A prospective randomized multicenter clinical evaluation of an anterior cervical fusion cage

STUDY DESIGN

A prospective, concurrently controlled, randomized, multicenter trial of an anterior Bagby and Kuslich cervical fusion cage (BAK/C; Sulzer Spine-Tech, Minneapolis, MN) for treatment of degenerative disc disease of the cervical spine.

OBJECTIVES

To report clinical results with maximum 24-month follow-up of fusions performed with the BAK/C fusion cage.

SUMMARY OF BACKGROUND DATA

Threaded lumbar cages have been used during the past decade as a safe and effective surgical solution for chronic disabling low back pain. Threaded cages have now been developed for use in anterior cervical interbody fusions to obviate the need for allografts or autogenous bone grafting procedures while providing initial stability during the fusion process.

METHODS

Patients with symptomatic cervical discogenic radiculopathy were treated with either anterior cervical discectomy with uninstrumented bone-only fusion (ACDF) or BAK/C fusion cage(s). Independent radiographic assessment of fusion was made and patient-based outcome was assessed by visual analog pain scale and a Short Form (SF)-36 Health Status Questionnaire.

RESULTS

Data analysis included 344 patients at 1 year and 180 at 2 years. When the two cage groups (hydroxya, patite-coated or noncoated) were compared with the ACDF group, similar outcomes were noted for duration of surgery, hospital stay, improvements in neck pain and radicular pain in the affected limb, improvements in the SF-36 Physical Component subscale and Mental Component subscale, and the patients' perception of overall surgical outcome. Symptom improvements were maintained at 2 years. A greater percentage of patients with ACDF needed an iliac crest bone harvest than did BAK/C patients (67% vs.- 3%). Successful fusion for one-level procedures at 12 months was 97.9% for the BAK/C groups and 89.7% for the ACDF group (P < 0.05). The complication rate for the ACDF group was 20.4% compared with an overall complication rate of 11.8% with BAK/C. There was no difference in complications that necessitated a second operative procedure.

CONCLUSIONS

These results demonstrate that outcomes after a cervical fusion procedure with a threaded cage are the same as those of a conventional uninstrumented bone-only anterior discectomy and fusion with a low risk of complications and rare need for autogenous bone graft harvest.

Structural, psychological, and genetic influences on low back and neck pain: a study of adult female twins

OBJECTIVE

To assess genetic and environmental influences on low back and neck pain in a classic twin design and to examine the extent to which these are explained by structural changes seen on magnetic resonance imaging (MRI) and psychological and lifestyle variables.

METHODS

The subjects comprised 1,064 unselected women (181 monozygotic [MZ] and 351 dizygotic [DZ] twin pairs) recruited from a national registry of twin volunteers. Outcome measures included lifetime history of low back and neck pain (using a range of increasingly stringent definitions), MRI scores of disc degeneration in the lumbar and cervical spine, psychological distress as assessed by the General Health Questionnaire (GHQ), and lifestyle variables assessed by questionnaire.

RESULTS

For all definitions of pain, there was a consistent excess concordance in MZ when compared with DZ twins, equating to a heritability for low back pain in the range of 52-68% and for neck pain in the range of 35-58%. The strongest associations were between low back pain and MRI change (odds ratio [OR] 3.6, 95% confidence interval [95% CI] 1.8-7.3]) and between neck pain and response on the GHQ (OR 3.3, 95% CI 2.1-5.0). These associations were mediated genetically.

CONCLUSIONS

Genetic factors have an important influence on back and neck pain reporting in women. These factors include the genetic determinants of structural disc degeneration and an individual's inherited tendency toward psychological distress. MRI changes are the strongest predictor of low back pain.

