Cervical Spinal Levels Research Articles

The Mandibular Angle as a Landmark for Identification of Cervical Spinal Level

Retrospective radiographic review. To determine the utility of the mandibular angle as a landmark for identification of cervical spinal level. Improper localization of the skin incision during anterior cervical spine surgery may lead to increased technical difficulty of the surgery. Although the use of traditional palpable anterior neck landmarks (hyoid bone, cricoid cartilage, thyroid cartilage, and carotid tubercle) help identify appropriate spinal levels, their reliability has not been validated in actual surgeries. We hypothesize that the angle of the mandible (AM) is a consistently palpable landmark, and that the mandible can be used to accurately template the distance to subaxial cervical levels using preoperative radiographs. As a pilot study, we prospectively evaluated 30 consecutive patients who underwent anterior cervical diskectomy and fusion to assess the interobserver accuracy of palpating the mandibular angle, hyoid, carotid tubercle, and thyroid and cricoid cartilages. In a second set of 26 consecutive patients undergoing anterior cervical diskectomy and fusion, we then retrospectively reviewed standing preoperative lateral plain radiographs of the cervical spine, in addition to supine lateral cervical spine radiographs taken at the time of surgery, to assess: (1) the position of the AM relative to the corresponding cervical spinal level, and (2) whether or not the position of the AM relative to the subaxial cervical levels is different on preoperative standing films and intraoperative supine films. In these same 26 patients, we also measured the vertical distance between the AM and the location of each subaxial intervertebral disc space. These measurements were repeated for the hyoid bone as a control for each patient. The interobserver accuracy was 100% between observers for identifying the AM, hyoid bone, thyroid cartilage, and cricothyroid membrane, and 93% for carotid tubercle. The frequency with which anterior neck landmarks were palpable by the surgeon and assisting senior residents was as follows: AM (100%), hyoid bone (83%), thyroid cartilage and cricothyroid membrane (93%), and carotid tubercle (Surgeon: 63%, Resident: 57%, P = 0.79). There was 100% correlation between the position of the mandibular angle in the preoperative standing lateral radiograph and the intraoperative supine lateral radiograph, compared with 65% with the hyoid bone. The distances between the AM or hyoid to each disc space did not vary significantly between preoperative and intraoperative radiographs (P > 0.05). The mandibular angle was shown to be the most consistently palpable landmark. Further, the distance from the mandible, measured on preoperative plain lateral cervical spine radiographs, is an accurate template to determine cervical spine levels during anterior cervical spine surgery.

Physical Effects of Ejection on the Head-Neck Complex: Demonstration of a Cadaver Model

Vertebral fracture is the most common severe injury during high-speed pilot ejection. However, the loading paradigm experienced by pilots may also lead to soft-tissue spinal injuries that are more difficult to quantify and can lead to long-term deficits. This manuscript describes a new experimental protocol to simulate the effects of pilot ejection on the tissues of the head-neck complex. The model permits precise control of head-neck complex initial positioning, detailed analysis of head and spinal kinematics and upper and lower neck loads, and the ability to thoroughly investigate and identify soft-tissue injuries through upper and lower neck injury criteria, radiography, manual palpation, and cryomicrotomy. For the current test, peak acceleration of +14.8 Gz was similar to actual ejection events and duration of the acceleration pulse was approximately 100 ms. The specimen was oriented in flexion prior to initiation of inferior-to-superiorly directed acceleration. Subfailure ligamentum flavum injuries were sustained at the C4-C5 and C5-C6 cervical spinal levels and identified by increased segmental motions during the simulated ejection, increased laxity following testing, and cryomicrotomy. Upper and lower neck injury criteria did not predict these soft-tissue injuries. This experimental model can be used for detailed analysis of the effects of gender, head-neck orientation, helmet instrumentation, and acceleration pulse characteristics on cervical spine injury potential during pilot ejection events.

