[Blood flow changes in the legs of patients with disc herniation and spinal canal stenosis]

Blood flow changes through the leg were examined by thermography, heated thermocouple technique and straingauge plethysmography in patients with lumbar-disc herniation and spinal canal stenosis. Hypothermal areas were observed in the affected leg in disc herniation and of both legs in spinal canal stenosis. An increased blood flow through the anterior tibial muscle during sustained contraction was slightly depressed, and post-contraction hyperemia showed an increase in amount and duration in disc herniation. Levels of resting arterial inflow through the leg were almost half that of healthy individuals, and reactive hyperemia after walking revealed a marked prolongation especially in spinal canal stenosis. In postoperative cases of spinal canal stenosis the thermogram and arterial inflow of the leg returned to their normal level. These results can provide evidence of latent ischemia of the leg that may be caused by a radicular or sympathetic dysfunction in the lumbar spinal diseases.

Lumbar spinal stenosis. Clinical features, diagnostic procedures, and results of surgical treatment in 68 patients

Our experience with 68 patients with strictly defined, myelographically proven, surgically confirmed lumbar spinal stenosis seen over a 30-month period was reviewed. Pseudoclaudication was the commonest symptom (94%) and was described by patients as pain (93%), numbness (63%), or weakness (43%). Symptoms were frequently bilateral (68%) and generally relieved by flexing the lumbosacral spine. Neurologic abnormalities were found in a minority of patients and were usually mild. Electromyography showed one or more lumbosacral radiculopathies in 34 of 37 patients examined. Radiographic evidence of degenerative disk or joint disease was found in 63 patients. All patients had stenosis on myelography, with narrowing at L2, L3, and L4 being the commonest; 30% had multi-level stenosis. Two of ten computed tomograms were normal. Surgery was extensive; 72% of patients had three or more laminae removed. At a mean of 4 years after surgery, 84% of patients reported that surgery had yielded good to excellent results.

Our experience with lumbar spinal stenosis in Singapore

This is a study of 34 cases of lumbar spinal stenosis operated in the University Department of Orthopaedic Surgery from August 1973 to April 1980. Eleven cases were due to degenerative stenosis, 4 due to degenerative spondylolisthesis, 1 developmental, 3 post-fenestration/laminectomy, 1 post-fusion and 14 cases were due to combined aetiology. The average length of follow-up was 2.3 years. The clinical radiological and operative diagnostic features were analysed. Decompression alone was performed in 16 cases. Discectomy was also carried out in 16 cases and primary fusion in 3 cases. Good relief of backache, sciatica and neurogenic intermittent claudication was achieved in most cases. The majority were also able to return to their previous occupation, the average time taken being 4.9 months. 77% of cases gave either excellent or good results. The complications were spinal instability in 2 cases, impotence in 1 case, intra-operative nerve root damage in 2 cases and superficial wound infection in 1 case. Further surgery (lateral gutter fusion) was performed in only 1 case.

[Long-term results of the surgical treatment of lumbar stenosis]

Among 163 patients who underwent surgery for a degenerative lumbar stenosis, 79% were re-examined and evaluated retrospectively (2 to 14 years following surgery), using a functional grading scale. The grading scale (up to 20) assessed limping, radicular pain at rest and with effort, back pain, motor deficits, sphincter dysfunction, medication required, and quality of life. Satisfactory results were obtained in 83% with 87% reporting substantial functional improvement. Limping and radicular pain at rest responded most rapidly to surgical intervention. Subsequent disappearance of residual radicular pain occurred in 13% whether present at rest or with effort. Episodic radicular pain with effort persisted however, in approximately one-quarter of all patients, generally in those with more pronounced pain before surgery. One out of four patients had complete relief of back pain and most often without performing an arthrodesis. Major neurological deficits resolved extremely slowly but completely in six out of ten patients. On the grading scale of 20, four recovery profiles could be identified: a perfectly stable result (60%), regular improvement (14%), improvement with episodic aggravation of symptoms (19%) and subsequent worsening (8%). Overall, a second surgical intervention had to be performed in 5% of patients with complete bony excision or arthrodesis (for vertebral slippage or for back pain).

Simultaneous measurement of intraosseous and cerebrospinal fluid pressures in lumbar region

Intraosseous pressure (IOP) and cerebrospinal fluid pressure (CSFP) in the lumbar region were measured simultaneously in two groups of patients with either spinal canal stenosis or disc herniation, to compare dynamic changes with positional changes, and to learn whether these pressure changes may have some role in the onset of claudication. IOP and CSFP showed almost the same change patterns with positional changes in two groups. They were lowest in the prone position and highest at the standing position. In standing with flexion, they were almost the same as in the prone position, but in extension they increased above the standing pressure. These dynamic pressure changes could act as a compression force to the cauda equina in the patient with spinal canal stenosis.