Subsidence of stand-alone cervical cages in anterior interbody fusion: warning

Anterior cervical decompression and fusion with anterior plating of the cervical spine is a well-accepted treatment for cervical radiculopathy. Recently, to minimise the extent of surgery, anterior interbody fusion with cages has become more common. While there are numerous reports on the primary stabilising effects of the different cervical cages, little is known about the subsidence behaviour of such cages in vivo. We retrospectively reviewed eight patients with cervical radiculopathy operated upon with anterior discectomy and fusion with a stand-alone titanium cervical cage. During surgery, only the cartilage portion of the end plate was removed and the cages were filled with autologous cancellous bone graft from the iliac crest. To assess possible subsidence or migration, three different radiographic measurements in the sagittal plane were taken for each case, postoperatively and at the latest follow-up. Subsidence was defined as any change in at least one of our parameters of at least 3 mm. Follow-up time was 12-18 months (average 15 months). Five of the nine fused levels had radiological signs of cage subsidence. No posterior or anterior migration was observed. However, subsidence did not correlate with clinical symptoms in four of the five patients. The remaining patient with signs of subsidence, whose neck pain and neurologic symptoms had regressed in the early postoperative course, suffered recurrence of radiculopathy 6 months after the surgery. Her symptoms were explained by the subsidence of the cage and the subsequent foraminal stenosis observed on the magnetic resonance imaging (MRI) scan. At 15 months' follow-up, her cage was broken. Our preliminary results, so far limited in number, represent a serious warning to the proponents of stand-alone cervical cages

Cervical discography: clinical implications from 12 years of experience

STUDY DESIGN

Positive pain responses provoked in an inclusive series of cervical discograms performed over a 12-year period were categorized by level and reviewed.

OBJECTIVES

To report the prevalence of cervical pathology over an entire series of patients, to determine whether a reproducible pattern of concordant pain could be associated with each symptomatic level identified, and to calculate the rate of complications.

SUMMARY OF BACKGROUND DATA

Cloward wrote the first articles explaining the technique of cervical discography and reported on the pain responses induced. Currently, the technique is viewed as an invaluable diagnostic tool, but it also is criticized for failing to contribute unique information beyond that available from imaging studies despite the inherent risks.

METHODS

A series of 173 cervical discograms performed over 12 years was examined. Pain responses provoked and recorded during discography were grouped by disc level and examined for recurring patterns. The prevalence of disc pathology was calculated.

RESULTS

In all, 807 discs were injected, and 404 concordant pain responses (50%) were elicited. Three or more abnormal disc levels were identified in more than half of the patients. Complications developed in four patients (2.3%). No further complications were reported. Surgical treatment was indicated as viable in only 35 studies.

CONCLUSIONS

Discography is a safe and valuable diagnostic procedure showing characteristic pain patterns that may have clinical significance. In more than half of the studies, three or more levels were identified as pain generators, suggesting that treatment decisions based on information from fewer discs injected during discography may be tenuous.

Comparative study of thyroidectomies. Endoscopic surgery versus conventional open surgery

BACKGROUND

We have performed endoscopic thyroidectomy by an anterior chest approach and by an axillary approach. In this study, we evaluate the efficacy of these two types of endoscopic procedures and conventional open surgery.

METHODS

Each procedure was performed in 15 patients. The degree of surgical invasiveness and the nature of patients' complaints after surgery were compared using results of the operation and a questionnaire.

RESULTS

Although the mean operating time for the endoscopic procedure was significantly longer than for open surgery, there was no postoperative pain difference in the three groups. Three months after surgery, the incidence of swallowing discomfort was higher in the open surgery group than in endoscopic surgery group. All of the patients treated using the axillary approach were satisfied with the cosmetic results. However, three patients (20%) treated using the anterior chest approach and 11 patients (73%; p < 0.01) who underwent open surgery complained about the cosmetic results.

CONCLUSIONS

The incidence of postoperative complaints after endoscopic surgery is significantly lower than after open surgery. Patients treated using the axillary approach can obtain cosmetic results superior to those achieved with other procedures.

The efficacy of conservative treatment in patients with whiplash injury: a systematic review of clinical trials

STUDY DESIGN

A systematic review of the literature.

OBJECTIVES

To assess the efficacy of conservative treatment in patients with whiplash injuries.

SUMMARY OF BACKGROUND DATA

Many treatments are available for patients with whiplash injury, but there continues to be no evidence for their accepted use.