The Assessment of Cervical Foramina With Oblique Radiographs: The Effect of Film Angle on Foraminal Area

Radiographic evaluation of cadaveric cervical spine specimens. Assess reliability and reproducibility of foraminal dimensions obtained from cervical radiographs of varying obliquity and determine optimal angles for visualizing foramina at each cervical spine level. Oblique radiographs may be considered to assess cervical foraminal dimensions and are generally obtained 45 degrees from the anteroposterior (AP) orientation. Previous reports have suggested that foraminal area observed on these radiographs may be influenced by changes in obliquity so that certain film angles may be better suited for accurately assessing foramen size, depending on which level is being evaluated. Radiographs of 4 human cadaveric cervical spines were obtained at 5-degree increments from 20 to 70 degrees relative to AP orientation, using both left and right sides of each specimen. Foraminal area was estimated by measuring height and width of each foramen and also with a freehand area measurement tool. Reliabilities of both methods were calculated. At each level, foraminal area was plotted against film angle and quadratic best-fit curves were used to determine the maximum area observed and the optimal angle of obliquity for assessment. Assessment of foraminal area using the height and width values was associated with good interobserver reliability, whereas the freehand method exhibited excellent reliability. The optimal film angles for calculating foraminal area increased from 46.3 degrees for C2-C3 to 56.1 degrees for C7-T1. The ideal film angle that minimized the overall error of measurement across the entire cervical spine was estimated to be 52.4 degrees. Optimal angles for visualizing lower cervical foramina are larger than those for upper cervical spine. To minimize overall loss of foraminal area throughout the entire cervical spine, oblique cervical radiographs should be obtained at an angle of approximately 52 degrees from the AP orientation.

The Relationship between Spinal Stenosis and Neurological Outcome in Traumatic Cervical Spine Injury: An Analysis using Pavlov's Ratio, Spinal Cord Area, and Spinal Canal Area

BackgroundThis study examined the relationship between four radiological parameters (Pavlov's ratio, sagittal diameter, spinal cord area, and spinal canal area) in patients with a traumatic cervical spine injury, as well as the correlation between these parameters and the neurological outcome.MethodsA total of 212 cervical spinal levels in 53 patients with a distractive-extension injury were examined. The following four parameters were measured: Pavlov's ratio on the plain lateral radiographs, the sagittal diameter, the spinal cord area, and the spinal canal area on the MRI scans. The Pearson correlation coefficients between the parameters at each level and between the levels of each parameter were evaluated. The correlation between the radiological parameters and the spinal cord injury status classified into four categories, A (complete), B (incomplete), C (radiculopathy), and D (normal) was assessed.ResultsThe mean Pavlov's ratio, sagittal diameter, spinal cord area and spinal canal area was 0.84, 12.9 mm, 82.8 mm2 and 236.8 mm2, respectively. An examination of the correlation between the radiological spinal stenosis and clinical spinal cord injury revealed an increase in the values of the four radiological parameters from cohorts A to D. Pavlov's ratio was the only parameter showing statistically significant correlation with the clinical status (p = 0.006).ConclusionsThere was a correlation between the underlying spinal stenosis and the development of neurological impairment after a traumatic cervical spine injury. In addition, it is believed that Pavlov's ratio can be used to help determine and predict the neurological outcome.

Importance of contouring the cervical spine levels in initial intensity-modulated radiation therapy radiation for head and neck cancers: Implications for re-irradiation

To evaluate the maximum differential cervical spinal (C-spine) cord dose in intensity-modulated radiation therapy (IMRT) plans of patients undergoing radiotherapy for treatment of head and neck cancer. The C-spine of ten head and neck cancer patients that were planned using IMRT and each cervical vertebral body and the right and left sides was contoured by splitting the cord in the center. Dose-volume histograms (DVH) and maximum point doses were obtained for each contour and compared. The dose to the cord varied with the location of the primary tumor but such variation was not consistently seen. This report provides information that is critical for planning reirradiation treatments. We recommend that contouring of the C-spine cord with IMRT should include outlining of each cervical cord level and identification of the right and the left sides of the cord on each plan.

