Posterolateral uninstrumented fusion

Surgical treatment for the painful motion segment: matching technology with the indications: posterior lumbar fusion

STUDY DESIGN

A convenience literature-based review of the different techniques of posterior lumbar fusion.

OBJECTIVE

To describe the history, specific techniques, and outcomes of different methods of posterior lumbar fusion. The specific methods that were described include 1) uninstrumented posterior, posterolateral, and facet fusion, and 2) instrumented fusion using pedicle screws or facet screws.

SUMMARY OF BACKGROUND DATA

There are various posterior fusion techniques available for the treatment of degenerative lumbar spine conditions. Each individual technique has specific technical demands, indications, advantages, and disadvantages which should be taken into consideration when performing these procedures.

METHODS

The published scientific literature on the different methods of posterior lumbar fusion was reviewed. The history, indications, advantages, disadvantages, and clinical and radiographic outcomes were described based on the literature search.

RESULTS/CONCLUSIONS

Posterior fusion techniques have been and will continue to be among the most commonly performed procedures in lumbar spine surgery. The different methods of fusion are well defined, as are the possible complications and outcomes. They are effective techniques when performed on appropriately selected patients by a surgeon knowledgeable in the techniques and indications. Further studies are needed regarding promising but relatively unproven developments such as minimally invasive surgery and the use of osteoinductive agents.

Referral guidelines: carpal tunnel syndrome

The contribution on the postoperative management and rehabilitation of patients with carpal tunnel syndrome should be carefully considered by every surgeon. The operation is simply not over when the last stitch goes in; careful postoperative management is quite important if one is to obtain optimal surgical results. The principles outlined here are valuable and help to explain the occasional poor outcome. We have become convinced that the use of a dorsal splint in the 1st week to 10 days following surgery is a helpful measure. It is designed to prevent the median nerve from prolapsing forward and becoming adherent to or trapped by the edges of the severed transverse carpal ligament. With regard to surgical management of carpal tunnel syndrome. It is exceedingly important to continue producing outcome studies showing that our interventions really do eliminate the problem and allow people to return to productive work. Templates for outcome assessment are under development by the Outcomes Committee of the American Association of Neurological Surgeons and the Congress of Neurological Surgeons and also by the American College of surgeons. Hopefully, they can be applied to the treatment of carpal tunnel syndrome. The following segment represents some suggested referral guidelines for patients with carpal tunnel syndrome. The present differential diagnosis, methods of confirming the diagnosis, and appropriate indications for considering surgery. These guidelines have been reviewed by the various authors who have contributed to this issue of Neurosurgical Focus and other colleagues in neurosurgery, orthopedics, plastic surgery, neurology, and occupational therapy. It is hoped that they will be a reasonable start in our efforts to inform referring physicians as to the nature of median thenar neuropathy and its overall management.

Stress fracture of the pedicle after extensive decompression and contralateral posterior fusion for lumbar stenosis. Report of three cases

Lumbar spinal stenosis can be effectively treated by performing an extensive ipsilateral spinal decompression, including a partial pediculotomy, and contralateral posterior bone fusion. Infrequently, complications can arise following radical decompression to alleviate symptoms of stenosis, and one such complication is a pedicle fracture. Three reports of pedicle fractures following extensive spinal decompression and contralateral posterior fusion are detailed. This complication is emphasized, and interventions are discussed. Three patients presented with symptoms attributable to lumbar stenosis; they were initially treated with an ipsilateral decompression, achieved in part, through a partial pediculotomy followed by contralateral autologous bone fusion. Initially, all three patients improved postoperatively; however, they later developed neurological symptoms ipsilateral to the side of spinal decompression. Computerized tomography scanning demonstrated pedicle fractures on the decompressed side. This complication has not yet been reported in association with decompression and fusion for lumbar stenosis. Two of the patients developed leg pain necessitating reoperation whereas the third experienced only mild transient symptoms. The fractured pedicle was removed in one patient; laminar and spinous process fusion was performed again. Another patient underwent a total laminectomy, removal of the fractured pedicle, and bilateral transverse process fusion. Reoperation yielded satisfactory outcomes. The third patient's symptoms resolved without intervention. Pedicle fractures are a potential complication of extensive lumbar decompression and contralateral posterior fusion. Loading forces from the facets or transverse processes are possibly the cause of such fractures. Removal of the fractured pedicle, additional decompression, and enhanced bone fusion are recommended when the symptoms warrant surgical intervention.