METHODS

A computerized literature search of Medline, Embase, Cinahl, Psychlit, and the Cochrane Controlled Trial Register was performed. Studies were selected if the design was a (randomized) clinical trial; if all patients had sustained a whiplash injury; if the type of intervention was a conservative one; if pain, global perceived effect, and participation in daily activities were used as one of the outcome measures, and if the publication was written in English, French, German, or Dutch. The methodologic quality was independently assessed by two reviewers by using the Maastricht-Amsterdam list. Three quality scores were calculated using this criteria list: the Overall Methodologic Quality Score, the Internal Validity Score, and the Delphi Quality Score. The conclusion of the review was based on articles that scored a quality score of at least 50% of the maximum available score on two of three quality scores.

RESULTS

Eleven studies met the inclusion criteria. Only three studies satisfied at least 50% on two of three ways of calculating a quality score, indicating overall poor methodology. There was a high rank correlation among the three ways of calculating a quality score. No statistical pooling was performed because of the heterogeneity of the interventions. This review indicates that active treatments show a beneficial long-term effect on at least one of the primary outcome measures.

CONCLUSION

Caution is needed when drawing a valid conclusion on the efficacy of conservative treatments in patients with whiplash injury. It appears that "rest makes rusty," whereas active interventions have a tendency to be more effective in patients with whiplash injury.

Specific Therapeutic Exercise of the Neck Induces Immediate Local Hypoalgesia

This study compared the effect of 2 specific cervical flexor muscle exercise protocols on immediate pain relief in the cervical spine of people with chronic neck pain. In addition, the study evaluated whether these exercise protocols elicited any systemic effects by studying sympathetic nervous system (SNS) function and pain at a location distant from the cervical spine. Participants were randomly allocated into either a cranio-cervical flexion (CCF) coordination exercise group (n = 24) or a cervical flexion (CF) endurance exercise group (n = 24). Measures of pain and SNS function were recorded immediately before and after a single session of the exercise interventions. Pain measures included visual analogue scale (VAS) ratings of neck pain at rest and during active cervical motion and pressure pain threshold (PPT) and thermal pain threshold (TPT) recordings over the cervical spine and at a remote site on the leg. Measures of SNS function consisted of blood flow, skin conductance, skin temperature, heart rate, and blood pressure. Immediately after 1 session of exercise, there was a reasonably sized increase of 21% (P < .001, d = 0.88) and 7.3% (P = .03, d = 0.47) in PPT locally at the neck for the CCF exercise and the CF exercise, respectively. There were no changes in local neck TPT with either exercise. Pressure pain threshold and TPT at the leg and SNS did not change after exercise. Only the CCF exercise demonstrated a small improvement in VAS ratings during active movement (change on 10-cm VAS: CCF, 0.42 cm (P = .04). This study shows that specific CCF therapeutic exercise is likely to provide immediate change in mechanical hyperalgesia local to the neck with translation into perceived pain relief on movement in patients with chronic neck pain.

PERSPECTIVE

This study showed an immediate local mechanical hypoalgesic response to specific exercise of the cervical spine. Understanding the pain-relieving effects of exercise will assist the clinician in prescribing the most appropriate exercise protocols for patients with chronic neck pain.

A cross-sectional study correlating cervical radiographic degenerative findings to pain and disability

STUDY DESIGN

A cross-sectional design was used to correlate cervical radiographic findings of spinal degeneration to neck pain and disability.

OBJECTIVES

The results were correlated to assess the clinical importance of radiographic spinal degeneration.

SUMMARY OF BACKGROUND DATA

Past investigations suggest little association between clinical findings and radiographic evidence of spinal degeneration. However, changes in activities of daily living and chronicity of complaint have not been investigated.

METHODS

Over a 5-month period, data were collected on 700 consecutive patients referred for cervical radiographic examination as part of their clinical evaluation. While in the radiology department, all subjects completed a visual analog pain scale, neck disability index, and short questionnaire, all of which quantified various aspects of any neck complaint. Relationships between indices of patient complaint and the number of cervical degenerative intervertebral discs were evluated using regression analysis.

RESULTS

A significant relationship (P < 0.001) was noted between the number of levels of intervertebral disc degeneration and the chronicity of cervical complaint. No significant relationship was found between cervical degeneration and past trauma (P = 0.904) or gender (P = 0.213). Multiple-regression analysis of visual analog pain scale scores revealed a significant two-way interaction with chronicity and past trauma (P = 0.007) and a significant main effect with gender (P < 0.001). Cervical degeneration was not significant as a main effect or interaction with other factors. Multiple-regression analysis of neck disability index scores demonstrated a significant three-way interaction of chronicity, degeneration, and gender (P = 0.022) and a significant two-way interaction for chronicity and trauma (P = 0.025). No additional information was gathered by multivariate multiple-regression techniques.