Stabilization of subaxial cervical spines by lateral mass screw fixation with modified Magerl's technique

Background There are various techniques in lateral mass screw placement in the cervical spine currently available, including the Roy-Camille, Magerl, Anderson, and An techniques. Each has different entrance points and trajectories for screw insertion, and some even have different methods for different level of the subaxial cervical spine. The potential risk of vascular and neurologic injury varies with different techniques and different levels of the cervical spine. We proposed a modified technique with a universal method of screw placement suitable for stabilization of every level of the subaxial cervical spines, from C3 to C7. We have applied this modified technique on a large series of patients and obtained satisfactory results. Methods A retrospective study was conducted of the charts, records, and clinical follow-up of 115 patients who received internal fixation with lateral mass screws and rods in the Department of Neurosurgery of Taipei Veterans General Hospital (Taipei, Taiwan) from 2004 to 2006. All patients received lateral mass screw placement in various levels of the subaxial cervical spines. The clinical and radiologic follow-up were carefully evaluated and analyzed. Results All 115 patients with different pathological situations requiring stabilization received instrumentations with polyaxial screws and rod systems, in which 673 screws in total were used in various levels of the cervical spine between C3 and C7: 129 screws in C3, 115 in C4, 193 in C5, 101 in C6, and 135 in C7. The most often used screw length was 16 mm (385/673, 57%). Good bony fusion was observed in all patients except 1 (99.1%). The mean follow-up period was 14 months (4-35 months). No neurologic or vascular injury was noted clinically. Follow-up radiologic examinations found that the screw placements were well positioned. Conclusions Based on our experience, lateral mass fixation of subaxial cervical spines with our modified technique is safe and effective. This technique of lateral mass screw placement yielded good fusion rate with very few complications and can be considered as a good alternative compared to techniques previously reported by other authors. It can eliminate the need of different techniques for different level to be fixed. In the selected cases, skipped level fixation with this technique is also satisfactory.

Conventional versus Digital X-rays for Intraoperative Cervical Spine Level Localization

Conventional versus Digital X-rays for Intraoperative Cervical Spine Level Localization

Long-term Biomechanical Stability and Clinical Improvement After Extended Multilevel Corpectomy and Circumferential Reconstruction of the Cervical Spine Using Titanium Mesh Cages

Retrospective review of clinical case series. We present our experience with extended (> or =3 levels) anterior cervical corpectomy (EACC) and reconstruction. Multilevel cervical corpectomy has traditionally been associated with increased graft-related complications and worse clinical outcomes compared with single-level procedures. Data specifically regarding corpectomies across 3 or more levels remains limited. Retrospective review of data on 20 patients who underwent anterior cervical corpectomies with titanium mesh cage reconstruction and supplemental posterolateral fixation across 3 or more levels of the cervical spine. Anteroposterior/lateral plain films were used to determine sagittal balance and cage subsidence. Fusion was defined as the lack of motion on flexion-extension radiographs. Patients underwent preoperative and postoperative clinical assessment using visual analog scores and Nurick grading. Surgery was performed for spondylotic myelopathy in 15 patients, osteomyelitis in 4, and fracture in 1. Corpectomies were performed across an average of 3.4 levels. Average follow-up was 33 months. Local autograft was used in all cases except osteomyelitis, where allograft was used instead. Sagittal balance was improved or maintained in all patients and was not related to number of corpectomy levels. An average of 30.2 degrees of kyphosis correction was achieved in 9 patients. All patients demonstrated radiographic evidence of fusion without significant cage subsidence and no cases of instrumentation failure. Improvement in pain and functional scores occurred in all cases. Circumferential reconstruction using titanium mesh cages after EACC can provide appropriate, biomechanically stable fixation and allows for significant correction of preexisting kyphosis. Supplemental posterior instrumentation may limit delayed cage subsidence and loss of sagittal balance after this procedure. EACC and circumferential reconstruction seems to be an effective treatment for symptomatic degenerative, traumatic, or infectious pathology involving 3 or more levels of the anterior cervical spine.

