Indications for instrumentation in degenerative lumbar spinal disorders

The Lumbosacral Fractional Curve in Adult Degenerative Scoliosis

Spine surgeons are often faced with a profoundly difficult challenge in surgically treating adult degenerative scoliosis. Deformity correction surgery is complicated by the difficulty in offering extensive surgical corrections to the elderly, complication-prone population it commonly affects. As spine surgeons attempt to offer minimally invasive solutions to this disease process, the need for fusion of the fractional curve at L4, L5, and S1 may be discounted. A treatment strategy to identify, address, and treat the fractional curve with either open or minimally invasive techniques can lead to improved patient outcomes and decrease revision rates in this complicated pathologic process.

Short-Segment versus Long-Segment Spinal Fusion Constructs for the Treatment of Adult Degenerative Scoliosis: A Comparison of Clinical Outcomes

OBJECTIVE

To compare clinical outcomes of patients diagnosed with degenerative scoliosis undergoing short-segment versus long-segment spinal fusion.

METHODS

A retrospective cohort study was conducted of patients with degenerative thoracolumbar scoliosis undergoing elective spinal fusion at a single academic medical center. Cohorts were divided into short-segment (<3) or long-segment (≥3) groups.

RESULTS

A total of 197 patients (122 short, 75 long) were included. Patients undergoing short-segment fusion more frequently presented with radiculopathy (P < 0.001) and had greater baseline visual analog scale (VAS) leg scores (P < 0.001). Patients with long-segment fusions had longer hospital length of stay (short, 3.82 ± 2.98 vs. long, 7.40 ± 6.85 days; P < 0.001), lower home discharge rates (short, 80.3% vs. long, 51.8; P = 0.003), higher revision surgery rates (short, 10.77% vs. long, 25.3%; P = 0.012), and greater percentage curve correction (short, 37.3% ± 25.9% vs. long, 45.1% ± 23.9%; P = 0.048). No significant differences were noted in postoperative complication rates (short, 1.64% vs. long, 5.33%; P = 0.143). At 1 year, patients with long fusions had worse ΔOswestry Disability Index (ODI) (P = 0.024), ΔVAS leg score (P = 0.002), and VAS leg minimum clinically important difference % (P = 0.003). Multivariate regression found that short-segment fusions were associated with greater improvements in ODI (P = 0.029), Physical Component Summary-12 (P = 0.024), and VAS leg score at 1 year (P = 0.002).

CONCLUSIONS

Patients undergoing short-segment fusions more frequently presented with radiculopathy and had higher preoperative VAS leg scores compared with those receiving long constructs. Short-construct fusions in appropriately selected patients may provide satisfactory improvements in patient-reported outcome measures, particularly ΔODI and ΔVAS leg score, and mitigate hospital length of stay, revision surgery rates, and nonhome discharge.

Long-term Outcomes after Microsurgical Decompression of Lumbar Foraminal Stenosis and Adverse Effects of Preoperative Scoliosis: A Prospective Cohort Study

Lumbar foraminal stenosis is a common disorder, with surgical treatment varying from simple decompression to interbody fusion. It is often associated with degenerative lumbar scoliosis, but the effects of scoliosis on outcomes are unclear. The objectives of this study were to clarify long-term outcomes after microsurgical decompression of lumbar foraminal stenosis through Wiltse’s approach and to determine the effects of scoliosis on these outcomes. A total of 86 consecutive patients with lumbar foraminal stenosis were prospectively followed after microsurgical decompression. They were categorized in multiple subcohorts with follow-up durations ranging from 6 months to 5 years. Outcomes were assessed using the Short Form 36 questionnaire (average physical scores and bodily pain scores). Local Cobb angle of the operative segment was measured preoperatively, and its effects on outcomes were analyzed. Average physical scores improved significantly from 33.8 (95% confidence interval [CI]: 29.1–38.5) preoperatively to 59.5 (95% CI: 54.6–64.3) at 6 months postoperatively and remained improved for 5 years. Bodily pain scores improved significantly from 23.7 (95% CI: 18.7–28.6) preoperatively to 56.3 (95% CI: 51.2–61.6) at 6 months postoperatively and remained improved for 5 years. Patients with preoperative scoliosis (local Cobb angle >10 degrees) had poorer outcomes: average physical scores were worse by 9.6 points (p = 0.07) and bodily pain scores were worse by 12.1 points (p = 0.02), compared with patients without scoliosis (local Cobb angle ≤10 degrees). Microsurgical foraminal decompression produced overall excellent outcomes in patients with lumbar foraminal stenosis. Preoperative scoliosis attenuated these beneficial effects.

