Smoking as a predictor of negative outcome in lumbar spinal fusion

STUDY DESIGN

A review of the smoking habits in 426 patients who had been followed prospectively for 2 years after a lumbar spinal fusion procedure was conducted.

OBJECTIVE

To analyze the effect of pre- and postoperative smoking on clinical and functional outcome after lumbar spinal fusion.

SUMMARY OF BACKGROUND DATA

Several animal models have shown a negative effect of nicotine on spinal fusion. At this writing, the clinical effect of nicotine on spinal fusion has not been fully clarified.

METHODS

The study comprised 426 patients who underwent lumbar spinal fusion between 1993 and 1997. These patients received a mailed questionnaire regarding their tobacco consumption before and after their surgery. All other data, including preoperative clinical and functional status, were collected prospectively during a 2-year follow-up period. To assess functional outcome, the Dallas Pain Questionnaire was used.

RESULTS

The questionnaire was answered by 396 patients (93%). Of these patients, 54.5% (20% more than the background population) were smokers before the operation. Smoking of more than 10 cigarettes daily before the operation and attempted fusion at two or more levels increased the risk of nonunion: odds ratio, 2.01 (P < 0.016) and odds ratio, 3.03 (P < 0.001), respectively. Smoking cessation increased fusion rates to near those of nonsmokers. Smoking had no influence on functional outcome, as assessed by the Dallas Pain Questionnaire, but preoperative smoking predicted a negative answer to the question "Would you undergo the same treatment again, now that you know the result?" (odds ratio, 1.65; P < 0.054).

CONCLUSIONS

Smoking was shown to have a negative effect on fusion and overall patient satisfaction, but no measurable influence on the functional outcome as assessed by the Dallas Pain Questionnaire.

Recombinant bone morphogenetic protein-7 as an intracorporal bone growth stimulator in unstable thoracolumbar burst fractures in humans: preliminary results

The study presented here is a pilot study in five patients with unstable thoracolumbar spine fractures treated with transpedicular OP-1 transplantation, short segment instrumentation and posterolateral fusion. Recombinant bone morphogenetic protein-7 in combination with a collagen carrier, also referred to as OP-1, has demonstrated ability to induce healing in long-bone segmental defects in dogs, rabbits and monkeys and to induce successful posterolateral spinal fusion in dogs without need for autogenous bone graft. Furthermore OP-1 has been demonstrated to be effective as a bone graft substitute when performing the PLIF maneuver in a sheep model. Five patients with single-level unstable burst fracture and no neurological impairment were treated with intracorporal OP-1 transplantation, posterior fixation (USS) and posterolateral fusion. One patient with osteomalacia and an L2 burst fracture had an additional intracorporal transplantation performed proximal to the instrumented segment, i.e. OP-1 into T 12 and autogenous bone into T 11. Follow-up time was 12-18 months. On serial radiographs, Cobb and kyphotic angles, as well as anterior, middle and posterior column heights, were measured. Serial CT scans were performed to determine the bone mineral density at fracture level. In one case, radiographic and CT evaluation after 3 and 6 months showed severe resorption at the site of transplantation, but after 12 months, new bone had started to fill in at the area of resorption. In all cases there was loss of correction with regard to anterior and middle column height and sagittal balance at the latest follow-up. These preliminary results regarding OP-1 as a bone graft substitute and stimulator of new bone formation have been disappointing, as the OP-1 device in this study was not capable of inducing an early sufficient structural bone support. There are indications to suggest that OP-1 application to a fracture site in humans might result in detrimental enhanced bone resorption as a primary event.

Two-level spinal stenosis in minipigs. Hemodynamic effects of exercise

STUDY DESIGN

Twenty-two Göttingen minipigs were trained to run on a treadmill. Two-level lumbar spinal stenosis was created in 12 pigs, 10 were unoperated control subjects. Blood flow of the spinal cord and nerve roots was determined with microspheres at rest, during exercise, and after exercise.

OBJECTIVES

To study the effect of lumbar spinal stenosis and exercise on blood flow of spinal neural tissue.