Normative Segment-Specific Axial and Coronal Angulation Corridors of Subaxial Cervical Column in Axial Rotation

In contrast to clinical studies wherein loading magnitudes are indeterminate, experiments permit controlled and quantifiable moment applications, record kinematics in multiple planes, and allow derivation of moment-angulation corridors. Axial and coronal moment-angulation corridors were determined at every level of the subaxial cervical spine, expressed as logarithmic functions, and level-specificity of range of motion and neutral zones were evaluated. segmental primary axial and coupled coronal motions do not vary by level. Although it is known that cervical spine responses are coupled, segment-specific corridors of axial and coronal kinematics under axial twisting moments from healthy normal spines are not reported. Ten human cadaver columns (23-44 years, mean: 34 +/- 6.8) were fixed at the ends and targets were inserted to each vertebra to obtain kinematics in axial and coronal planes. The columns were subjected to pure axial twisting moments. Range of motion and neutral zone for primary-axial and coupled-coronal rotation components were determined at each spinal level. Data were analyzed using factorial analysis of variance. Moment-rotation angulations were expressed using logarithmic functions, and mean +/-1 standard deviation corridors were derived at each level for both components. Moment-angulations responses were nonlinear. Each segmental curve for both components was well represented by a logarithmic function (r2 > 0.95). Factorial analysis of variance indicated that the biomechanical metrics are spinal level-specific (P < 0.05). Axial and coronal angulations of cervical spinal columns show statistically different level-specific responses. The presentation of moment-angulation corridors for both metrics forms a dataset for the normal population. These segment-specific nonlinear corridors may help clinicians assess dysfunction or instability. These data will assist mathematical models of the spine in improved validation and lead to efficacious design of stabilizing systems.

Airway Changes After Anterior Cervical Discectomy and Fusion

Anterior cervical discectomy and fusion (ACDF) is a common procedure for radicular and spondylotic disease of the cervical spine. Radiographs are routinely used to evaluate complications in the postoperative ACDF patient, especially airway compromise. Our purpose was to establish baseline data on the amount of change that can be expected in the prevertebral soft tissues after this procedure in the uncomplicated asymptomatic (no airway compromise) 1 or 2-level ACDF patient. Our hypothesis was that the upper cervical spinal levels (C2-C4) would experience greater degrees of swelling than the lower cervical spine (C5-C7). To date no published data exist in the English literature upon which to judge symptomatic patients (experiencing postoperative airway distress) radiographically. We prospectively evaluated preoperative and postoperative x-rays of 32 patients undergoing ACDF for radicular or spondylotic cervical pathology. Measurements were taken from the anterior body of the cervical spine to the posterior aspect of the airway. The postoperative differences for each level from C2 to T1 were calculated. We found that the greatest level of swelling or change in the prevertebral soft tissues occurred at the mid-body of C4 in uncomplicated cases with an average change of 10.7 mm. No patients measured greater than 25 mm at C4. As we predicted, the greatest edema was noted in the upper cervical spine. Studies need to be performed to compare the radiographic data of symptomatic patients with the baseline data we have collected.

Development of Spontaneous Intracranial Hypotension Concurrent With Grade IV Mobilization of the Cervical and Thoracic Spine: A Case Report

Donovan JS, Kerber CW, Donovan WH, Marshall LF. Development of spontaneous intracranial hypotension concurrent with grade IV mobilization of the cervical and thoracic spine: a case report. Spontaneous intracranial hypotension (SIH) has been clinically defined as the development of severe orthostatic headaches caused by an acute cerebrospinal fluid (CSF) leak. Typically, intracranial hypotension occurs as a complication of lumbar puncture, but recent reports have identified cases caused by minor trauma. We report a case of SIH secondary to a dural tear caused by a cervical and thoracic spine mobilization. A 32-year-old woman with SIH presented with severe positional headaches with associated hearing loss and C6-8 nerve root distribution weakness. CSF opening pressure was less than 5cmH 2O and showed no abnormalities in white blood cell count. Cranial, cervical, and thoracic magnetic resonance imaging revealed epidural and subdural collections of CSF with associated meningeal enhancement. Repeated computed tomography myelograms localized the leak to multiple levels of the lower cervical and upper thoracic spine. A conservative management approach of bedrest and increased caffeine intake had no effect on the dural tear. The headache, hearing loss, and arm symptoms resolved completely after 2 epidural blood patches were performed. Practitioners performing manual therapy should be aware of this rare, yet potential complication of spinal mobilizations and manipulations.