CONCLUSIONS

Increasing levels of spinal degeneration are related to increasing chronicity of patient complaints. Spinal degeneration is not related to past trauma or gender. Women, but not men, report higher disability with increasing levels of degeneration. Subjects with past trauma reported more intense pain and disability. Overall, men reported less neck pain and disability than women.

Impact of obesity on musculoskeletal pain and difficulty of daily movements in Japanese middle-aged women

OBJECTIVE

To investigate the impact of obesity on musculoskeletal pain and disability, which impairs well-being, associations between body mass index (BMI), frequency of musculoskeletal pain and difficulty of daily movements were assessed in middle-aged women.

METHODS

Subjects were 709 Japanese women in a community, aged 40-69. Measured BMI, current smoking habits, frequency of pain (pain score)(rarely (0), occasionally (1) or frequently (2)) during the last 1 month at shoulders, neck, upper back, lower back and legs, difficulty of three daily movements: walking continually for more than a half hour, climbing stairs and sitting on the floor with one's legs bent beneath one another, (score for each movement) (rarely (0), occasionally (1) or frequently (2)) by a questionnaire. The summed score was defined as the difficulty score of daily movements (DS) (0-6).

RESULTS

BMI increased significantly with age. Lower back pain (occasionally or frequently) was the most common symptom (40.3%) in the subjects. There was a peak in prevalence of frequent pain of shoulders at age 50. Pain score for legs and DS increased significantly with age. Higher BMI was related to increased prevalence of frequent leg pain and DS (>or=3), but there were no significant associations between age or BMI, and scores of back pain. DS was correlated significantly with pain scores at shoulders, upper back, lower back and legs. After adjustment for age and smoking habit using a logistic regression analysis, odds ratios for frequent pain at legs and DS (>or=3) were 4.02 (CI: 1.83-8.80) and 2.92 (CI: 1.56-5.47), respectively, in the obese women (BMI>or=26.4, n=61), compared with 401 women with normal BMI (20-24).

CONCLUSION

Obesity tended to impair well-being through musculoskeletal pain at legs and difficulty of daily movements in Japanese middle-aged women.

Migraine and the neck: new insights from basic data

The clinical presentation of pain in patients with migraine showing spread and referral of pain throughout the trigeminal and cervical innervation territories accompanied by hyperalgesia and allodynia indicates a dynamic trigemino-cervical interaction. The physiologic mechanisms may be convergence of trigemino-cervical afferents and central sensitization of trigemino-cervical neurons leading to dynamic neuroplastic changes during migraine. This review highlights the clinical phenotype and mechanisms of how nociceptive input from neck structures of the upper cervical spine are integrated into the trigemino-cervical system. The nociceptive input into the spinal cord also is subject to a modulation by segmental mechanisms in the spinal cord and by inhibitory projections from brain stem structures such as the periaqueductal gray. The functional relevance of these basic mechanisms is discussed with reference to recent studies using neurostimulation of afferent nerves aiming at pain modulation in patients with migraine.

Relationship between cervical lordosis and facial morphology in Caucasian women with a skeletal class II malocclusion: a cross-sectional study

Several published studies show a relationship between craniofacial morphology and head posture. The aim of this study was to evaluate the association between cervical lordosis angle and mandibular length from lateral skull radiographs, and to investigate the relationship between mandibular retrusion and cervical lordosis angle decreasing. The sample comprised 70 Caucasian adult women, average 27.4, in skeletal class II and Angle class II. Lateral skull radiographs were obtained in natural head position (mirror position). Ten morphological variables were individuated on tracings. In order to assess errors due to landmark identification, double measurements were made in ten randomly selected radiographs and were compared with Dahlberg's formula. A Sperman's rank correlation test showed a negative correlation (P < 0.01) between cervical lordosis and mandibular length (compensatory curvature of the cervical spine) and positive correlation between anterior cranial base and maxillary length (P < 0.05). Based upon the cross-sectional method, no conclusion was possible about the mechanism concerning these results. Future longitudinal studies in growing patients should be directed to understanding the extent of environmental and genotype influences on cervical lordosis angle.

