Indications for thoracic and lumbar spine fusion and trends in use

Cost Analysis of Single-Level Lumbar Fusions

STUDY DESIGN

Cost analysis of a retrospectively identified cohort of patients who had undergone primary single-level lumbar fusion at a single institution's orthopedic or neurosurgery department.

OBJECTIVE

The purpose of this article is to analyze the determinants of direct costs for single-level lumbar fusions and identify potential areas for cost reduction.

METHODS

Adult patients who underwent primary single-level lumbar fusion from fiscal years 2008 to 2012 were identified via administrative and departmental databases and were eligible for inclusion. Patients were excluded if they underwent multiple surgeries, had previous surgery at the same anatomic region, underwent corpectomy, kyphectomy, disc replacement, surgery for tumor or infection, or had incomplete cost data. Demographic data, surgical data, and direct cost data in the categories of supplies, services, room and care, and pharmacy, was collected for each patient.

RESULTS

The cohort included 532 patients. Direct costs ranged from $8286 to $73 727 (median = $21 781; mean = $22 890 ± $6323). Surgical approach was an important determinant of cost. The mean direct cost was highest for the circumferential approach and lowest for posterior instrumented spinal fusions without an interbody cage. The difference in mean direct cost between transforaminal lumbar interbody fusions, anterior lumbar interbody fusions, and lateral transpsoas fusions was not statistically significant. Surgical supplies accounted for 44% of direct costs. Spinal implants were the primary component of supply costs (84.9%). Services accounted for 38% of direct costs and were highly dependent on operative time. Comorbidities were an important contributor to variance in the cost of care as evidenced by high variance in pharmacy costs and length of stay related to their management.

CONCLUSION

The costs of spinal surgeries are highly variable. Important cost drivers in our analysis included surgical approach, implants, operating room time, and length of hospital stay. Areas of high cost and high variance offer potential targets for cost savings and quality improvements.

Trends in the surgical treatment of lumbar spine disease in the United States

BACKGROUND CONTEXT

There is a lack of agreement among spine surgeons as to the best surgical treatment modality for many degenerative lumbar diseases. Although there are many studies examining trends in spinal surgery, specific studies reporting the variations in surgical treatment in the United States for these diseases are lacking.

PURPOSE

The aim of this study was to analyze trends in lumbar spinal fusion methods for common lumbar pathologies in the United States.

STUDY DESIGN/SETTING

National insurance database review: 2004-2009.

PATIENT SAMPLE

Data is taken from United Healthcare and represents more than 25 million patients.

OUTCOME MEASURES

No outcomes were measured in this study.

METHODS

Using a private insurance database, we identified patients who underwent one of five types of instrumented single-level lumbar spinal fusion for the 10 most common primary diagnoses. Surgery rates were reviewed from 2004 to 2009 and were stratified according to patient age, patient gender, and region in the United States. Poisson regression analysis was performed to determine regional and demographic differences in treatment modality. The authors received no funds in support of this work.

RESULTS

A total of 23,986 patients met our search criteria. Of the five fusion types, posterior lumbar interbody fusion (PLIF) with posterolateral fusion (PLF) was the most common (45%), followed by PLF (19%), anterior lumbar interbody fusion (ALIF, 16%), PLIF (10%), and ALIF with PLF (9%). There was a significant increase in PLIF with PLF (p<.0001), PLIF (p<.0001), PLF (p=.012), ALIF (p<.0001), and ALIF with PLF (p<.0001) from 2004 to 2009. After controlling for gender, there were significant differences between regions for all fusion types (p<.0001). The likelihood of a posterior fusion increased with age. Anterior fusions were more common in the 30- to 49-year-old age range than in patents older than 50. For patients in age groups older than 30, there was an increased number who underwent a circumferential fusion or an ALIF (p<.022). Fusion types were significantly different between genders (p<.026). Both genders had an overall increase in the number of fusions (p<.001) over the time period studied.

