Impact of body mass index on adjacent segment disease after lumbar fusion for degenerative spine disease

[The impact of spinopelvic parameters on the rate of adjacent segment instability after short-segment spinal fusion]

AIM

The objective of this study is to determine the impact of postoperative spinopelvic parameters on the development of adjacent segment instability after single-level lumbar fusion.

MATERIAL AND METHODS

A total of 116 patients with degenerative spine conditions after lumbar fusion were enrolled in this study and subdivided into two groups. Group I consisted of 24 patients with signs of adjacent segment instability; Group II included 92 patients without signs of instability. The minimal follow-up period was 24 months.

RESULTS

The mean postoperative lumbar lordotic (LL) angle in both groups was within the normal range (-60.9±12); no statistically significant intergroup differences were revealed (56.6±12.1 and 58.4±11.2 for Groups I and II, respectively; p=0.314). In Group I patients, the mean pelvic incidence (PI) angle differed significantly from the mean PI values in Group II patients (70.4±7.6 and 53.2±8.4, respectively; p=0.006) and from the normal PI values (51.9±10). Therefore, the mean difference between PI and LL (PI-LL) angles in the Group I patients was significantly higher than in Group II (16.2±5.4 and 4.8±8.6, respectively; p=0.004). Significant PI-LL mismatch (PI-LL ≥10°) was observed in 22 (91.7%) patients in Group I and in 11 (11.95%) patients in Group II. According to regression analysis data, the PI-LL mismatch was identified as a risk factor for adjacent segment instability; the odds ratio =4.2; 95% confidence interval 1.46-12.25; and p=0.007.

CONCLUSION

Patients with the high PI value and low LL value have a significantly higher risk of adjacent segment instability after short-segment spinal fusion.

Reoperation rates and risk factors for revision 4 years after dynamic stabilization of the lumbar spine

BACKGROUND CONTEXT

The concept of dynamic stabilization (DS) of the lumbar spine for treatment of degenerative instability has been introduced almost two decades ago. Dynamic stabilization follows the principle of controlling movement in the coronal plane by providing load transfer of the spinal segment without fusion and, at the same time, reducing side effects such as adjacent segment disease (ASD). So far, only little is known about revision rates after DS due to ASD and screw loosening (SL).

PURPOSE

The present study aimed to evaluate the longitudinal revision rates following dynamic pedicle screw stabilization in the lumbar spine and to determine specific risk factors predictive for ASD, SL, and overall reoperation in a large cohort with considerable follow-up.

DESIGN

We carried out a post hoc analysis of a prospectively collected database in a level I spine center.

PATIENTS EXAMPLE

The patient sample comprised 283 (151 female/132 male) consecutive patients suffering from painful degenerative lumbar segmental instability with or without spinal stenosis who underwent DS of the lumbar spine (Ulrich Cosmic, Ulrich Medical, Ulm, Germany) between January 2008 and December 2011.

OUTCOME MEASURES

Longitudinal reoperation rate and risk factors predictive for revision surgery were evaluated.

METHODS

We analyzed the longitudinal reoperation rate due to ASD and SL and overall reoperation. Risk factors such as age, gender, body mass index, lumbar lordosis (LL), number of segments, and number of previous surgeries were taken into account. Regular and mixed model logistic regressions were performed to determine risk factors for revision surgery on a patient and on a screw level.

RESULTS

The mean age was 65.7±10.2 years (range 31-88). One hundred thirty-two patients were stabilized in 1 segment, 134 in 2 segments, 15 in 3 segments, and 2 patients in 4 segments. Reoperation rate for ASD and SL after 1 year was 7.4 %, after 2 years was 15.0%, and after a mean follow-up of 51.4±15 months was 22.6%. Reasons for revision were SL in 19 cases (6.6%), ASD in 39 cases (13.7%), SL and ASD in 6 cases, hematoma in 2 cases (0.7%), cerebrospinal fluid fistulae in 3 cases (1.1%), infection in 6 cases (2.1%), and implant failure in 1 case (0.4%). The patients' age, the number of stabilized segments, and the number of previous surgeries and postoperative LL had a significant influence on the probability for revision surgery.

CONCLUSIONS

Reoperation rates after DS of the lumbar spine are comparable with rigid fixations. The younger the patient and the more segments are involved, the lower the LL and the more previous surgeries were found, the higher was the risk of revision. Risk of revision was almost twice as high in men compared with women. We therefore conclude that for clear clinical indication and careful evaluation of preoperative imaging data, DS using the Cosmic system seems to be a possible option. The presented data will help to further tailor indication and patient selection.

