H. Alan Crockard

Quantitative assessment of cervical spondylotic my elopathy by a simple walking test

BACKGROUND We developed a 30 m walking test as a quantifiable measure of severity of cervical spondylotic myelopathy (CSM), which will be of use in determining the effects of decompressive surgical treatment. METHODS Preoperative measurements were made in 41 patients with CSM of 30 m walking times, number of steps taken over this distance, myelopathy disability index (MDI), and Nurick scores. The walking factors were compared with a similar number of age-matched and sex-matched controls. The individuals in the study were patients with CSM and no other relevant pathology consecutively referred for decompressive surgery to the National Hospital for Neurology and Neurosurgery. FINDINGS Both walking time and the number of steps taken were significantly worse in pre-operative patients than in controls. The walking data were highly reproducible over three trials. Postoperatively, there was a significant improvement in walking time (p=0.0018) and number of steps taken (p=5.87 x 10(-6)). Only two of 41 patients were worse postoperatively. There was also a significant improvement in MDI (two-tailed Wilcoxon, related samples; p<0.0001) and Nurick scores (two-tailed Wilcoxon p<0.0001) postoperatively. The preoperative and postoperative walking scores were significantly and equally correlated with the MDI and Nurick scores. INTERPRETATION Timed walks are an easily performed, quantitative, and valid means of assessing CSM and the effects of surgery.

Biocompatible Osteoconductive Polymer Versus Iliac Graft: A Prospective Comparative Study for the Evaluation of Fusion Pattern After Anterior Cervical Discectomy

Study Design One hundred fifteen patients having symptomatic cervical disc disease were recruited prospectively for this study. They were allocated randomly for either autologous iliac bone graft or biocompatible osteoconductive polymer implants. Both groups were compared clinically and radiologically. Objectives Complications, long‐term clinical and radiologic outcome, and hospital stay were compared to determine if biocompatible osteoconductive polymer was an improvement on iliac bone graft in terms of reduced donor site pain and shortened hospital stay. Summary of Background Data Donor site morbidity is a significant problem in anterior cervical fusion. Hospital stay is another factor in the recent era of cost consciousness. Biocompatible osteoconductive polymer has been used in many centers as a biodegradable implant to circumvent these problems. Methods Smith‐Robinson technique was used in 74 patients, and Cloward technique was used in 41 patients. Sixty‐five patients had biocompatible osteoconductive polymer implants, and 50 patients had iliac bone graft. Patients were followed‐up routinely in the outpatient clinic where pain visual analogue scale and Odoms criteria were used for outcome evaluation. Plain radiography, computed tomography scan, and magnetic resonance imaging were used for radiologic evaluation. Results The mean hospital stay was 4.8 days for those with iliac bone graft and 4.7 days for those with biocompatible osteoconductive polymer. Clinical outcome was identical in both groups. The incidence of partial graft protrusion and postoperative intersegmental kyphosis was statistically higher with iliac bone graft (P = 0.018 and P = 0.02, respectively). “Sclerosis” started to form around biocompatible osteoconductive polymer like a “halo” at 2 months. It increased with time, and sometimes was associated with new osteophyte formation; however, there was no biocompatible osteoconductive polymer incorporation or biodegradation. Conclusions Biocompatible osteoconductive polymer acts as a good “spacer” that reduces graft collapse and intersegmental kyphosis. However, it did not show any radiologic evidence of biodegradation or incorporation during the follow‐up period of 24 months.

Behavior of an extradural pressure monitor in clinical use: Comparison of extradural with intraventricular pressure in patients with acute and chronically raised intracranial pressure

A comparison of intraventricular pressure (IVP) and extradural pressure (EDP) was carried out in 17 patients being investigated for normal-pressure hydrocephalus, and in six patients with acutely raised intracranial pressure following events such as head injury or intracerebral hematoma. Extradural pressure was measured using the CardioSearch monitor. There was a reasonably good correlation between EDP and IVP in the chronic stable group with pressures up to 25 mm Hg. In the acute group there was no predictable relationship between EDP and IVP, and during a 24-hour period the pressures could vary by as much as 30 mm Hg. Subdural pressure, measured with the same instruments, was compared to IVP in both acute and stable situations in eight other patients: there was a close and constant correlation between pressures in these two spaces. The authors conclude that misleading information may be obtained from EDP monitoring, and erroneous management decisions may result from dependence on such a technique. Possible explanations for this are discussed.