Degenerative scoliosis of the spine: diagnosis, classification and surgical approach in older patients

Adult scoliosis is a deformity of the spine with an angle of more than 10 (according to Cobb) in people with a fully formed bone system. Due to the aging of the population, improvement of surgical techniques, creation of new implants and progress in anesthetic aids, the problem of degenerative scoliosis has been more and more frequently considered from the viewpoint of a surgical approach. There are many theories about the factors that contribute to the formation of degenerative scoliosis. The conservative therapy of degenerative scoliosis includes non-steroidal anti-inflammatory drugs, bracing, epidural and paravertebral injections with glucocorticosteroids and physical therapy. In case the conservative therapy is ineffective and there is a significant decrease in the quality of life, the issue of the surgical intervention is raised individually for each patient. Currently, the role and the volume of the surgical intervention in individuals with this pathology remains debatable. The choice of a surgical technique depends on a thorough assessment of clinical symptoms, neurological status, data of instrumental methods and a mandatory estimation of the parameters of the global vertebral-pelvic balance. Therefore, in this article, we pay special attention to the surgical algorithms based on the choice of the decompression type and the fusion length. We describe the generally accepted criteria for selecting the level of spondylosynthesis. Special attention is paid to the risk factors of the surgical treatment, as well as associated complications.

The Hip-Spine Challenge

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The proper diagnosis and treatment of patients with concurrent hip and spine pathological processes can be challenging because of the substantial overlap in symptomatology.

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There is no consensus on which pathological condition should be addressed first.

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Factors such as advanced spinal degeneration, deformity, and prior fusion alter the biomechanics of the spinopelvic unit. Attention should be paid to recognizing these issues during the work-up for a total hip arthroplasty as they can result in an increased risk of dislocation.

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In patients with concurrent spine and hip degeneration, the surgeon must pay close attention to appropriate implant positioning and have consideration for implants with enhanced stability to minimize the risk of dislocation.

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A proper understanding of sagittal balance and restoration of this balance is integral to improving patient outcomes following spinal surgery.

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The advent of new imaging modalities, increased awareness of spinopelvic mobility, as well as a better understanding of sagittal alignment will hopefully improve our treatment of patients with hip-spine syndrome.

Does sagittal imbalance impact the surgical outcomes of short-segment fusion for lumbar spinal stenosis associated with degenerative lumbar scoliosis?

BACKGROUND

The degenerative lumbar scoliosis (DLS) patients who mainly complained about neurogenic claudication due to spinal canal stenosis are well-indicated for short segment fusion (SSF) at the affecting levels. However, it is unclear whether we should consider global sagittal balance or not. The aim of this study was to evaluate the impact of sagittal balance on the surgical outcomes of degenerative lumbar scoliosis (DLS) patients who underwent SSF.

METHODS

We retrospectively reviewed 70 DLS patients who underwent SSF (less than 3 levels) and could be followed for at least 2 years. The PI-LL, PT, SVA, and T1 pelvic angle (TPA) were measured using standing whole spine X-rays preoperatively (PreO) and at final follow-up (FFU). Surgical outcomes were assessed with the improvement in Japanese Orthopaedic Association score (JOAs) for low back pain (LBP), and the level of LBP was measured using the visual analogue scale (LBP-VAS). We analysed the relationships between the radiographic parameters and the surgical outcomes.

RESULTS

We divided the patients into the three groups (poor/fair/good) based on the JOAs. The analysis with the Jonckheere-Terpstra trend test indicated that the following radiographic parameters had a significant trend with surgical outcomes in each group: (poor/fair/good; p value); PreO PI-LL (26/20/17°; P = 0.04), SVA (46/75/35.5 mm; P = 0.02), TPA (28/27/23°; p = 0.04), FFU PI-LL (33/25/8.5°; P = 0.004), SVA (93/90.5/32.5 mm; P = 0.001), and TPA (33/29/25°; P = 0.007). Additionally, LBP-VAS had a significant correlation between the three groups at final follow-up (P = 0.004). There were significant correlations between improvement in JOAs and PI-LL, SVA, and TPA both PreO and at FFU (P < 0.05).