Incidence and risk factors for multiple medical complications in adult degenerative scoliosis long-level fusion

Adult degenerative scoliosis (ADS) surgery is known for its high incidence of complications. The propose of this study was to determine current complication rates and the predictors of medical complications in surgical ASD patients. A retrospective study of 153 ADS patients who underwent long level spinal fusion with 2-year follow-up between 2012 and 2017. The patient- and surgical-related risk factors for each individual medical complication were identified by using univariate testing. All patients were divided into groups with and without medical complication, infection, neurological complications, and cardiopulmonary complications, respectively. Potential risk factors were identified using univariate testing. Multivariate Logistic regression was used to evaluate independent predictors of medical complications. The total medical complication incidence was 26.1%. Patient-related independent risk factors for the development of medical complications included diabetes, smoking; for infection were diabetes and smoking; for neurological complications were BMI and diabetes; for cardiopulmonary complications were hypertension, smoking and cardiac comorbidity. Surgical-related independent risk factors for the development of medical complications were fusion level, operative time, osteotomy, blood transfusion and LOS; for infection were fusion level, blood transfusion, and LOS; for neurological complication were fusion level, osteotomy and blood transfusion; for cardiopulmonary complication were fusion level. Diabetes and smoking were the most common patient-related independent risk factors increase the development of each individual medical complication. On the other hand, fusion levels and blood transfusion were the most common surgical-related independent risk factors increase the development of each individual medical complication. Prevention of these risk factors can reduce the incidence of complications in Chinese patients with ADS surgery.

Risk factors for medical complications after long-level internal fixation in the treatment of adult degenerative scoliosis

PURPOSE

This study evaluates baseline patient characteristics and surgical parameters for risk factors of medical complications in ASD patients received posterior long level internal fixation.

METHODS

Analysis of consecutive patients who underwent posterior long-level instruction fixation for adult degenerative scoliosis (ADS) with a minimum of two year follow-up was performed. Pre-operative risk factors, intraoperative variables, peri-operative radiographic parameters, and surgical-related risk factors were collected to analyze the effect of risk factors on medical complications. Patients were separated into groups with and without medical complication. Then, complication group was further classified as major or minor medical complications. Potential risk factors were identified by univariate testing. Multivariate logistic regression was used to evaluate independent predictors of medical complications.

RESULTS

One hundred and thirty-one ADS patients who underwent posterior long segment pedicle screws fixation were included. Total medical complication incidence was 25.2%, which included infection (12.2%), neurological (11.5%), cardiopulmonary (7.6%), gastrointestinal (6.1%), and renal (1.5%) complications. Overall, 7.6% of patients developed major medical complications, and 17.6% of patients developed minor medical complications. The radiographic parameters of pre-operative and last follow-up had no significant difference between the groups of medical complications and the major or minor medical complications subgroups. However, the incidence of cerebrospinal fluid leak (CFL) in patients who without medical complications was much lower than that with medical complications (18.4 vs. 42.4%, P = 0.005). Independent risk factors for development of medical complications included smoking (OR = 6.45, P = 0.012), heart disease (OR = 10.07, P = 0.012), fusion level (OR = 2.12, P = 0.001), and length of hospital stay (LOS) (OR = 2.11, P = 0.000). Independent risk factors for development of major medical complications were diabetes (OR 6.81, P = 0.047) and heart disease (OR = 5.99, P = 0.049). Except for the last follow-up, Oswestry Disability Index and visual analog scale of the patient experienced medical complications trend higher score; the clinical outcomes have no significant difference between the medical and major complications groups.

CONCLUSION

Heart disease comorbidity is an independent risk factor for both medical and major medical complications. Smoking, fusion level, and LOS are independent risk factors for medical complication. Diabetes is the independent risk factors for major medical complications.

Cortical bone trajectory screws fixation in lumbar adjacent segment disease: A technique note with case series

Lumbar adjacent segment disease after lumbar fusion surgery often requires surgical intervention. However, subsequent surgical treatment often needs to expose and remove all of the previous instruments. This additional surgery leads to significant post-operative pain, muscular fibrosis, poor wound healing and infection, etc. From October 2015 to March 2016, we collected six cases underwent cortical bone trajectory screws fixation with minimal invasive inter-body cage fusion for lumbar adjacent segment disease. Patients in the study all had improvement after surgery without recurrence or instruments failure during follow-up. The technique negates removal of pre-existing instruments and when combined with minimal invasive fusion surgery, the wound length, blood loss and soft tissue damage could be reduced compared with traditional surgery. We introduce the surgical procedures in detail and wish this technique could be an option for spine surgeons who encounter a similar situation.