Occipitocervical stabilization for myelopathy in patients with rheumatoid arthritis. Implications of not bone-grafting.

Background: Approximately 0.9 percent of the white adult population of the United States and 1.1 percent of the adult population in Europe are affected by seropositive rheumatoid arthritis. As many as 10 percent of those patients may need an operation for atlantoaxial subluxation. Severe instability, especially when associated with vertical subluxation of the odontoid process, can result in progressive cervical myelopathy. Typically, occipitocervical fixation has been performed for these patients with use of autograft bone to achieve long-term stability through a solid fusion. Harvesting the bone graft increases the operative risk to the patient and may result in increased morbidity. In our experience, patients who have had no clear radiographic evidence of fusion following use of occipitocervical instrumentation seemed to have done as well as those who have had obvious fusion. One assumption is that the clinical improvement might be attributable simply to stabilization of the joint rather than to osseous fusion. A longitudinal study was performed on patients with rheumatoid arthritis who required an operation because of craniocervical or upper cervical instability. Methods: The results of clinical, radiographic, functional, and self-evaluations were studied to determine the efficacy of treatment and to compare the outcomes of bone-grafting with those of procedures done without bone-grafting in a group of 150 patients who underwent posterior occipitocervical stabilization with use of a contoured metal implant (a Ransford loop) that was affixed by sublaminar wires. Internal fixation was performed in 120 patients without bone-grafting and in thirty patients with use of autogenous bone-grafting. Preoperatively, 23 percent (thirty-five) of the 150 patients had mild neurological involvement (class II, according to the system of Ranawat et al.), 45 percent (sixty-eight) had objective findings of weakness and long-tract signs but were able to walk (class III-A), and 29 percent (forty-three) were quadriparetic and unable to walk (class III-B). The age of the patients at the time of the operation ranged from twelve to eighty-three years (mean, sixty-two years). Results: There were significant improvements in postoperative Ranawat classes at all time-periods (range, p < 0.00005 to p = 0.0066) and in patient ratings of neck pain (range, p < 0.00005 to p = 0.0044) compared with preoperative scores. With the numbers available, there were no significant differences between the patients managed with a graft and those managed without grafting with respect to survival after the operation, Ranawat class, head or neck-pain rating, presence of subaxial abnormalities, radiographic craniovertebral motion, or vertical subluxation. Overall mortality at one month was 10 percent (fifteen of 150), although this value varied directly with the degree of preoperative disability. A second cervical spine operation was required in 11 percent (sixteen) of the 150 patients. Conclusions: While patients who have rheumatoid disease with anterior atlantoaxial subluxation should be treated with posterior atlantoaxial arthrodesis with use of bone-grafting and internal fixation, we believe that those who present with vertical instability and multilevel involvement can be treated with posterior occipitocervical stabilization with use of a contoured occipitocervical loop and sublaminar wire fixation without bone-grafting. Furthermore, we believe that the use of preoperative traction, bone cement, or a postoperative halo vest is unnecessary. Avoiding the harvesting of autogenous bone for grafting reduced the morbidity of this operation without compromising the outcome in these already sick patients.

The Glasgow Coma Score: reliable evidence?

The Glasgow Coma Score (GCS) is an important factor in the management and prognosis of a patient with neurosurgical pathology. We have found that there is often a disparity between the quoted and actual GCS of patients referred to this unit. We performed a prospective observational study to determine the proportion of patients referred with a correct GCS. Forty-two (51%) out of a total of 82 patients had a correct GCS on referral. The proportion of patients referred with a correct GCS did not vary with either the grade or speciality of the referring doctor.