Time of early death after cervical spinal cord injury

To investigate the distribution of time of early death in the patients with cervical spinal cord injury (CSCI). The clinical data of 63 CECI patients, including demographics, mechanism of injury, cervical spinal cord injury level and severity, associated injury, radiographs, management, and the causes of death, the time from injury to hospitalization and the time from injury to death were retrospectively analyzed so as to detect the time and cause of early death. The 63 CDCI patients died in early stage. 27 of the 63 patients (42.8%) died within a week after CSCI; 43 patients (68.3%) died within two weeks after CSCI, 57 patients (90.5%) died within four weeks after CSCI, and 6 patients (9.5%) died after four weeks after CSCI. The peak time of death is a week after CSCI. The major time of death is two weeks after CSCI. 90.5% cases died within four weeks. Respiratory failure is the leading cause of early death in patients with CSCI.

Cervical intrathecal analgesia for head and neck/upper limb cancer pain: six case reports

We describe six cases of head and neck or upper limb cancer palliative care patients with refractory pain, treated with an intrathecal catheter placed at cervical or upper thoracic spinal levels with a non-implanted, externalized and tunnelled delivery system. In these cases, this system was safe and effective. Palliative Medicine 2007; 21 : 543—545

Cervical Spondylolysis, Radiologic Pointers of Stability and Acute Traumatic as Opposed to Chronic Spondylolysis

Case report and literature review. We report a case of subaxial cervical spondylolysis and review 142 reports of this anomaly in the English language literature to determine the cause, the distribution, the stability, and the prognosis of cervical spondylolysis. Cervical spondylolysis may affect any level of the lower cervical spine with the C6 isthmus being the most commonly affected region (48%). In 40% of cases, there were radiologic features consistent with congenital cervical spondylolysis and in 74% of cases there was a history of acute trauma. The radiographic features of congenital cervical spondylolysis are quite specific and can exclude trauma as a cause for the spondylolysis. Although instability was not commonly assessed, 30% of cases assessed with flexion-extension views were found to be unstable. These included 27 cases of myelopathy of which 26 were attributable to instability. Many treatment modalities have been employed to treat ranging from early mobilization to decompression and fusion. Three patients with radiologic signs of instability and no neurologic deficit were treated conservatively, whereas 1 patient with no neurologic deficit or instability was treated with spinal fusion. We found a direct relationship between spinal instability and the presence of neurologic deficit (P < 0.001). On the basis of this systematic review of case reports of lower cervical spondylolysis, we can recommend that spondylolysis of the lower cervical spine can be treated nonoperatively except in those with radiologically documented cervical instability.

Modified Paramedian Transpedicular Approach and Spinal Reconstruction for Intradural Tumors of the Cervical and Cervicothoracic Spine

Retrospective review of the medical, radiographic, surgical, and postoperative records of patients who underwent resection of multilevel intradural extramedullary spinal cord tumors of the ventral cervical and cervicothoracic spine via a modified paramedian transpedicular approach at the University of California, San Francisco, between 2003 and 2005. To assess the surgical, clinical, and radiographic outcomes of using the modified paramedian transpedicular approach to resect ventral intradural extramedullary spinal cord tumors of the ventral cervical and cervicothoracic spine. A common theme of skull-base surgery for many years has been to remove the bone rather than retract neural elements. In this report, we demonstrate some possible advantages of taking a "spine-base" approach for resecting intradural extramedullary spinal cord tumors of the ventral cervical and cervicothoracic spinal canal, and present our clinical experience. All medical, surgical, and radiologic records were retrospectively reviewed. Clinical outcome was assessed for disability via the Neck Disability Index and for pain via the visual analog scale. Fourteen patients (4 males and 10 females, average age 39.6 years, range 20-62) with intradural extramedullary spinal cord tumors involving multiple levels of the anterior cervical and cervicothoracic spine were identified. All patients presented with pain and/or radiculomyelopathy attributed to a ventral intradural extramedullary spinal cord tumor of the cervical or cervicothoracic spine that was resected via the modified paramedian transpedicular approach with partial dorsal corpectomy and posterior spinal reconstruction. The average follow-up period was 14.6 months (range 5-30). Gross total resection was achieved in all cases, and no patient required additional surgery via an anterior approach for residual tumor. The modified paramedian transpedicular approach with partial dorsal corpectomy we describe here is a variation of traditional thoracic posterolateral transpedicular extracavitary approaches and offers direct access to lesions of the ventral cervicothoracic spinal canal. This approach avoids the morbidity of anterior transcervical, transoral, or transthoracic procedures, while providing a view of the entire ventral cervicothoracic canal, and can be performed safely and effectively in select patients.