SUMMARY OF BACKGROUND DATA

Neurogenic claudication, the key symptom of lumbar spinal stenosis, may be caused by vascular impairment or mechanical distress of neural tissue during exercise. Experimental compression of the cauda equina causes reversible nerve root edema, stasis, blood flow decrease, and compromised neural function. The vascular pathophysiology of spinal stenosis during exercise has not been studied previously.

METHODS

Pigs were trained daily for 3 months. Two-level 25% lumbar spinal stenosis was introduced by placement of stenosing bands around the dural sac. Neurologic function was monitored before surgery by evoked potentials and after surgery by the Tarlov score. Regional blood flow in lumbosacral neural tissue was measured 3 days after chronic catheterization using microspheres at rest, during exercise at 3 km/h for 15 minutes, and at rest 30 minutes after exercise.

RESULTS

Blood flow of grey and white matter increased during exercise in both groups, with no differences between groups. slight hyperemia prevailed after exercise in white matter of the stenotic area but not in grey matter. Nerve root blood flow was largely unchanged in control subjects during exercise but was reduced in spinal stenosis at rest, further depressed during exercise, and normalized after exercise. Dural blood flow was elevated throughout.

CONCLUSION

The study suggests that exercise-induced impairment of spinal nerve root blood flow plays a role in the pathophysiology of neurogenic claudication.

Regional blood flow, plasma volume, and vascular permeability in the spinal cord, the dural sac, and lumbar nerve roots

OBJECTIVES

This study quantified the regional blood flow (RBF), plasma volume (PV), and the vascular permeability (VP) in the spinal cord, spinal nerve roots, and the dural sac.

SUMMARY OF BACKGROUND DATA

Spinal cord hemodynamics have been investigated. However, the full segmental distribution of blood flow to the spinal cord and nerve roots has not been worked out. Vascular permeability of the spinal cord and nerve roots has been investigated but results regarding the spinal nerve roots have not been consistent.

METHODS

Eight Labrador dogs were used. Regional blood flow was measured with microspheres. Plasma volume and vascular permeability were assessed by the distribution spaces of radioactively labeled plasma proteins.

RESULTS

Regional blood flow was highest in the cervical and lumbar cord. Average (SEM) RBF values of the cord and spinal nerve roots were 10.4 +/- 1.0 and 4.4 +/- 0.5 mL/min 100 g, respectively. Plasma volume of the spinal cord was 0.85 +/- 0.06 mL/100 g and 1.29 +/- 0.17 mL/100 g in the spinal nerve roots. Vessels in the spinal nerve roots had significantly greater permeability to albumin than those of the spinal cord (P < 0.001).

CONCLUSIONS

The quantitative flow measurements showed the existence of three main anatomic territories in the cord. The vascular permeability of vessel in the spinal nerve roots appears greater than that of the spinal cord, indicating that spinal nerve roots are located outside the blood brain barrier. Diffusion might be one of the nutritional pathways to spinal nerve roots.

Badminton injuries--a prospective epidemiological and socioeconomic study

During a 1-year period 100 badminton players were registered and treated in the casualty ward of Randers City Hospital, Denmark. The injuries to the badminton players constituted 5% of all sports injuries registered during the same period in the casualty ward. At follow-up questionnaires were sent to all participants. Replies were received from 89 patients. Over the same period all sports participants in the hospital catchment area (30,254) were registered according to their sport affiliation (2620 badminton players-1650 men and 970 women). Of those injured 58% were men (mean age 31 years) and 42% were women (mean age 25 years). Of the injuries 55% occurred in club players, the remainder occurring during company and school sports activities. The active players were classified into three groups according to age: Group 1 under 18 years (31%); Group 2 18-25 years (16%); Group 3 more than 25 years (53%). According to the Abbreviated Injury Scale (AIS) 17% of the injuries were classified as minor, 56% as moderate, and 27% as severe, respectively. Of the severe injuries (AIS = 3) 56% were found in the oldest age group. AIS correlated with time absent from sport (P < 0.001). Nine players (9%) reported that earlier injuries had influenced the actual accident. Most players (96%) trained one to three times a week. Sprains were the injury most commonly diagnosed (56%), fractures accounted for 5%, torn ankle ligaments were found in 10%, and 13% had ruptures to the Achilles tendon. Overall, 21% were admitted to hospital. None of the patients treated as inpatients was kept in hospital for more than 7 days. The injury caused 56% of players to be absent from work of whom 23% were absent for more than 3 weeks. After the injury 12% of the players gave up their sport, and only 4% restarted their training/sport within 1 week. As many as 28% had to avoid training and playing in matches for 8 weeks or more.