Percutaneous vertebroplasty at C2: case report of a patient with multiple myeloma and a literature review

Percutaneous vertebroplasty (PVP) of the axis is a challenging procedure which may be performed by a percutaneous or a transoral approach. There are few reports of PVP at the C2 level. We report a case of unstable C2 fracture treated with the percutaneous approach. The fracture was the first manifestation of multiple myeloma in a previously healthy 47-year-old woman. After local radiotherapy and chemotherapy, the fracture was still unstable and the patient had been continuously wearing a stiff cervical collar for 9 months. Complication-free PVP resulted in pain relief and stabilization and use of the cervical collar could be discontinued. At 18 months follow-up the patient remained free from pain, the fracture was stable and she had returned to work. The purpose of this article is to present the technical facts and to highlight the benefits and potential complications of the procedure. The technical characteristics of the procedure, the indication and results of the present case are discussed together with previously reported cases of PVP treatment at C2.

Long-Term Results of Occipitothoracic Fusion Surgery in RA Patients with Destruction of the Cervical Spine

OBJECTIVE

This is a retrospective study of the outcome of occipitothoracic fusion surgery in rheumatoid arthritis (RA) patients with destruction of the cervical spine, designed to assess the efficacy of halo vest before surgery, the postoperative outcome, and the activities-of-daily living (ADL) problems associated with surgical management. There have been no reports regarding these issues, including surgical effect on subjacent vertebrae.

METHODS

This study included 20 RA patients with destruction of the cervical spine. All patients underwent preoperative halo vest followed by occipitothoracic fusion with an average follow-up of 5 years. The long-term clinical outcomes were analyzed using a modified Ranawat classification.

RESULTS

Before halo application, the neurologic status was assessed as IIIC in 15 patients and IIIB in 5 patients. After halo application, the neurologic status improved in all patients: IIIA in 12 patients and IIIB in 8 patients. After surgery, the neurologic status did not improve in six of the eight IIIB patients but improved to IIIA in two patients. Of the 12 IIIA patients, the neurologic status improved to II in 6 patients but did not improve in the other 6 patients. Patient satisfaction was excellent for 14 patients, good for 3 patients, and fair for only 3 patients (1 had difficulty drinking, another had back pain, and the last had low back pain associated with a compression fracture of the lumbar spine).

CONCLUSIONS

We have performed occipitothoracic fusion surgery in RA patients with destruction of the cervical spine. Preoperative halo vest was very effective for improving the neurologic status, for the general condition, and for an optimal sagittal alignment. Occipitothoracic fusion using unit rods gave satisfactory long-term clinical results compared with the prognosis of patients in whom the disease follows its natural course.

Spinal cord compression as a result of Rosai-Dorfman disease of the upper cervical spine in a child

BACKGROUND

Rosai-Dorfman disease is characterized by massive painless cervical lymphadenopathy, but can also include nasal obstruction, tonsillar enlargement, or hearing abnormalities. The disease occurs most often in the third and fourth decades. Most authors have suggested that it represents either an autoimmune disease or a reaction to an infectious agent that has yet to be discovered. Less than 50 cases of central nervous system involvement have been reported.

CASE ILLUSTRATION

We report a child with cervical spinal cord compression due to Rosai-Dorfman disease of the cervical spine.

PROGNOSIS

This disease has variable outcomes from relatively benign to insidious over decades. Our case is unusual in that the patient was a child and had involvement of the spine with resultant cord compression, a combination that has been reported rarely.