CONCLUSIONS

There are large differences in the United States for surgical treatment methods for lumbar spine pathology. These differences are likely multifactorial, with both patient and surgeon traits playing a role. Illustrating these differences will hopefully lead to outcomes research to determine the indications, efficacy, and appropriateness of these surgical methods, an important step on the path toward standardization of care.

Compressed-sensing multispectral imaging of the postoperative spine

PURPOSE

To apply compressed sensing (CS) to in vivo multispectral imaging (MSI), which uses additional encoding to avoid magnetic resonance imaging (MRI) artifacts near metal, and demonstrate the feasibility of CS-MSI in postoperative spinal imaging.

MATERIALS AND METHODS

Thirteen subjects referred for spinal MRI were examined using T2-weighted MSI. A CS undersampling factor was first determined using a structural similarity index as a metric for image quality. Next, these fully sampled datasets were retrospectively undersampled using a variable-density random sampling scheme and reconstructed using an iterative soft-thresholding method. The fully and undersampled images were compared using a 5-point scale. Prospectively undersampled CS-MSI data were also acquired from two subjects to ensure that the prospective random sampling did not affect the image quality.

RESULTS

A two-fold outer reduction factor was deemed feasible for the spinal datasets. CS-MSI images were shown to be equivalent or better than the original MSI images in all categories: nerve visualization: P = 0.00018; image artifact: P = 0.00031; image quality: P = 0.0030. No alteration of image quality and T2 contrast was observed from prospectively undersampled CS-MSI.

CONCLUSION

This study shows that the inherently sparse nature of MSI data allows modest undersampling followed by CS reconstruction with no loss of diagnostic quality.

Perioperative complications and adverse events after lumbar spinal surgery: evaluation of 1012 operations at a single center

BACKGROUND

Lumbar surgery and associated complications are increasing as society is aging. However, definitions of complications after lumbar surgery have not been established and previous reports have varied in the definition of, and focus on, intraoperative or major postoperative complications. We analyzed the frequency and severity of perioperative complications and all minor adverse events in lumbar surgery at a single center.

METHODS

We retrospectively reviewed all lumbar surgery, including decompression surgery with or without fusion, at Meijo Hospital over a 10-year period. Perioperative complications and all surgery-related adverse events until 1 month postoperatively were reviewed for 1012 operations on 918 patients (average age 54 years old). The incidence of intraoperative complications was compared between junior (<10 years experience of spine surgery) and senior (≥10 years experience) surgeons.

RESULTS

Perioperative complications and adverse events occurred in 159 operations (15.7%) on 127 patients (13.8%). There were a variety of perioperative adverse events, including digestive problems. Of the 159 complications and events, 24 (2.4%) were intraoperative and 135 (13.3%) were postoperative. Incidence of intraoperative complications was not significantly higher for junior surgeons; however, the operations performed by senior surgeons were significantly more invasive. Complications were more frequent in elderly patients (p < 0.01) and in operations that were longer (p < 0.0001), had greater estimated blood loss (p < 0.0001), and involved use of spinal instrumentation (p < 0.0001). Psychotic symptoms occurred significantly more often in older patients (p < 0.001).

CONCLUSION

The absence of a relationship between the experience of the surgeon and incidence of intraoperative complications may be because of the greater effect of invasive surgery. Although age and invasiveness were associated with more perioperative adverse events, we do not conclude that major surgery should be avoided for elderly patients. In contrast, careful focus on the surgical indication and procedure is required for these patients.

