical arrangement of the thoracic spinal nerve roots within the spinal canal can complicate the surgical treatment of several pathologies. The aim of this work was to reveal intraspinal anatomical variations of the thoracic spinal nerve roots. Anatomical study on 43 cadavers with a mean age of 53.7. After opening the spinal canal and dural sac, intradural and extradural anomalies of the thoracic spinal nerve roots were documented. Extradural communicating branches were excised, histologically processed and examined for the presence of nervous tissue. We found 14 cases (32.6%) of intraspinal thoracic nerve root variations: intradural in 8 cases (18.6%), intradural communicating branches in 3 cases (6.97%), extradural anatomical variations occurred 6 cases (13.95%), 2 cases (4.65%) had extradural communicating branches between the nerve roots, 1 case had simultaneous occurrence of intradural and extradural communications (0.23%). All the results are differentiated according to the plexus type. In macroscopic extradural thoracic communicating branch had no nervous tissue on microscopy. This study describes intraspinal anatomical variations of thoracic spinal nerve roots. Knowledge of these variables should help prevent the failure of several medical procedures.
Topics: Adult; Aged; Cadaver; Dura Mater; Female; Humans; Male; Middle Aged; Spinal Canal; Spinal Nerve Roots; Thoracic Vertebrae
PubMed: 31668095
DOI: 10.1080/02688697.2019.1681360 -
Anaesthesiology Intensive Therapy 2012Pneumorrhachis (PR) means the presence of air in the spinal canal; it is an exceptional, but important radiographic finding, which may be associated with different...
BACKGROUND
Pneumorrhachis (PR) means the presence of air in the spinal canal; it is an exceptional, but important radiographic finding, which may be associated with different aetiologies and pathways of air entry into the spinal canal.
CASE REPORT
An 18-year-old male was admitted to hospital after a road traffic accident. He was conscious, with several abrasions and subcutaneous haematoma and emphysema on the left side, but no pneumothorax. Ultrasound of the abdomen showed a grade 2 splenic rupture with minimal bleeding. CT revealed no fractures but the presence of air in the spinal canal. The patient was placed on conservative treatment and discharged home without any complications or sequelae.
DISCUSSION AND CONCLUSION
PR can be epidural or subdural, iatrogenic or traumatic. It is usually asymptomatic, but can be also associated with marked morbidity, especially when it is subdural in the cervical region. It can be regarded as a predictor of the severity of head injury. Pneumorrhachis does not usually require surgical intervention.
Topics: Accidents, Traffic; Adolescent; Humans; Male; Pneumorrhachis; Spinal Canal; Tomography, X-Ray Computed; Trauma Severity Indices
PubMed: 23801509
DOI: No ID Found