Adjacent Segment Disease in the Cervical and Lumbar Spine

Adjacent segment disease (ASD) is disappointing long-term outcome for both the patient and clinician. In contrast to adjacent segment degeneration, which is a common radiographic finding, ASD is less common. The incidence of ASD in both the cervical and lumbar spine is between 2% and 4% per year, and ASD is a significant contributor to reoperation rates after spinal arthrodesis. The etiology of ASD is multifactorial, stemming from existing spondylosis at adjacent levels, predisposed risk to degenerative changes, and altered biomechanical forces near a previous fusion site. Numerous studies have sought to identify both patient and surgical risk factors for ASD, but a consistent, sole predictor has yet to be found. Spinal arthroplasty techniques seek to preserve physiological biomechanics, thereby minimizing the risk of ASD, and long-term clinical outcome studies will help quantify its efficacy. Treatment strategies for ASD are initially nonoperative, provided a progressive neurological deficit is not present. The spine surgeon is afforded many surgical strategies once operative treatment is elected. The goal of this manuscript is to consider the etiologies of ASD, review its manifestations, and offer an approach to treatment.

Associations between Obesity and Spinal Diseases: A Medical Expenditure Panel Study Analysis

Background: The link between body weight status and spinal diseases has been suggested by a number of cross-sectional and cohort studies with a limited range of patient populations. No population-representative samples have been used to examine the link between obesity and spinal diseases. The present study is based on a nationally representative sample drawn from the Medical Expenditure Panel Survey. Methods: Using the cross-sectional sample of the 2014 Medical Expenditure Panel Study, we built four weighted logistic regression analyses of the associations between body weight status and the following four spinal diseases: low back pain, spondylosis, other cervical disorders and intervertebral disc disorder (IDD). Each respondent's body weight status was used as the key independent variable with three categories: normal/underweight, overweight, and obese. We controlled for marital status, gender, age, smoking status, household income, health insurance coverage, educational attainment and the use of health services for other major categories of diseases. Results: A total sample of 23,048 respondents was used in our analysis. Overweight and obese respondents, as compared to normal/underweight respondents, were more likely to develop lower back problems (Overweight: logged odds = 0.218, p < 0.01; Obese: logged odds = 0.395, p < 0.001) and IDD (Overweight: logged odds = 0.441, p < 0.05; Obese: logged odds = 0.528, p < 0.001). The associations between bodyweight status and spondylitis were statistically insignificant (Overweight: logged odds = 0.281, p = 0.442; Obese: logged odds = 0.680, p = 0.104). The associations between body weight status and other cervical disorders (Overweight: logged odds = -0.116, p = 0.304; Obese: logged odds = -0.160, p = 0.865) were statistically insignificant. Conclusions: As the first study using a national sample to study bodyweight and spinal diseases, our paper supports the hypothesis that obesity adds to the burden of low back pain and IDD. Longitudinal and interventional studies are needed to understand the specific mechanisms behind these positive associations.

Incidence and risk factors of adjacent segment disease following posterior decompression and instrumented fusion for degenerative lumbar disorders

The purpose of this study was to explore incidence and risk factors of adjacent segment disease (ASD) following posterior decompression and instrumented fusion for degenerative lumbar disorders, and hope to provide references in decision making and surgical planning for both spinal surgeon and surgically treated patients.By retrieving the medical records from January 2011 to December 2013 in our hospital, 237 patients were retrospectively reviewed. According to the occurrence of ASD at follow up, patients were divided into 2 groups: ASD and N-ASD group. To investigate risk values for the occurrence of ASD, 3 categorized factors were analyzed statistically: Patient characteristics: age, sex, body mass index (BMI), bone mineral density (BMD), duration. Surgical variables: surgical strategy, number of fusion level, surgery segment, surgery time, blood loss, intraoperative superior facet joint violation. Radiographic parameters: preoperative lumbar lordosis, preoperative angular motion at adjacent segment, preoperative adjacent segment disc degeneration, preoperative paraspinal muscle degeneration.Postoperative ASD was developed in 15 of 237 patients (6.3%) at final follow up. There was no statistically significant difference between the 2 groups in patient characteristics of age, sex composition, BMD, duration, while the BMI was higher in ASD group than that in N-ASD group. There was no difference in surgical variables of surgical strategy, number of fusion level, surgery segment, surgery time, blood loss, while intraoperative superior facet joint violation was more common in ASD group than that in N-ASD group. There was no difference in radiographic parameters of preoperative lumbar lordosis, preoperative paraspinal muscle degeneration, while preoperative adjacent segment disc degeneration were more severe in ASD group than that in N-ASD group. The Logistic regression analysis revealed that, BMI >25 kg/m, preoperative disc degeneration, and superior facet joint violation were independently associated with ASD.In conclusion, higher BMI, preoperative disc degeneration at adjacent segment and intraoperative superior facet joint violation are risk factors for ASD. Patients who are overweight or obesity and with preoperative disc degeneration at adjacent segment should be fully informed the risk of ASD. For surgeons, it is essential to prevent superior facet joint violation in pedicle screw insertion procedure.