CONCLUSIONS

Sagittal spinal imbalance and spinopelvic malalignment significantly impact the surgical outcomes of SSF for DLS. Preoperative evaluation of spinopelvic alignment and sagittal balance is of critical importance when SSF are performed for DLS patients.

Outcomes of Short Fusion versus Long Fusion for Adult Degenerative Scoliosis: A Systematic Review and Meta-analysis

The objective of this study was to evaluate differences in clinical and radiographic outcomes between short (<3 levels) and long (≥3 levels) fusions in the setting of degenerative lumbar scoliosis. A literature search was performed from six electronic databases. The key terms of "degenerative scoliosis" OR "lumbar scoliosis" AND "fusion" were combined and used as MeSH subheadings. From relevant studies identified, demographic data, complication rates, Oswestry Disability Index (ODI), and radiographic parameters were extracted and the data was pooled and analyzed. Long fusion was associated with comparable overall complication rates to short fusion (17% vs 14%, P = 0.20). There was a significant difference in the incidence of pulmonary complications when comparing short versus long fusion (0.42% vs 2.70%; P = 0.02). No significant difference was found in terms of motor, sensory complications, infections, construct-related or cardiac complications, pseudoarthrosis, dural tears, cerebrospinal fluid (CSF) leak, or urinary retention. A longer fusion was associated with a greater reduction in coronal Cobb angle and increases in lumbar lordosis, but both findings failed to achieve statistical significance. The ODI was comparable across both cohorts. If shorter fusion lengths are clinically indicated, they should be used instead of longer fusion lengths to reduce perioperative time, costs, and some other complications. However, there are no statistically significant differences in terms of radiographically measurable restoration associated with a short or long fusion.

Optimal Pelvic Incidence Minus Lumbar Lordosis Mismatch after Long Posterior Instrumentation and Fusion for Adult Degenerative Scoliosis

OBJECTIVE

To evaluate the influence of Scoliosis Research Society (SRS)-Schwab sagittal modifiers of pelvic incidence minus lumbar lordosis mismatch (PI-LL) on clinical outcomes for adult degenerative scoliosis (ADS) after long posterior instrumentation and fusion.

METHODS

This was a single-institute, retrospective study. From 2012 to 2014, 44 patients with ADS who underwent posterior instrumentation and fusion treatment were reviewed. Radiological evaluations were investigated by standing whole spine (posteroanterior and lateral views) X-ray and all radiological measurements, including Cobb's angle, LL, PI, and the grading of vertebral rotation, were performed by two experienced surgeons who were blind to the operations. The patients were divided into three groups based on postoperative PI-LL and the classification of the SRS-Schwab: 0 grade PI-LL (<10°, n = 13); + grade PI-LL (10°-20°, n = 19); and ++ grade PI-LL (>20°, n = 12). The clinical outcomes were assessed according to Japanese Orthopaedic Association (JOA) score, Oswestry Disability Index (ODI), Visual Analog Scale (VAS), Lumbar Stiffness Disability Index (LSDI), and complications. Other characteristic data of patients were also collected, including intraoperative blood loss, operative time, length of hospital stay, complications, number of fusion levels, and number of decompressions.

RESULTS

The mean operative time, blood loss, and hospital stay were 284.5 ± 30.2 min, 1040.5 ± 1207.6 mL, and 14.5 ± 1.9 day. At the last follow-up (2.6 ± 0.6 years), the radiological and functional parameters, except the grading of vertebral rotation, were all significantly improved in comparison with preoperative results (P < 0.05), but it was obvious that an ideal PI-LL (≤10°) was not achieved in some patients. Significant differences were only observed among the three groups in the ODI and LSDI. Patients with + grade PI-LL seemed to have the best surgical outcome compared to those with 0 and ++ grade PI-LL, with the lowest ODI score (+ grade vs 0 grade, 17.3 ± 4.9 vs 26.0 ± 5.4; + grade vs ++ grade, 17.3 ± 4.9 vs 32.4 ± 7.3; P < 0.05) and lower LSDI (+ grade vs 0 grade, 1.6 ± 1.0 vs 3.5 ± 0.5, P < 0.05; + grade vs ++ grade, 1.6 ± 1.0 vs 0.6 ± 0.5, P > 0.05). A Pearson correlation analysis further demonstrated that LSDI was negatively associated with PI-LL. Furthermore, the incidence rate of postoperative complications was lower in patients with + grade PI-LL (1/19, 5.26%) than that in patients with 0 (2/13, 15.4%) and ++ grade PI-LL (3/12, 25%).