Lumbar intradiscal pressure after posterolateral fusion and pedicle screw fixation

In vitro biomechanical testing was performed in single-functional spinal units of fresh calf lumbar spines, using pressure needle transducers to investigate the effect of posterolateral fusion (PLF) and pedicle screw constructs (PS) on intradiscal pressure (IDP), in order to elucidate the mechanical factors concerned with residual low back pain after PLF. IDP of 6 calf lumbar spines consisting of L4 and L5 vertebrae and an intervening disc was measured under axial compression, flexion-extension and lateral bending in the intact spine, PS, PLF and the destabilized spine. Relative to the intact spines, the destabilized spines showed increased IDP in all of lordings and moments. IDP under PS and PLF were significantly decreased in axial compression, extension and lateral bending loads (p<0.05). In flexion, IDP under PS and PLF increased linearly proportional to the magnitude of flexion moment and reached as high as IDP of the intact spines. These results demonstrated that despite an increase in the stiffness of motion segments after PLF and PS, significant high disc pressure is still generated in flexion. Flexibility of PS and PLF may cause increased axial load sharing of the disc in flexion and increased IDP. This high IDP may explain patients' persisting pain following PS and PLF.

Posterolateral lumbar fusion using facet joint fixation with biodegradable rods: a pilot study

Roentgen stereophotogrammetric analysis (RSA) was used to assess whether there is a potential for biodegradable rods crossing the denuded facet joints to increase the stability and healing rate of lumbar posterolateral fusions. Eleven consecutive patients with lumbosacral disc/facet joint degeneration had a posterolateral fusion augmented with 2- or 3.2-mm biodegradable rods passing perpendicularly through the center of the denuded facet joints. The patients were followed-up with RSA in supine and erect positions monthly from the 2nd to the 6th postoperative month, and again 1 year postoperatively. All seven L5-S1 fusions healed. Four cases were stable as defined by RSA within 3 months, two within 6 months, and one within 1 year. One L4-S1 fusion could not be evaluated by RSA. None of the remaining three L4-S1 fusions fully healed. In all three cases 1- to 3-mm intervertebral translations remained at 1 year. None of the 11 fusions showed any radiographic signs of osteolysis around the biodegradable rods. The promising results of this pilot study indicate that posterolateral L5-S1 fusion augmented with transarticular biodegradable rods crossing the denuded facet joints may yield rapid intervertebral stabilization and a high healing rate without any adverse rod effects. This may be due to enhanced initial fusion stabilization and/or increased ossification induced by the rods.

The safety and efficacy of the Isola Spinal Implant System for the surgical treatment of degenerative disc disease. A prospective study

STUDY DESIGN

This is a prospective study designed in consultation with and approved by the Food and Drug Administration with the purpose of determining the safety and efficacy of the Isola Spinal Implant System for the surgical treatment of patients with degenerative disc disease.

OBJECTIVES

To report the results of the degenerative disc disease group from the Isola Investigational Device Exemption study, which was done to determine whether the Isola Spinal Implant System is a safe and effective treatment.

SUMMARY OF BACKGROUND DATA

The safety and efficacy of transpedicular instrumentation as an adjunct in achieving lumbar spine fusion are still debated.