Radiological Outcome of Short Segment Posterior Stabilisation and Fusion in Thoracolumbar Spine Acute Fracture

Introduction: The optimal management of thoracolumbar spine fractures remains a matter of controversy. The current literature implies that the use of short-segment pedicle screw fixation may be inappropriate because of its high reported failure rate. The purpose of this study is to report the short-term results of thoracolumbar burst and compression fractures treated with short-segment pedicle instrumentation. Materials and Methods: From 2002 to 2007, 19 patients with thoracolumbar acute traumatic fractures were instrumented with posterior short-segment pedicle screws. The patients’ case notes, operation records, preoperative and postoperative radiographs (sagittal index, anterior body compression and regional kyphosis), computed tomography scans, neurological findings (Frankel functional classification), and follow-up records up to 18 months were reviewed. Results: A statistically significant difference was found between the patients’ preoperative, postoperative and follow-up sagittal index, anterior body compression and regional kyphosis measurement. One case resulted in screw pedicle screw pullout and subsequently, kyphotic deformity. The patient underwent revision surgery to long-segment posterior instrumentation and fusion. None of the patients showed an increase in neurological defi cit. Conclusion: In conclusion, the short-term follow-up results suggest a favourable outcome for short-segment instrumentation. Load shearing classification is essential for the selection of patient for short-segment instrumentation. However, the long-term follow-up evaluation will be needed to verify our findings. Key words: Kyphoytic angle, Radiological outcome, Short segment posterior fixation, Thoracolumbar spine fractures

No difference in health-related quality of life in hip osteoarthritis compared to degenerative lumbar instability at pre- and 1-year postoperatively: a prospective study of 101 patients

BACKGROUND

Total hip replacement (THR) is a very successful and refined surgical procedure when compared to crude bony fusion in degenerative lumbar segmental instability (LF). We compared the pre- and postoperative health-related quality of life status of THR and LF patients.

PATIENTS AND METHODS

We prospectively studied 51 THR patients and 50 LF patients. The outcome parameters were SF-36 and Oswestry Disability Index (ODI), measured preoperatively and at 1 year postoperatively. The status of the patients was compared to that of an age-matched healthy control group.

RESULTS

The preoperative SF-36 and ODI scores were similar between the groups, except for the subscale role emotional. One year postoperatively, only the differences in 3 subscales (physical functioning, role physical, and role emotional) and in the standardized physical component reached statistical significance; the THR-patients scored worse than the LF-patients. The improvements in SF-36 and ODI reached statistical significance in both groups.

INTERPRETATION

The differences in quality of life between the THR and LF patients were similar pre- and postoperatively. The quality of life of both cohorts improved considerably and significantly after the treatment, but they remained at a level significantly below that of a general age-matched population.

Unstable upper and middle thoracic fractures. Preliminary experience with a posterior transpedicular correction-fixation technique

A number of conservative and operative approaches have been described for the treatment of unstable traumatic upper and middle thoracic fractures. The advantage of surgical correction and fixation/fusion lies in its potential to restore sagittal and coronal alignment, thereby indirectly decompressing the spinal cord. A consecutive series of 8 patients with unstable traumatic upper and middle thoracic fractures is reviewed. In all patients, polyaxial pedicle screws were inserted bilaterally into the two levels above and below the fracture. Rods that were less contoured ("undercontoured") than the regional hyperkyphosis at the injured level, were anchored to the caudal four screws. The cranial four screws, with the vertebrae to which they were inserted, were then progressively pulled posteriorly onto the undercontoured rods with rod reducers, thus correcting the hyperkyphosis and anterolisthesis. The mean follow-up was 15 months. The mean regional kyphosis was 23 degrees preoperatively, 17 degrees postoperatively and 18 degrees at follow-up. The mean anterolisthesis was 8 mm preoperatively, 1 mm postoperatively and 1 mm at follow-up. No hardware failure occurred. Five patients with complete spinal cord injury at presentation made no neurological recovery, two patients with incomplete spinal cord injury initially (ASIA B), recovered substantially (to ASIA D), and the patients who were neurologically intact at presentation remained so.

Why a mechanical disc?