CONCLUSION

Our present study suggest that the ideal PI-LL may be between 10° and 20° in ADS patients after long posterior instrumentation and fusion.

The surgical outcome of decompression alone versus decompression with limited fusion for degenerative lumbar scoliosis

OBJECTIVE The aim of this study was to assess the usefulness of radiological parameters for surgical decision-making in patients with degenerative lumbar scoliosis (DLS) by comparing the clinical and radiological results after decompression or decompression and fusion surgery. METHODS The authors prospectively planned surgical treatment for 298 patients with degenerative lumbar disease between September 2005 and March 2013. The surgical method used at their institution to address intervertebral instability is precisely defined based on radiological parameters. Among 64 patients with a Cobb angle ranging from 10° to 25°, 57 patients who underwent follow-up for more than 2 years postoperatively were evaluated. These patients were divided into 2 groups: those in the decompression group underwent decompression alone (n = 25), and those in the fusion group underwent decompression and short segmental fusion (n = 32). Surgical outcomes were reviewed, including preoperative and postoperative Cobb angles, lumbar lordosis based on radiological parameters, and Japanese Orthopaedic Association (JOA) scores. RESULTS The JOA scores of the decompression group and fusion group improved from 5.9 ± 1.6 to 10.0 ± 2.8 and from 7.2 ± 2.0 to 11.3 ± 2.8, respectively, which was not significantly different between the groups. At the final follow-up, the postoperative Cobb angle in the decompression group changed from 14° ± 2.9° to 14.3° ± 6.4° and remained stable, while the Cobb angle in the fusion group decreased from 14.8° ± 4.0° to 10.0° ± 8.5° after surgery. CONCLUSIONS The patients in both groups demonstrated improved JOA scores and preserved Cobb angles after surgery. The improvement in JOA scores and preservation of Cobb angles in both groups show that the evaluation of spinal instability using radiological parameters is appropriate for surgical decision-making.

Radiographic Risk Factors of Reoperation Following Minimally Invasive Decompression for Lumbar Canal Stenosis Associated With Degenerative Scoliosis and Spondylolisthesis

STUDY DESIGN

Prospective cohort study.

OBJECTIVE

Microsurgical bilateral decompression via a unilateral approach (MBDU), a minimally invasive surgical (MIS) decompression method, has been performed for numerous degenerative lumbar diseases, including degenerative lumbar scoliosis (DLS) or degenerative spondylolisthesis (DS), at our institution. In this study, we evaluated the appropriateness of MBDU for DLS or DS patients.

METHODS

A total of 207 patients treated by MBDU were included (88 women and 119 men; mean age, 70 [40-86] years). Thirty-seven cases were diagnosed as DLS (group A), 51 as DS (group B), and 119 as lumbar canal stenosis (group C). Patient clinical status assessed by JOA score was evaluated preoperatively and 2 years postoperatively. We evaluated the prevalence of cases that required reoperation among the groups and the radiographic risk factors related to reoperation.

RESULTS

There was no significant difference in recovery ratios of JOA scores among the groups. Reoperation after MBDU was needed in 13 cases (6.3%); the revision rate did not significantly differ among the groups. Reoperation was associated with poor clinical status, low visual analog scale score for low back pain, and low SF-36 mental component summary score. Reoperation was significantly associated with preoperative scoliotic disc wedging with Cobb's angle ≥3° in L4-5 (odds ratio = 9.88) and lateral listhesis (odds ratio = 5.22 [total], 12.9 [L4-5]).

CONCLUSIONS

When we are careful to indicate decompression for patients with these risk factors related to reoperation, MIS decompression alone can successfully improve DLS patients with a Cobb's angle of ≤20° or DS patients.