Transient cervical nerve root compression modulates pain: load thresholds for allodynia and sustained changes in spinal neuropeptide expression

Nerve root compression produces chronic pain and altered spinal neuropeptide expression. This study utilized controlled transient loading in a rat model of painful cervical nerve root compression to investigate the dependence of mechanical allodynia on load magnitude. Injury loads (0-110mN) were applied quasistatically using a customized loading device, and load thresholds to produce maintained mechanical allodynia were defined. Bilateral spinal expression of substance P (SP) and calcitonin gene-related peptide (CGRP) was assessed 7 days following compression using immunohistochemistry to determine relationships between these neuropeptides and compression load. A three-segment change point model was implemented to model allodynia responses and their relationship to load. Load thresholds were defined at which ipsilateral and contralateral allodynia were produced and sustained. The threshold for increased allodynia was lowest for acute (day 1) ipsilateral responses (26.29mN), while thresholds for allodynia on day 7 were similar for the ipsilateral (38.16mN) and contralateral forepaw (38.26mN). CGRP, but not SP, significantly decreased with load; the thresholds for ipsilateral and contralateral CGRP decreases corresponded to 19.52 and 24.03mN, respectively. These thresholds suggest bilateral allodynia may be mediated by spinal mechanisms, and that these mechanisms depend on the magnitude of load.

Ventral correction of postsurgical cervical kyphosis

OBJECT

Cervical kyphotic deformation may develop after surgery involving either the ventral or dorsal approach. Regardless of the cause, the development of a cervical kyphotic deformity should be avoided, if possible, and corrected if present, when appropriate. The authors describe their experience with a technique for the ventral correction of iatrogenic (postoperative) cervical kyphosis.

METHODS

A retrospective review of cases involving correction of postoperative iatrogenic cervical kyphosis via an ventral approach was performed. The authors conducted an ventral approach to kyphosis correction. The procedure required specific head positioning (in extension), convergent distraction pins, and an ventrally placed implant (axially dynamic when appropriate) with multiple points of fixation including at least one point of intermediate fixation. The pre- and postoperative sagittal angle and clinical status were evaluated. During a nearly 14-month period, 12 patients met the inclusion criteria. Ten patients underwent a minimum of 6 months of follow up. They comprised the study population. Most patients presented with mechanical neck pain as part of their symptom profile. The mean magnitude of deformity correction (pre- to postoperative) was 20 degrees of lordosis. The mean postoperative sagittal angle was 6 degrees of lordosis. The mean change in the sagittal angle during the follow-up period was 2.2 degrees of lordosis.

CONCLUSIONS

The ventral approach to correction of cervical deformity led to the achievement of lordosis in all but one patient. This posture was effectively maintained during the follow-up period. All patients exhibited improvement postoperatively; three experienced complete resolution of their preoperative symptoms. When symptoms are related to postsurgical kyphosis, deformity correction should be considered. Such a procedure may be performed effectively via an ventral approach in most circumstances.

Comparison of modic changes in the lumbar and cervical spine, in 3167 patients with and without spinal pain

BACKGROUND CONTEXT

There are few comparisons of Modic changes (MCs) in the lumbar and cervical spine.

PURPOSE

Compare the prevalence of MCs in the lumbar and cervical spine, and determine how MC prevalence depends on spinal pain, age, disc degeneration, spinal level, and the presence or absence of kyphosis.

STUDY DESIGN

Retrospective clinical survey.

MATERIALS AND METHODS

Magnetic resonance images (MRIs) were compared from five patient groups: 1. 1223 patients with low-back pain/radiculopathy only; 2. 1023 patients with neck pain/radiculopathy only; 3. 497 patients with concurrent low-back and neck symptoms; 4. 304 asymptomatic subjects with lumbar MRIs; and 5. 120 asymptomatic subjects with cervical MRIs.

RESULTS

The prevalence of MCs was higher in those with spinal pain than in those without, both in the lumbar spine (21.0% vs 10.5%) and cervical spine (8.8% vs 3.3%). Type II MCs were most common and Type III were least common in all groups. The prevalence of lumbar MCs in people with back pain was little affected by the presence of concurrent neck pain, and the same was true for the prevalence of cervical MCs in people with neck pain with or without concurrent back pain. When symptomatic patients were reclassified into two groups (back pain, neck pain), the prevalence of lumbar MCs in people with back pain was greater than that of cervical MCs in people with neck pain. The prevalence of lumbar and cervical MCs increased with age, disc degeneration, (descending) spinal level, and increased kyphosis.

CONCLUSIONS

There is a significantly higher prevalence of MCs in patients with back and neck pain. The reported association with increased kyphosis (flat back) is novel.