Comparison of pedicle screw–based dynamic stabilization and fusion surgery in the treatment of radiographic adjacent-segment degeneration: a retrospective analysis of single L5–S1 degenerative spondylosis covering 4 years

OBJECTIVE

Pedicle screw–based dynamic spinal stabilization systems (PDSs) were devised to decrease, theoretically, the risk of long-term complications such as adjacent-segment degeneration (ASD) after lumbar fusion surgery. However, to date, there have been few studies that fully proved that a PDS can reduce the risk of ASD. The purpose of this study was to examine whether a PDS can influence the incidence of ASD and to discuss the surgical coping strategy for L5–S1 segmental spondylosis with preexisting L4–5 degeneration with no related symptoms or signs.

METHODS

This study retrospectively compared 62 cases of L5–S1 segmental spondylosis in patients who underwent posterior lumbar interbody fusion (n = 31) or K-Rod dynamic stabilization (n = 31) with a minimum of 4 years' follow-up. The authors measured the intervertebral heights and spinopelvic parameters on standing lateral radiographs and evaluated preexisting ASD on preoperative MR images using the modified Pfirrmann grading system. Radiographic ASD was evaluated according to the results of radiography during follow-up.

RESULTS

All 62 patients achieved remission of their neurological symptoms without surgical complications. The Kaplan-Meier curve and Cox proportional-hazards model showed no statistically significant differences between the 2 surgical groups in the incidence of radiographic ASD (p > 0.05). In contrast, the incidence of radiographic ASD was 8.75 times (95% CI 1.955–39.140; p = 0.005) higher in the patients with a preoperative modified Pfirrmann grade higher than 3 than it was in patients with a modified Pfirrmann grade of 3 or lower. In addition, no statistical significance was found for other risk factors such as age, sex, and spinopelvic parameters.

CONCLUSIONS

Pedicle screw–based dynamic spinal stabilization systems were not found to be superior to posterior lumbar interbody fusion in preventing radiographic ASD (L4–5) during the midterm follow-up. Preexisting ASD with a modified Pfirrmann grade higher than 3 was a risk factor for radiographic ASD. In the treatment of degenerative diseases of the lumbosacral spine, the authors found that both of these methods are feasible. Also, the authors believe that no extra treatment, other than observation, is needed for preexisting degeneration in L4–5 without any clinical symptoms or signs.

Locomotive syndrome is associated with body composition and cardiometabolic disorders in elderly Japanese women

Background

A concept referred to as locomotive syndrome (LS) was proposed by the Japanese Orthopaedic Association in order to help identify middle-aged and older adults who may be at high risk of requiring healthcare services because of problems associated with locomotion. Cardiometabolic disorders, including obesity, hypertension, diabetes, and dyslipidemia, have a high prevalence worldwide. The purpose of this study was to determine the associations between LS and both body composition and cardiometabolic disorders.

Methods

The study participants were 165 healthy adult Japanese women volunteers living in rural areas. LS was defined as a score ≥16 on the 25-question Geriatric Locomotive Function Scale (GLFS-25). Height, body weight, body fat percentage, body mass index (BMI), and bone status were measured. Bone status was evaluated by quantitative ultrasound (i.e., the speed of sound [SOS] of the calcaneus) and was expressed as the percent of Young Adult Mean of the SOS (%YAM). Comorbid conditions of hypertension, hyperlipidemia, and diabetes were assessed using self-report questionnaires.

Results

Twenty-nine participants (17.6 %) were classed as having LS. The LS group was older, shorter, and had a higher body fat percentage, a higher BMI, and lower bone status than the non-LS group. Multiple logistic regression analysis showed that participants with a BMI ≥23.5 kg/m² had a significantly higher risk for LS than those with a BMI <23.5 kg/m² (odds ratio [OR] = 3.78, p < 0.01). Furthermore, GLFS-25 scores were higher in participants with than those without hypertension, diabetes, or obesity, and significantly increased with the number of present disorders.