Low back pain secondary to degenerative disc disease is an overwhelming and growing problem in the United States and Western countries. Most degenerative disc disease can be treated nonoperatively. There are, however, substantial numbers of patients who have not benefited from exhaustive nonoperative treatments and subsequently seek surgical solutions to their incapacitating back pain. Lumbar fusion for back pain and/or leg pain associated with degenerative disc disease is considered the gold standard by which other treatments are judged. A challenge to spinal fusion for degenerative disc disease is now being offered in the form of the artificial disc. The implantation of an artificial lumbar disc allows for maintenance or restoration of physiologic movement at affected segments. A major long-term complication of spinal fusion is degeneration of a disc adjacent to the fused segments. Theoretically, the maintenance of motion could minimize development of adjacent disc degeneration as seen with spinal fusion. It is interesting to note that fusion of the hip or knee is not considered a primary procedure, but fusion is a primary procedure for the lumbar spine. Four artificial lumbar discs are discussed in this article. Early results are promising in terms of clinical results and movement, but long-term follow-up clinical trials must be done in order to gain an accurate comparison with spinal fusion. Trials are currently ongoing. The clinical results up to now and the potential for maintaining lumbar mobility throughout life warrant continuation of this surgical procedure.

Threaded cortical bone dowels in lumbosacral arthrodesis: a review

Lumbar fusion is a common spinal surgery, for which numerous devices have been developed to aid in segment stabilization. A threaded cortical bone dowel is a machined and processed bone allograft which is one such development. Threaded cortical bone dowels are attractive because of their osteoconductive nature and the opportunity to load them with osteogenic morselized bone autograft or osteoinductive growth factors, such as bone morphogenetic proteins. Although threaded cortical bone dowels have been in clinical use for more than 5 years, they have not been the subject of a comprehensive review. The current article covers the history, preparation, uses, safety, and efficacy of threaded cortical bone dowels in lumbosacral interbody fusion.

National and regional rates and variation of cervical discectomy with and without anterior fusion, 1990-1999

STUDY DESIGN

A national hospitalization database was used to determine rates and trends in the treatment of cervical disc disease.

OBJECTIVE

To examine the temporal and geographic variations in hospitalizations and surgical procedures for cervical disc disease.

SUMMARY OF BACKGROUND DATA

Studies of spinal surgery during the 1980s showed significant increases in the rates for all procedures, particularly those involving fusion. The management of cervical disc disease continues to be controversial.

METHODS

Data from the National Hospital Discharge Survey from 1990 through 1999 were analyzed. Records were selected and categorized according to an algorithm of International Classification of Diseases (ICD-9) procedure and diagnosis codes.

RESULTS

During the study period, the rate of hospitalization for surgical and nonsurgical treatment of cervical disc disease did not increase significantly. There was, however, a statistically significant increase in the proportion of hospitalizations for the surgical treatment of cervical disc disease that included a fusion procedure. There also was significant geographic variation in the rate of fusion procedures, with the South having the highest rate.

CONCLUSIONS

Although the rate of surgery for cervical disc disease did not increase significantly during the 1990s, the rate of fusion procedures did rise significantly.

The treatment of unstable thoracic spine fractures with transpedicular screw instrumentation: a 3-year consecutive series

STUDY DESIGN

The treatment of unstable thoracic spine fractures remains controversial. Theoretical biomechanical advantages of transpedicular screw fixation include three-column control of vertebral segments and fixation of a vertebral segment in the absence of intact posterior elements. Additionally, pedicle screw constructs may obviate the need for neural canal dissection and potential neural element impingement by intracanal instrumentation. A 3-year consecutive series was performed to evaluate the use of transpedicular screw fixation in the treatment of unstable thoracic spine injuries.

OBJECTIVE

This study was performed to evaluate the efficacy of transpedicular screw fixation in the upper, middle, and lower thoracic spine.

SUMMARY OF BACKGROUND DATA

The use of rod/hook and rod/wiring techniques has been evaluated in the treatment of thoracic spine injuries. To date, a study evaluating the safety and efficacy of pedicle screw instrumentation in the upper, middle, and lower thoracic spine has not been reported.