A new minimally invasive posterior approach for the treatment of cervical radiculopathy and myelopathy: surgical technique and preliminary results

Degenerative cervical disorders predominantly lead to anterior spinal cord compression (by bony spurs at the posterior margin of the vertebral body or by degenerated disc), which may be central and/or foraminal. In a smaller percentage of cases, there is encroachment of the canal mainly from posterior by bulging yellow ligaments or bony appositions, resulting in compression syndromes of roots or spinal cord. The aim of this work is to present a minimally invasive posterior approach avoiding detachment of muscles for the treatment of cervical radiculopathy and myelopathy. Thirteen patients suffering from cervical radiculopathy (four patients) or myelopathy (nine patients) were operated according to this technique. In principle, the technique secures access to the diseased spinal segment via a percutaneously placed working channel (11 mm outer diameter and 9 mm inner diameter). The cervical paraspinal muscles are not deflected, but just spread between their fibres by special dilators. All further steps are performed through this channel under control of three-dimensional vision through the operating microscope. The mean follow-up period was 17 months (one patient died 9 months postoperatively), and patients were evaluated using a modified version of the Oswestry Index, called the Neck Disability Index (NDI), and the visual analogue scale (VAS) for neck and arm pain. The mean NDI (P<0.0001) improved from 13.2 (preoperatively) to 4.8 (postoperatively). The VAS for arm pain (P<0.001) and for neck pain (P<0.001) also showed marked postoperative improvement. Complete recovery of the preoperative neurological deficit was found in four patients, while the remaining eight patients showed improvement of the neurological symptoms during the follow-up period. There were no intra-operative or postoperative complications and no re-operation. The preliminary experience with this technique, and the good clinical outcome, seem to promise that this minimally invasive technique is a valid alternative to the conventional open exposure for treatment of lateral disc prolapses, foraminal bony stenosis and central posterior ligamentous stenosis of the cervical spine.

Characteristics of sagittal vertebral alignment in flexion determined by dynamic radiographs of the cervical spine

STUDY DESIGN

This study was conducted to depict the change patterns of intervertebral motion of the cervical spine during flexion, upright, and extension positions using dynamic radiographs. Special interest was focused on the flexion position.

OBJECTIVES

To find reliable criteria for judging the normal intervertebral flexibility based on a survey of the normal population.

METHODS

The lateral dynamic radiographs of 75 normal subjects were analyzed by digitization and computer calculation. The characteristics of intervertebral positions were investigated using flexion radiographs.

RESULTS

From extension to flexion, the angles of intervertebral angular displacement changed from lordosis with different degrees to nearly 0 degrees, which means the adjacent endplates are almost parallel, except at C1-C2; the intervertebral translation changes from slightly retrolisthetic to zero displacement. Using C2-C3 as a baseline to calculate the intervertebral differences of angular displacement and translation in flexion radiographs, nearly all the intervertebral differences of angular displacement were less than 7 degrees, and those of translation were less than 0.06 mm.

CONCLUSIONS

Qualitative changes from extension to flexion and quantitative values of intervertebral differences in flexion radiographs help define the normal flexibility of the cervical spine more accurately.

Potential sources of neck and back pain in clinical conditions of dogs and cats: a review

Pathological neck and back pain occurs in many medical conditions of dogs and cats. Pain may arise from a variety of structures including the intervertebral discs, facet joint capsules, dorsal root ganglia, vertebral ligaments, the vertebral periosteum, and the meninges. The source of this pain is dependent upon the type of disease process and its location within or surrounding the spinal column. Diseases can directly or indirectly stimulate pain sensors (nociceptors). Inflammatory diseases may hypersensitize these receptors or nociceptive pathways with inflammatory mediating substances such as serotonin, histamine and potassium. Diseases resulting in mechanical compression of nociceptors or nociceptive pathways may also result in neck or back pain. A thorough understanding of spinal pain occurring in dogs and cats will lead to more accurate diagnoses and treatments and may provide information regarding prognoses for various diseases. Evidence pointing to sources of spinal pain taken from scientific and clinical studies of a variety of species including humans is provided. Suspected or known sources of neck and back pain occurring in several clinical conditions of dogs and cats are discussed.