Applications of the scoliosis width-to-length ratio for guiding selection of the surgical approaches of degenerative lumbar scoliosis

Background

There does not exist a comprehensive parameter for guiding selection of short or long segment fusion for degenerative lumbar scoliosis (DLS). The aim of our study was to investigate the applications of the width-to-length ratio in guiding selection of the surgical approaches for DLS.

Methods

A retrospective analysis was performed of 142 patients with DLS who underwent operative treatments from July 2000 to January 2012. The scoliosis width-to-length ratios were measured and used as a grouping criterion of surgical approaches. The Oswestry disability index (ODI) was used to evaluate the clinical outcomes. Radiological parameters such as Cobb’s angle of main curve, Cobb’s angle of compensatory curve were all measured.

Results

For patients with width-to-length ratio less than 0.36, the short segment group had better short-term postoperative outcomes with regard to Cobb’s angle of main curve, Cobb’s angle of compensatory curve and ODI scores compared to the long segment group. However, for patients with width-to-length ratio greater than 0.36, the postoperative outcomes for the long segment group were better compared to the short segment group.

Conclusions

The scoliosis width-to-length ratio can provide a comprehensive preoperative assessment of the severity of the DLS and guiding selection of a therapeutic treatment regimen. Further studies with a larger number of samples and longer term of follow up are warranted.

Surgical treatment of adult degenerative scoliosis

The rapid increase of elderly population has resulted in increased prevalence of adult scoliosis. Adult scoliosis is divided into adult idiopathic scoliosis and adult degenerative scoliosis. These two types of scoliosis vary in patient age, curve pattern and clinical symptoms, which necessitate different surgical indications and options. Back pain and deformity are major indications for surgery in adult idiopathic scoliosis, whereas radiating pain to the legs due to foraminal stenosis is what often requires surgery in adult degenerative scoliosis. When selecting a surgical method, major symptoms and underlying medical diseases should be carefully evaluated, not only to relieve symptoms but also to minimize postoperative complications. Surgical options for adult degenerative scoliosis include: decompression alone; decompression and limited short fusion; and decompression coupled with long fusion and correction of deformity. Decompression and limited short fusion can be applied to patients with a small Cobb's angle and normal sagittal imbalance. For those with a large Cobb's angle and positive sagittal imbalance, long fusion with correction of deformity is required. When long fusion is applied, a careful decision regarding the extent of fusion level should be made when selecting L5 or S1 as the distal fusion level and T10 or the thoracolumbar junction as the proximal fusion level. For the fusion extending to the sacrum, restoration of sagittal balance and rigid fixation with additional iliac screws should be considered. Any surgical procedures for adult degenerative scoliosis are known to have relatively high occurrences of complications; therefore, risks and benefits should be meticulously considered before selecting a surgical procedure.

Degenerative lumbar scoliosis in elderly patients: dynamic stabilization without fusion versus posterior instrumented fusion

BACKGROUND CONTEXT

Posterolateral fusion with pedicle screw instrumentation is currently the most widely accepted technique for degenerative lumbar scoliosis in elderly patients. However, a high incidence of complications has been reported in most series. Dynamic stabilization without fusion in patients older than 60 years has not previously been compared with the use of posterior fusion in degenerative lumbar scoliosis.

PURPOSE

To compare dynamic stabilization without fusion and posterior instrumented fusion in the treatment of degenerative lumbar scoliosis in elderly patients, in terms of perioperative findings, clinical outcomes, and adverse events.

STUDY DESIGN

A retrospective study.

PATIENT SAMPLE

Fifty-seven elderly patients were included. There were 45 women (78%) and 12 men (22%) with a mean age of 68.1 years (range, 61-78 years). All patients had degenerative de novo lumbar scoliosis, associated with vertebral canal stenosis in 51 cases (89.4%) and degenerative spondylolisthesis in 24 patients (42.1%).

OUTCOME MEASURES

Clinical (Oswestry Disability Index, visual analog scale, Roland-Morris Disability Questionnaire) and radiological (scoliosis and lordosis corrections) outcomes as well as incidence of complications.

METHODS

Patients were divided into two groups: 32 patients (dynamic group) had dynamic stabilization without fusion and 25 patients (fusion group) underwent posterior instrumented fusion. All the patients' medical records and X-rays were reviewed. Preoperative, postoperative, and follow-up questionnaires were obtained to evaluate clinical outcomes.