METHODS

Thirty-two patients with 79 individual vertebral injury levels (T2-L1) treated with transpedicular spinal stabilization and bone fusion were evaluated during a 3-year consecutive series from 1998 to 2001. Patient charts, operative reports, preoperative and postoperative radiographs, computed tomography scans, and postoperative follow-up examinations and radiographs were reviewed from the time of surgery to final follow-up assessment. Radiographic measurements included: sagittal index, Gardner segmental kyphotic deformity, and compression percentage.

RESULTS

A total of 252 pedicle screws were placed, of which 222 were placed in segments T2-L1. Clinical examination and plain radiographs were used to determine the presence of a solid fusion. Fracture healing and radiographic stabilization occurred at an average of 4.8 months after the initial operation. There were no reported cases of hardware failure, loss of reduction, or painful hardware removal. Two hundred fifty-two transpedicular screws were successfully placed without intraoperative complications. The mean preoperative sagittal index was 13.9 degrees, whereas the mean follow-up was 5.25 degrees (P < 0.001). The mean final correction of sagittal index achieved was 8.65 degrees, or a 62.2% improvement. The mean Gardner segmental kyphotic angle was 15.9 degrees, whereas the mean follow-up angle was 10.6 degrees (P < 0.0005). The mean compression percentage was 35.4, and at follow-up was 27.4 (P < 0.07).

CONCLUSIONS

In carefully selected instances, pedicle screw fixation of upper, middle, and lower thoracic and upper thoracolumbar spinal injuries is a reliable and safe method of posterior spinal stabilization. Transpedicular screw fixation may offer superior three-column control in the absence of posterior element integrity and obviates the need for intracanal placement of hardware. Transpedicular instrumentation provides rigid fixation for upper, middle, and lower unstable thoracic spine injuries and produces early pain-free fusion results. These results provide evidence that with appropriate preoperative radiographic evaluation of pedicular size and orientation using computed tomography as well as radiograph assessment, transpedicular instrumentation is a safe and effective alternative in the treatment of unstable thoracic (T2-L1) spinal injuries.

Intraoperative antepulsion of a fusion cage in posterior lumbar interbody fusion: a case report and review of the literature

STUDY DESIGN

A case of intraoperative anterior migration into the abdominal cavity of a titanium fusion cage in the course of posterior lumbar interbody fusion.

OBJECTIVES

To explain the importance of a proper introduction of the fusion cages in the vertebral space and the necessity of intraoperative fluoroscopy study in both planes, frontal and lateral, respectively, to confirm the proper position of the implants. A potential serious complication of fusion cage instrumentation and the limited literature on this subject are reviewed.

SUMMARY OF BACKGROUND DATA

Early reports regarding fusion cage instrumentation have been encouraging. However, the potential benefits are better defined than the potential complications.

METHODS

A patient had anterior migration of a fusion cage intraoperatively in the course of posterior lumbar interbody fusion. One day later, the patient underwent surgical laparotomy to extract the migrated implant and a repeat posterior procedure that included bilateral posterior fusion with insertion of pedicle instrumentation.

RESULTS

One year after the second operation, the patient remains pain-free, and no abdominal lesions or neurologic deficits were observed.

CONCLUSIONS

The various types of spinal fusion operations are associated with specific complications. A through knowledge of the procedures and possible complications, as well as meticulous surgical technique, can help minimize these. Once complications do occur, prompt recognition and treatment should minimize the long-term sequelae.

The clinical usefulness of intraoperative spinal stiffness measurements

STUDY DESIGN

Determination of clinical results at least 2 years after lumbar spine surgery during which spinal stiffness measurements were made.

OBJECTIVES

To determine whether spine stiffness is predictive of clinical results after lumbar spine surgery for spinal stenosis, disc herniation, or degenerative spondylolisthesis.

SUMMARY OF BACKGROUND DATA

The implied clinical wisdom is that instability of the spine portends a poor prognosis for relief of back pain after surgery in the absence of a fusion. The possibility that an objective measure of lumbar spinal motion segment unit stiffness could aid the surgeon in predicting satisfaction with treatment was considered.