Handball injuries. An epidemiologic and socioeconomic study

A total of 570 injuries in handball players were prospectively registered in a well-defined geographic area of 124,321 inhabitants. The incidence of handball injuries was 46 per 10,000 inhabitants per year. The incidence in women (61 per 10,000 per year) was double that of men (31 per 10,000 per year). Sixty-two percent of the injuries were ligament sprains and tears and 12% were fractures. A total of 7% of the patients were hospitalized and the total loss of income because of sick leave was $3870. Sixty-eight percent of the injured handball players were absent from handball more than 1 week. Surprisingly, 8% of the minor injuries resulted in a sick leave of more than 6 days.

European soccer injuries. A prospective epidemiologic and socioeconomic study

In 1 year, 715 patients with soccer injuries were registered and treated in the emergency department of Randers City Hospital. We did a prospective study of these patients using a questionnaire to determine the most common locations, types, mechanisms, and treatments of injury. Financial costs for society and the individual were also examined. Forty-nine percent of the injuries were to the joints; sprains and contusions were the most common types of injury, accounting for 46% and 25%, respectively. The majority of patients (64% of the men and 58% of the women) were injured during physical contact with another player. Most (63%) of the patients were treated in the emergency department and then released. Thirty-one percent had to be absent from work, but only 8% of the patients had a loss of income because of their injury. The average amount of work time lost was 5 days.

Arteriovenous shunting is not associated with venous congestion in bone. Knee tamponade studied with 15-microns and 50-microns microspheres in immature dogs

Blood flow in the hind-limb bones of 8 immature labrador dogs with unilateral knee joint tamponade at 75 percent of the mean arterial pressure was measured with 15-microns and 50-microns microspheres to determine whether or not arteriovenous shunting occurs in bone with venous congestion caused by increased outflow resistance. The intraosseous pressure was 43 percent of the mean arterial pressure in the experimental distal femoral epiphysis versus 14 percent in the control knee (P less than 0.001). No pressure changes were found in the distal femoral metaphysis. Regional blood flow with 15-microns microspheres decreased centrally in the distal femoral epiphysis and increased centrally in the proximal tibial epiphysis. Metaphyseal blood flow was largely unchanged. A net shift in the preferred embolization site of 50-microns microspheres relative to that of 15-microns microspheres from central to peripheral regions occurred within both juxtaarticular epiphyses, indicating arteriolar vasodilation, but the relation between the uptake of the two microsphere sizes was unchanged when the epiphyses and other bony flow compartments were viewed in toto. The result speaks against the hypothesis of arteriovenous shunting in intraosseous hypertension.

Technetium 99m diphosphonate uptake and intraosseous hemodynamics during venous congestion in bone. Knee joint tamponade studied in immature dogs

Venous congestion in bone is a common early feature of inflammatory and degenerative joint diseases. An experimental study was performed of the relationship between the scintigraphic appearance of joints and the intraosseous hemodynamics during venous congestion caused by obstruction of the osseous venous drainage by increased intra-articular pressure. Intra-articular pressure was raised to 75% of mean arterial pressure in one knee each of 8 immature dogs. This caused elevated intraosseous pressure in the distal femoral epiphysis but not in the metaphysis. The elevated intraosseous pressure in the affected femoral epiphysis was associated with decreased technetium 99m diphosphonate uptake and blood flow, unaltered vascular volume and tissue hematocrit, and prolonged transit time of blood in the central cancellous bone. The decreased radionuclide uptake during intraosseous venous congestion thus appeared to reflect a decreased blood supply. However, by multiple regression analysis, the diphosphonate uptake in bone generally varied positively with blood flow and plasma volume and inversely with red cell volume in a nonlinear, multifactorial relationship.