RESULTS

At an average follow-up of 64 months (range, 42-90 months), clinical results improved similarly in both groups of patients. Statistically superior scoliosis and final lordosis corrections were achieved with posterior fusion (56.9% vs. 37.3% and -46.8° vs. -35.8°, respectively). However, in the dynamic group, incidence of overall complications was lower (25% vs. 44%), and fewer patients required revision surgery (6.2% vs. 16%). Furthermore, lower average values of operative duration (190 vs. 240 minutes) and blood loss (950 vs. 1,400 cc) were observed in the dynamic group than in the fusion group.

CONCLUSIONS

In elderly patients with degenerative lumbar scoliosis, pedicle screw-based dynamic stabilization was less invasive with shorter operative duration, less blood loss, and lower adverse event rates than instrumented posterior fusion. Scoliosis curve reduction and lumbar lordosis were superior after fusion; however, dynamic stabilization achieved satisfying values of both these parameters, and these results were stable after an average follow-up of more than 5 years. Furthermore, there was no difference between the two techniques in terms of functional clinical outcomes at the last follow-up.

Curve progression after decompression surgery in patients with mild degenerative scoliosis

OBJECT

The authors undertook this study to evaluate curve progression, risk factors for curve progression, and outcomes after decompression surgery in patients with degenerative lumbar scoliosis with minimal to moderate curvature.

METHODS

Of 852 patients with lumbar canal stenosis treated by posterior decompression surgery, 50 patients had a lumbar curve greater than 10° at final follow-up. These patients were divided into 2 groups according to curve progression during the follow-up period: the P group (11 patients), with a curve progression of more than 5°, and the NP group (39 patients), with a curve progression of 5° or less. The authors compared preoperative parameters in these 2 groups to elucidate risk factors associated with curve progression and other surgical outcomes.

RESULTS

The average lumbar curve progression in the total group of 50 patients was 3.4° ± 3.9° (range -2.0° to 22.0°). In the P group the average curve progression was 8.5°, and in the NP group it was 2.0°. Multivariate logistic regression analysis showed no significant association between curve progression and any of the potential risk factors evaluated (including curve magnitude, decompression method, and degenerative intervertebral disc changes). Spur formation, evaluated with the Nathan classification at the concave side of the curve, tended to be greater in the P group, although the difference was not statistically significant. There was no significant difference in revision surgery rate, and none of the patients required arthrodesis due to curve progression. Clinical outcomes, evaluated with the Japanese Orthopaedic Association Back Pain Evaluation Questionnaire and the Scoliosis Research Society 22-question questionnaire, were also similar in the 2 groups.

CONCLUSIONS

Surgical outcomes did not deteriorate in the P group. While curve progression after decompression surgery could not be predicted from the preoperative factors considered, spur formation at the concave side of the curve may be a candidate factor. The results of this study indicate that spinal fixation to halt deformity progression is not always necessary if the patient's pathological condition derives mainly from canal stenosis.

Surgical strategy in adult lumbar scoliosis: the utility of categorization into 2 groups based on primary symptom, each with 2-year minimum follow-up

STUDY DESIGN

This is a cohort investigation of 2 categories of patients with adult lumbar scoliosis.

OBJECTIVE

To demonstrate the different surgical strategies between 2 categories of patients with adult lumbar scoliosis based on their symptoms and radiological findings.

SUMMARY OF BACKGROUND DATA

It has been hypothesized that patients with adult lumbar scoliosis should be categorized, when possible, into 2 distinct groups on the basis of clinical symptoms and that this categorization can best guide surgical treatment strategy.

METHODS

Between January 2002 and December 2004, 43 patients with adult lumbar scoliosis underwent surgical treatment. Each patient was categorized into 1 of 2 distinct groups before surgery. Group 1 patients had primary symptoms related to stenosis, and the surgical strategy was posterior local decompression with or without instrumented fusion at the treated levels. Group 2 patients had primary symptoms related to symptomatic or progressive deformity, and the surgical strategy was instrumented fusion, to include at least the end vertebrae, by posterior or by combined anterior/posterior approach, with or without selective decompression. Preoperative and postoperative radiographical evaluation was performed. Preoperative and postoperative clinical outcomes utilized were the Modified Prolo Scale and the Patient Satisfaction Index (PSI).

