Evaluating Low Back Pain Patients for Prolapsed Interverbral Disc in a Kenyan Teaching Hospital Patients and Methods

Background 
Accurate evaluation of low back pain is essential for its rational management. The extent of use of clinical and imaging findings in identification of prolapsed intervertebral disk varies between centers. In Kenya, the diagnostic procedure is obscure. 
Objective 
To assess the evaluation of low back pain patients for prolapsed intervertebral disk at Kenyatta National Hospital, a teaching and referral hospital in Kenya. 
Study Design 
A retrospective chart study Patients and Methods Historical, physical and imaging findings of patients who presented with 
low back pain and subsequently diagnosed with prolapsed inter-vertebral disk between Jan 1997 and December 2007 were evaluated. 
Results 
Of the six hundred and three patients (267 males, 336 females) who were evaluated, risk factors were recorded in 39.5% patients, 35.3% patients had sciatica while straight leg raising test was performed in 52.2% patients. Investigations performed in these patients included plain roentograms (38.5%), CT scan (9.1%) and MRI (44.1%). 
Conclusion 
The evaluation of low back pain for prolapsed inter-vertebral disk was incomplete. History of sciatica, SLRT, crossed SLRT and MRI use are recommended for routine evaluation of low back pain for PID.


Introduction
Background Accurate evaluation of low back pain is essential for its rational management. The extent of use of clinical and imaging findings in identification of prolapsed intervertebral disk varies between centers. In Kenya, the diagnostic procedure is obscure.

Objective
To assess the evaluation of low back pain patients for prolapsed intervertebral disk at Kenyatta National Hospital, a teaching and referral hospital in Kenya.

Patients and Methods
Historical, physical and imaging findings of patients who presented with low back pain and subsequently diagnosed with prolapsed inter-vertebral disk between Jan 1997 and December 2007 were evaluated.

Results
Of the six hundred and three patients (267 males, 336 females) who were evaluated, risk factors were recorded in 39.5% patients, 35.3% patients had sciatica while straight leg raising test was performed in 52.2% patients. Investigations performed in these patients included plain roentograms (38.5%), CT scan (9.1%) and MRI (44.1%).

Conclusion
The evaluation of low back pain for prolapsed inter-vertebral disk was incomplete. History of sciatica, SLRT, crossed SLRT and MRI use are recommended for routine evaluation of low back pain for PID. Lasegue test are 89% and 52%, respectively (7,8). Further, SLR has utility as a screen of lumbar spine stability, and can assess control of lumbar rotational movements (9) and when used with imaging, it ameliorates accuracy (10). Another significant observation of the present study is that while the crossed straight leg raising test has a relative higher specificity of 84% (7), it was not performed in any of the patients. Accordingly, it is probable that accuracy of clinical diagnosis is often undermined in patients at KNH and irrational treatment instituted.
While MRI is the gold standard diagnostic test for prolapsed disk worldwide (7,11), it is used in less than half of our patients. This could be attributed to high cost and low availability of this useful tool. Although a few patients had disc prolapse or herniation with a non-degenerated disc, there is a relationship between the presence of disc degeneration and prolapse or herniation on MRI (11). Unfortunately, MRI is so sensitive that frequently it over diagnoses PID (12).
Plain X-ray was done in 38.5% of all the patients. The consensus based on guidelines issued by the Royal College of Radiologists, however, is that plain lumbar spine X-rays are not indicated routinely in cases of possible PID. In fact during conservative management, there is no justification for it in the absence of other indications (12). Its use in KNH should therefore be reduced. Observations of the current study reveal that CT scan was ordered in less than 10% of the patients. In many places, because of its wider availability, lower cost, patient acceptability and effectiveness CT scan is the investigation of choice (13). It is carried out in most places especially where MRI may not be done due to non availability, high cost, claustrophobia on the part of the patient or contraindication due to metal implants (6). Further the Original article with non traumatic co-morbidities. In the majority (60.5%) of the patients, risk/co-morbid factors were not recorded. In 47.8% of the patients, the clinicians did not document performing the straight leg raising test.
Where performed, the test was negative in 61.5% of cases (table 1).
The spectrum of radiological investigations ordered in these patients included MRI (44.1%), lumbosacral X-ray (38.5%) and CT scan (9.1%). In 50 patients (8.3%) no imaging test was done. The lumbosacral X ray was consistently requested throughout the period while the MRI services were popular in the recent years ( Figure 1).
Most (82%) patients with sciatica had MRI features consistent with prolapsed intervertebral disk.

Discussion
Prolapsed intervertebral disk is diagnosed on history of back pain, sciatica, positive straight leg raising test and positive imaging finding consistent with prolapsed intervertebral disk (7). In the present study, 37% of patients