Lumbar spinal stenosis: analysis of pre- and postoperative somatosensory evoked potentials

Cortical somatosensory evoked potential (CSEP) examinations were performed of 20 patients with lumbar spinal stenosis a day prior to surgery and 10 to 12 days after spinal decompression and bilateral lateral fusion. CSEPs were recorded to Cz-Fz (10-20 international EEG system) following stimulation of 32 tibial, peroneal and sural nerves and 16 saphenous nerves. A total of 110 nerves were examined. Using CSEP P1 latency as criteria for inclusion in the study, 21 tibial, 20 peroneal and 17 sural nerves were subjected to paired two-tailed t tests to determine whether the CSEP changes that occurred postoperatively were statistically significant (p less than 0.05). Postoperative P1 latencies of tibial, peroneal, and sural nerves changed significantly as well as N1 latencies and P1-N1 amplitudes of tibial and peroneal nerves. Nineteen patients improved clinically. It is postulated that pathologic narrowing of the spinal canal in spinal stenosis leads to nerve root compression and ischemia with resultant dysfunction primarily affecting large diameter myelinated fibers and that decompression procedure may adequately relieve the underlying pathologic processes. Improvement in CSEPs may be from increase in available numbers of functioning large diameter myelinated fibers, conversion to normal from a conduction block, and, perhaps, improved axoplasmic flow.

Redundant nerve roots in patients with degenerative lumbar spinal stenosis

Extensive fundamental and clinical investigations have been performed concerning redundant nerve roots (RNR) and the pathogenesis of cauda equina claudication (CEC) in degenerative lumbar canal stenosis (DLCS). These investigations consisted of (1) anatomic observations on RNR in 117 fixed cadaveric specimens, (2) myelographic study in 117 patients with or without DLCS, (3) operative observation on neural elements with special reference to the cauda equina in 56 DLCS patients (including a postoperative follow-up), and (4) electrophysiologic tests using spinal cord action potential recording under walking load preoperatively and intraoperative measurement of nerve conduction velocity of RNR. The RNR have neuronal losses resulting from a longer duration stenosis that suggests a sort of friction neuritis. Complicated factors contribute to the pathogenesis of CEC and the development of root gripping, such as the magnitude of RNR, the extent of the stenosis, a narrowed sac, age-dependent axial shortening of the spinal canal, and dynamic or postural factors. In cases with severe RNR, satisfactory operative results can be obtained only after thorough decompression with dural incision.

The syndromes of low back disease

The details of the various clinical syndromes are presented in the text, with further expansion by the various references. I attempted to summarize these in Tables 1 and 2. As in all aspects of medicine, the ultimate disease problem is a blend of various factors. Probably no single syndrome can stand alone without aspects of the others, but if a rational treatment plan is to be undertaken, some framework for action must be involved.

The pathophysiology of degenerative disease of the lumbar spine

Degeneration starts in one joint and eventually involves all three joints of the three-joint-complex (one disc and two posterior joints) at an intervertebral level. Later, mechanical changes occur that affect the levels above and below and cause similar changes there. The result is multilevel lumbar spondylosis and stenosis. The spectrum of degenerative changes in a three-joint-complex progresses through three stages, which help to predict the outcome of different types of treatment.

Stenosis and movement of the cervical spine in cervical myelopathy

The width of the spinal canal in 55 patients with cervical myelopathy was compared to a control group of 225 patients without myelopathy. There was a statistically significant narrowing of the cervical canal in the patients with cervical myelopathy, especially in men. Neck movement in the sagittal plane was studied in pantopaque myelograms in 43 patients with cervical myelopathy. It was found that retroflexion causes the most severe narrowing of the spinal canal. Patients with congenital cervical stenosis showed the greatest changes. Sagittal movement of the cervical spine was measured 1--3 years after the Cloward fusion operation in 38 patients and compared to a corresponding age group of 33 and a younger group of 26 healthy controls. The fusion of two or more vertebrae leads to considerable limitation of sagittal movement of the cervical spine on the average of 23,5 degrees in comparison with 40,6 degrees in the corresponding age control group. With the increasing age, anteflexion and retroflexion deteriorate equally, whereas the fusion operation restricts mainly the retroflexion of the cervical spine. In fact, the therapeutic effect of the Cloward operation seems to lie in the restriction of movement of the cervical spine.