RESULTS

The average age at the time of treatment was 61 years. The mean follow-up time after surgery was 35 months (range, 24-65 months). A radiographical grade I fusion (definitely fused) was achieved in 65% of cases. Failure of fusion was seen in 9.1% for group 1 and 9.5% for group 2. In group 1, the average Modified Prolo Scale was 9.5 before surgery and 15.9 at follow-up and total satisfaction rate (PSI) was 82%. In group 2, the average Modified Prolo Scale was 10.9 before surgery and 17.0 at follow-up and total satisfaction rate (PSI) was 86%.

CONCLUSION

Categorization of patients into 2 groups, 1 with primarily stenosis symptoms and 1 with primarily deformity symptoms, may be effective for surgical decision making. These 2 categories of patients may be expected to enjoy similar clinical improvements after surgical treatment.

Short fusion versus long fusion for degenerative lumbar scoliosis

The extent of fusion for degenerative lumbar scoliosis has not yet been determined. The purpose of this study was to compare the results of short fusion versus long fusion for degenerative lumbar scoliosis. Fifty patients (mean age 65.5 +/- 5.1 years) undergoing decompression and fusion with pedicle screw instrumentation were evaluated. Short fusion was defined as fusion within the deformity, not exceeding the end vertebra. Long fusion was defined as fusion extended above the upper end vertebra. The lower end vertebra was included in the fusion in all the patients. The short fusion group included 28 patients and the long fusion group included 22 patients. Patients' age and number of medical co-morbidities were similar in both the groups. The number of levels fused was 3.1 +/- 0.9 segments in the short fusion group and 6.5 +/- 1.5 in the long fusion group. Before surgery, the average Cobb angle was 16.3 degrees (range 11-28 degrees ) in the short fusion group and 21.7 degrees (range 12-33 degrees ) in the long fusion group. The correction of the Cobb angle averaged 39% in the short fusion group and 72% in the long fusion group with a statistical difference (P = 0.001). Coronal imbalance improved significantly in the long fusion group more than in the short fusion group (P = 0.03). The correction of lateral listhesis was better in the long fusion group (P = 0.02). However, there was no difference in the correction of lumbar lordosis and sagittal imbalance between the two groups. Ten of the 50 patients had additional posterolateral lumbar interbody fusion at L4-5 or L5-S1. The interbody fusion had a positive influence in improving lumbar lordosis, but was ineffective at restoring sagittal imbalance. Early perioperative complications were likely to develop in the long fusion group. Late complications included adjacent segment disease, loosening of screws, and pseudarthrosis. Adjacent segment disease developed in ten patients in the short fusion group, and in five patients in the long fusion group. In the short fusion group, adjacent segment disease occurred proximally in all of the ten patients. Loosening of distal screws developed in three patients, and pseudarthrosis at L5-S1 in one patient in the long fusion group. Reoperation was performed in four patients in the long fusion group and three patients in the short fusion group. In conclusion, short fusion is sufficient for patients with small Cobb angle and good spinal balance. For patients with severe Cobb angle and rotatory subluxation, long fusion should be carried out to minimize adjacent segment disease. For patients who have severe sagittal imbalance, spinal osteotomy is an alternative technique to be considered. As long fusion is likely to increase early perioperative complications, great care should be taken for high-risk patients to avoid complications.

Degenerative lumbar scoliosis: evaluation and management

Degenerative lumbar scoliosis is a lateral deviation of the spine that typically develops after age 50 years. Clinical presentation varies, but the deformity frequently is associated with loss of lordosis, axial rotation, lateral listhesis, and spondylolisthesis. Although the etiology is unclear, degenerative scoliosis is associated with degenerative disk disease, facet incompetence, and hypertrophy of the ligamenta flava, typically leading to neurogenic claudication and back pain. Rarely, sagittal or coronal imbalance may develop. Indications for treatment include pain, progressive deformity, radiculopathy or myelopathy, and cosmetic deformity. Nonsurgical care focuses on patient education, exercise, and nonnarcotic medication. Surgical management should be considered carefully, balancing the benefits and risks for the patient.