Ingrowth of Nociceptive Receptors into Diseased Cervical Intervertebral Disc Is Associated with Discogenic Neck Pain

OBJECTIVE

To investigate the distribution of nociceptive nerve fibers in the cervical intervertebral discs of patients with chronic neck pain and determine whether these nociceptive nerve fibers are related to discogenic neck pain.

METHODS

We collected 43 samples of cervical intervertebral discs from 34 patients with severe chronic neck pain (visual analog scale [VAS] ≥ 70 mm), 42 samples from 36 patients who suffered cervical spondylotic radiculopathy or myelopathy without neck pain or with mild neck pain (VAS ≤ 30 mm) and 32 samples from eight donators to investigate their innervation immunohistochemically using an antibody against neuropeptide substance P.

RESULTS

The immunohistochemical investigation revealed that substance P-positive nerve fibers were obviously increased in number and deeply ingrown into the inner anulus fibrosus and even into the nucleus pulposus in the degenerative cervical discs of patients with severe neck pain in comparison with the discs of patients with cervical spondylotic radiculopathy or myelopathy and normal control discs (P<0.01).

CONCLUSIONS

The current study may indicate a key role of nociceptive nerve fibers in the pathogenesis of neck pain of cervical disc origin.

En bloc resection of a C4 chordoma: surgical technique

The prognosis of aggressive benign and low-grade malignant tumors in the spine as in the limbs, seems to be mostly related to the feasibility of en bloc resection, while in the treatment of high-grade malignant tumors the protocols of treatment include the combination of chemotherapy, radiation and surgery. Indications, criteria of feasibility and surgical technique are extensively reported for the thoracic and lumbar spine. In the cervical spine few cases are reported of resection, due not only to anatomical constraint, but also to the rarity of finding a tumor accomplishing the criteria of feasibility. A case of double-approach vertebrectomy finalized to remove en bloc the body of C4 for a stage IA chordoma is reported. The first stage was posterior, aiming to remove the posterior healthy elements by piecemeal technique. The anterior approach consisted of contemporary right and left prevascular presternocleidomastoid approaches The specimen was submitted for the histological study of the margins, which resulted tumor-free. This technical note is finalized to confirm that en bloc resection of the vertebral body through total vertebrectomy is feasible in the midcervical spine by double approaches, provided the tumor involves only layers B and C, maximum extension sectors 5-8.

Surgical management of syringomyelia-Chiari complex

Great variety exists in the indications and techniques recommended for the surgical treatment of syringomyelia-Chiari complex. More recently, magnetic resonance (MR) imaging has increased the frequency of diagnosis of this pathology and offered a unique opportunity to visualize cavities inside the spinal cord as well as their relationship to the cranio-cervical junction. This report presents 18 consecutive adult symptomatic syringomyelia patients with Chiari malformation who underwent foramen magnum decompression and syringosubarachnoid shunting. The principal indication for the surgery was significant progressive neurological deterioration. All patients underwent preoperative and postoperative MRI scans and were studied clinically and radiologically to assess the changes in the syrinx and their neurological picture after surgical intervention. All patients have been followed up for at least 36 months. No operative mortality was encountered; 88.9% of the patients showed improvement of neurological deficits together with radiological improvement and 11.1% of them revealed collapse of the syrinx cavity but no change in neurological status. None of the patients showed further deterioration of neurological function. The experience obtained from this study demonstrates that foramen magnum decompression to free the cerebro-spinal fluid (CSF) pathways combined with a syringosubarachnoid shunt performed at the same operation succeeds in effectively decompressing the syrinx cavity, and follow-up MR images reveal that this collapse is maintained. In view of these facts, we strongly recommend this technique, which seems to be the most rational surgical procedure in the treatment of syringomyelia-Chiari complex.

Sagittal Split Fractures in Multilevel Cervical Arthroplasty Using a Keeled Prosthesis

This is a case report of intraoperative sagittal split fractures in multilevel cervical disc replacement using a keeled prosthesis. The patient's clinical course is discussed and outcomes measured with the SF-36 questionnaire, oswestry disability index, and visual analog scale neck pain are compared with the other patients at our institution that have undergone multilevel disc replacement. The patient did well and has not had any complications related to the device used or fractures. The risks and techniques to avoid this complication when using a keeled prosthesis are discussed in detail.