METHODS

A total of 298 patients were measured intraoperatively with the spinal stiffness gauge to determine motion segment stiffness. Intraoperative spinal stiffness was analyzed to determine the influence of this measurement on clinical results.

RESULTS

Statistical analysis revealed that stiffness measurements did not correlate with clinical results of surgery. Patients with loose motion segment units before decompression did not demonstrate a significantly different level of satisfaction with surgical results a minimum of 2 years after surgery, whether they were fused or not fused. Based on stiffness measurements, a diagnosis of herniated nucleus pulposus or degenerative spondylolisthesis was indicative of a more unstable spine than a diagnosis of spinal stenosis.

CONCLUSIONS

Intraoperative spinal stiffness measurements did not predict clinical results after lumbar spine surgery.

2001 Volvo Award Winner in Clinical Studies: Lumbar fusion versus nonsurgical treatment for chronic low back pain: a multicenter randomized controlled trial from the Swedish Lumbar Spine Study Group

STUDY DESIGN

A randomized controlled multicenter study with a 2-year follow-up by an independent observer.

OBJECTIVES

To determine whether fusion of the lower lumbar spine could reduce pain and diminish disability more effectively when compared with nonsurgical treatment in patients with severe chronic low back pain (CLBP).

SUMMARY OF BACKGROUND DATA

The reported results after fusion surgery on patients with CLBP vary considerably, and the evidence of treatment efficacy is weak in the absence of randomized controlled studies.

PATIENTS AND METHODS

A total of 294 patients referred to 19 spinal centers from 1992 through 1998 were randomized blindly into four treatment groups. Patients aged 25-65 years with CLBP for at least 2 years and with radiologic evidence of disc degeneration at L4-L5, L5-S1, or both were eligible to participate in the study. The surgical group (n=222) included three different fusion techniques, not analyzed separately in this study. Patients in the nonsurgical group (n=72) were treated with different kinds of physical therapy. The surgical group comprised 49.5% men, and the mean age was 43 years. The corresponding figures for the nonsurgical group were 48.6% and 44 years. The patients had suffered from low back pain for a mean of 7.8 and 8.5 years and been on sick leave due to back pain for a mean of 3.2 and 2.9 years, respectively. The Visual Analogue Scale (VAS) was used to measure pain. The Oswestry Low Back Pain Questionnaire, the Million Score and the General Function Score (GFS) were used to measure disability. The Zung Depression Scale was used to measure depressive symptoms. The overall result was assessed by the patient and by an independent observer. Records from the Swedish Social Insurance were used to evaluate work disability. Patients who changed groups were included in the analyses of significance according to the intention-to-treat principle.

RESULTS

At the 2-year follow-up 289 of 294 (98%) patients, including 25 who had changed groups, were examined. Back pain was reduced in the surgical group by 33% (64 to 43), compared with 7% (63 to 58) in the nonsurgical group (P=0.0002). Pain improved most during the first 6 months and then gradually deteriorated. Disability according to Oswestry was reduced by 25% (47 to 36) compared with 6% (48 to 46) among nonsurgical patients (P=0.015), according to Million by 28% (64 to 46) compared with 8% (66 to 60) (P=0.004), and accordingtoGFS by 31% (49 to 34) compared with 4% (48 to 46) (P=0.005). The depressive symptoms, according to Zung, were reduced by 20% (39 to 31) in the surgical group compared with 7% (39 to 36) in the nonsurgical group (P=0.123). In the surgical group 63% (122/195) rated themselves as "much better" or "better" compared with 29% (18/62) in the nonsurgical group (P<0.0001). The "net back to work rate" was significantly in favor of surgical treatment, or 36% vs. 13% (P=0.002). The early complication rate in the surgical group was 17%.

CONCLUSION

Lumbar fusion in a well-informed and selected group of patients with severe CLBP can diminish pain and decrease disability more efficiently than commonly used nonsurgical treatment.