METHODS

Hospital Investigational Review Board approval of the study protocol was obtained at the 10 participating centers. One hundred twenty patients (49 men and 71 women; average age, 54 years [range, 25-83 years]) were enrolled. Clinical and radiographic follow-up evaluation was done using protocols established prospectively.

RESULTS

Of the 120 patients, 12 (10%) had device-related problems. There were two operative and four device related complications after surgery. Six other patients had their implants removed either for local pain (two) or for looseness or breakage (four). Of 118 patients eligible for follow-up evaluation at 24 months, 107 (91%) were available for study. Fusion was achieved in 97 (91%) patients. Average combined function and pain scores improved by 2.6 points (P < 0.0001). Clinical success, as measured by combining function and pain scores, was achieved in 65% of the patients by the most stringent criteria and 73% by less stringent criteria. Clinical success was significantly higher in patients who had not had previous surgery than in those who had, 77% versus 57% (P = 0.04).

CONCLUSIONS

The present study suggests that the Isola Spinal Implant System can be safely used, is an effective adjunct in the achievement of fusion, and yields an acceptable number of successful clinical outcomes, especially when considering the preponderance of previously operated patients included in this group.

Treatment of lumbar spinal stenosis by extensive unilateral decompression and contralateral autologous bone fusion: operative technique and results

A new surgical technique for the treatment of lumbar spinal stenosis features extensive unilateral decompression with undercutting of the spinous process and, to preserve stability, uses contralateral autologous bone fusion of the spinous processes, laminae, and facets. The operation was performed in 29 patients over a 19-month period ending in December of 1991. All individuals had been unresponsive to conservative treatment and presented with low-back pain in addition to signs and symptoms consistent with neurogenic claudication or radiculopathy. Nine had undergone previous lumbar decompressive surgery. The minimum and mean postoperative follow-up times were 2 and 2 1/2 years, respectively. The mean patient age was 64 years; only two patients were younger than 50 years of age. Of the patients with neurogenic claudication, 69% reported complete pain relief at follow-up review. Of those with radicular symptoms, 41% had complete relief and 23% had mild residual pain that was rated 3 or less on a pain-functionality scale of 0 to 10. For the entire sample, this surgery decreased pain from 9.2 to 3.3 (p < 0.0001) on the scale. Sixty-nine percent of patients were satisfied with surgery. Low-back pain was significantly relieved in 62% of all patients (p < 0.0001). Low-back pain relief correlated negatively with number of levels decompressed (p < 0.05). To assess fusion, follow-up flexion/extension radiographs were obtained, and no motion was detected at the surgically treated levels in any patient. The results suggest that this decompression procedure safely and successfully treats not only the radicular symptoms caused by lateral stenosis but also the neurogenic claudication symptoms associated with central stenosis. In addition, the procedure, by using contralateral autologous bone fusion along the laminae and spinous processes, can preserve stability without instrumentation.

Clinical efficacy of pedicle instrumentation and posterolateral fusion in the symptomatic degenerative lumbar spine

Eighty-five patients with degenerative lumbar spine disease and radiologic evidence of instability, all older than 50 years (mean age 63.4 years), underwent transpedicular lumbar CD-spondylodesis and posterolateral fusion between 1987 and 1992; 30 of them (mean age 60.8 years) had posterior lumbar interbody fusion (PLIF) additionally. The patients were followed up for a mean period of 32 months. Of these patients, 86% improved with respect to their pain symptoms, but only 46% showed a good to excellent overall result. Patients with fair and poor outcomes had had significantly more operations on the lumbar spine (P < 0.001), had a greater extent of preoperative lumbar kyphosis (P < 0.05), had a larger preoperative motor weakness (P < 0.05), and had less vertebral slips (P < 0.01) than patients with good to excellent outcomes. Patients treated with transpedicular spondylodesis plus PLIF did not make any better progress than those with transpedicular fusion alone. By the 6-month follow-up a significant difference in the clinical outcome was already apparent (P < 0.001), making an improvement of a then fair or poor result unlikely.