Prevalence of Modic Degenerative Marrow Changes in the Cervical Spine

Objective The prevalence and distribution of Modic degenerative marrow changes as seen on magnetic resonance imaging scans have been reported for the lumbar spine, and research suggests that type 1 Modic changes are linked to low back pain. The purpose of this study was to report on the prevalence, types, and distribution of the changes found for the cervical spine. Methods One hundred thirty-three cervical spine T 1-weighted and T 2-weighted sagittal magnetic resonance imaging scans were viewed retrospectively by two radiologists. Data were recorded for patient age, patient sex, and the presence or absence of Modic changes. If Modic changes were present, then the precise vertebral levels of these changes and the specific Modic type were recorded. Descriptive statistics were calculated for the prevalence of Modic changes overall, the prevalence of types 1, 2, and 3 changes, and the prevalence in male vs female patients. The frequency of these changes by spinal level was also determined. Results One hundred eighteen patients met the inclusion criteria. Modic changes were seen in 19 patients (16%), with 4 showing changes in more than one segmental level. The most common Modic change observed was type 1. Type 3 marrow changes were the second most common category to be noted. Only 3 patients had Modic type 2 marrow changes. The most common cervical spinal level to show Modic changes was C5-6. Conclusions Modic degenerative bone marrow changes are observed in the cervical spine, with the C5-6 level being the most commonly involved. Unlike in the lumbar spine in which Modic type 2 changes predominate, type 1 marrow changes were far more common in the cervical spine. Further studies should focus on the clinical relevance of these findings.

Objective assessment of cervical spinal cord injury levels by transcranial magnetic motor-evoked potentials

Background The neurologic examination serves as the optimal method to record the level of spinal cord injury (SCI). However, this test is subject to interexaminer variability. To address this shortcoming, we describe a technique that uses transcranial magnetic motor-evoked potentials (tcMMEPs) and dermatomal somatosensory-evoked potentials (d-SSEPs) to more accurately measure the precise level of SCI. Methods Two groups of subjects were studied: (1) complete cervical SCI (n = 10) and (2) neurologically intact volunteers (n = 10). Two additional patients were evaluated: one with a cervical central spinal cord syndrome and another with a head injury with a suspected cervical SCI. Each subject underwent upper extremity tcMMEPs and d-SSEPs. Results Transcranial magnetic motor-evoked potentials were elicited from all upper limb myotomes (C4-T1, bilaterally) in neurologically intact volunteers (20 sides). The level of injury was determined using tcMMEPs by observing the lowest level of measurable response. The level of injury obtained using tcMMEPs was the same as that determined by neurologic examination in 13 (65%) of the 20 sides. In 7 sides, tcMMEP responses were obtained 1 level lower than that assessed by physical examination. Dermatomal somatosensory-evoked potentials were obtained from all dermatomes of volunteers tested in the laboratory compared with only 5 of the 9 patients with SCI who underwent d-SSEP testing. Conclusion Testing using tcMMEPs provides an objective supplement to the neurologic examination after acute cervical SCI. Dermatomal somatosensory-evoked potentials were of limited value in determining the level of cervical SCI.

Clinical and radiological results following cervical arthroplasty

This was a retrospective study of clinical and radiological results of cervical arthroplasty using the Bryan cervical disc prosthesis to evaluate the efficacy of arthroplasty in clinical applications. A total of 46 patients underwent arthroplasty of a single level using the Bryan disc prosthesis. Clinical outcome was assessed using the visual analogue scale (VAS) and the neck disability index (NDI). All patients were evaluated using preoperative and postoperative static cervical spine radiographs to compare cervical sagittal balance. Dynamic cervical spine radiographs were used to compare movement at the level of the procedure, movement at the adjacent level and movement of the whole cervical spine. With the exception of four patients with aggravated neck pain, the NDI and VAS scores decreased significantly in late follow-up evaluations. The range of movement of the whole cervical spine, the functional segmental unit, and the adjacent segments were preserved after arthroplasty. The sagittal alignment of the cervical spine showed kyphosis after surgery but restored lordosis at a later time. The postulated cause of kyphotic changes include "over-milling" at the dorsal endplate, inappropriate angle of disc insertion, structural absence of lordosis in the Bryan disc, removal of posterior longitudinal ligament, and pre-existing kyphosis. Arthroplasty using the Bryan disc appears to be safe and provided a favorable preliminary clinical and radiological outcome. Postoperative kyphosis can be prevented by understanding the biomechanical properties of the Bryan disc. Future studies will need to address the association between postoperative kyphosis, clinical outcome and adjacent segment disease.

Concepts leading to the definition of the term cervicogenic headache: a historical overview

The idea that headache may originate from a problem at the neck or cervical spine level has fascinated and stimulated researchers for centuries. Contributions and reports seeking to clarify this issue have multiplied in the past 80 or 90 years. Bärtschi–Rochaix reported what seems to have been the first clinical description of cervicogenic headache, but it was not until 1983 that Sjaastad and his school defined diagnostic criteria for this sydrome. The current, revised International Headache Society Classification (ICHD–II) includes the term cervicogenic headache, but the diagnostic criteria it gives differ from those of the International Association for the Study of Pain (IASP), and also from the most recent Cervicogenic Headache International Study Group (CHISG) definition (1998).

Experimental study of the participation of the vertebral endplate in the integration of bone grafts

The surgical technique of anterior vertebral arthrodesis has been modified by the introduction of cages in spinal surgery. The classical technique recommends removal of the vertebral endplate and exposure of bleeding cancellous bone. However, after the observation of cage subsidence during postoperative follow-up, the vertebral endplate is no longer removed, due to its greater mechanical resistance which can prevent cage subsidence. The mechanical characteristics of the vertebral endplate are well known, in contrast to its osteogenic potential, which was investigated in the present experimental study. The study was conducted on mongrel dogs of both sexes, which were submitted to anterior corpectomy at the cervical spine level. A cortico-cancellous bone graft removed from the tibia was used for the reconstruction of the vertebral segment, which was used with osteosynthesis plates. At the site of contact between the surface of the vertebral body and the bone graft, the vertebral endplate was completely removed and cancellous bone was exposed in the inferior vertebra, whereas in the superior vertebra of the arthrodesed vertebral segment only curettage was performed, and the vertebral endplate was preserved, as recommended for cage implantation. Twenty adult dogs of both sexes were divided into four experimental groups according to time of sacrifice (15, 30, 90, and 180 days). The consolidation of the bone graft with the vertebral body was evaluated by histology using hematoxilin-eosin and Gomori trichrome staining. In the interface between the bone graft and the vertebral body surface in which the vertebral endplate was not removed, graft consolidation was not observed in any of the group I animals (sacrificed after 15 days), and was observed in 1/5 animals of group II (30 days), in 2/5 animals of group III (90 days), and in 4/5 animals of group IV (180 days). In the interface between the graft and the vertebral body in which the vertebral endplate was removed, bone-graft consolidation was observed in all animals of all experimental groups (15, 30, 90, and 180 days). Bone-graft consolidation with the surface of the vertebral body was influenced by the removal or maintenance of the vertebral endplate. Due to the importance of this structure in current surgical procedures, this phenomenon deserves to be studied in more detail in order to understand the basic events involved in this process.