Conclusions

These findings suggest that BMI may be a useful screening tool for LS. Furthermore, because hypertension and diabetes were associated with LS, the prevention of these disorders accompanied by weight management may help protect against LS.

Electronic supplementary material

The online version of this article (doi:10.1186/s12877-016-0339-6) contains supplementary material, which is available to authorized users.

Incidence and risk factors for the progression of proximal junctional kyphosis in degenerative lumbar scoliosis following long instrumented posterior spinal fusion

The aim of this study was to identify the prevalence of proximal junctional kyphosis (PJK) in degenerative lumbar scoliosis (DLS) following long instrumented posterior spinal fusion, and to search for predictable risk factors for the progression of junctional kyphosis.In total 98 DLS patients with a minimum 2-year follow-up were reviewed prospectively. According to the occurrence of PJK at the last follow-up, patients were divided into 2 groups: PJK group and non-PJK group. To investigate risk values for the progression of PJK, 3 categorized factors were analyzed statistically: patient characteristics-preoperative data of age, sex, body mass index (BMI), bone mineral density (BMD) were investigated; surgical variables-the most proximal and distal levels of the instrumentation, the number of instrumented levels; pre- and postoperative radiographic parameters include the scoliotic angle, sagittal vertical axis, thoracic kyphosis, thoracolumbar junctional angle, lumbar lordosis, pelvic incidence, pelvic tilt, and sacral slope.PJK was developed in 17 of 98 patients (17.3%) until to the final follow-up and were enrolled as the PJK group, and 81 patients without PJK at final follow-up were enrolled as the non-PJK group. There was no statistically significant difference between the 2 groups in age at operation (P = 0.900). The patient's sex was excluded in statistical analysis because of the predominance of female patients. There were statistically significant difference between the 2 groups in BMI ([25.5 ± 1.7] kg/m in the PJK group and [23.6 ± 1.9] kg/m in the non-PJK group, P < 0.001) and BMD ([-1.4 ± 0.8] g/cm in the PJK group and [-0.7 ± 0.3] g/cm in the non-PJK group, P < 0.001). No specific surgery-related variables were found to be associated with an increased risk of developing PJK, except when the most proximal instrumented vertebrae stopped at thoracolumbar junction (T11-L1). The upper instrumentation vertebrae (UIV) at thoracolumbar junction was more common in the PJK group than that in the non-PJK group (P = 0.007). No preoperative and early postoperative variable did reveal a statistically significant difference between the 2 groups. When included in a multivariate logistic regression model, BMI>25 kg/m, osteoporosis, and UIV at thoracolumbar junction were independently associated with PJK.In conclusion, osteoporosis, obesity, and UIV at thoracolumbar junction are risk factors for the development and progression of PJK in DLS patients following long instrumented posterior spinal fusion. Antiosteoporosis treatment extends the fusion level above the thoracolumbar region and controlling body weight before and after surgery could provide opportunities to reduce the rate of PJK and to improve therapeutic outcomes.

The impact of body habitus on outcomes after aneurysmal subarachnoid hemorrhage: a Nationwide Inpatient Sample analysis

OBJECTIVE Although the prevalence of obesity is increasing rapidly both nationally and internationally, few studies have analyzed outcomes among obese patients undergoing cranial neurosurgery. The goal of this study, which used a nationwide data set, was to evaluate the association of both obesity and morbid obesity with treatment outcomes among patients with aneurysmal subarachnoid hemorrhage (SAH); in addition, the authors sought to analyze how postoperative complications for obese patients with SAH differ by the treatment modality used for aneurysm repair. METHODS Clinical data for adult patients with SAH who underwent microsurgical or endovascular aneurysm repair were extracted from the Nationwide Inpatient Sample (NIS). The body habitus of patients was classified as nonobese (body mass index [BMI] < 30 kg/m²), obese (BMI ≥ 30 kg/m² and ≤ 40 kg/m²), or morbidly obese (BMI > 40 kg/m²). Multivariable logistic regression analyzed the association of body habitus with in-hospital mortality rate, complications, discharge disposition, and poor outcome as defined by the composite NIS-SAH outcome measure. Covariates included patient demographics, comorbidities (including hypertension and diabetes), health insurance status, the NIS-SAH severity scale, treatment modality used for aneurysm repair, and hospital characteristics. RESULTS In total, data from 18,281 patients were included in this study; the prevalence of morbid obesity increased from 0.8% in 2002 to 3.5% in 2011. Obese and morbidly obese patients were significantly younger and had a greater number of comorbidities than nonobese patients (p < 0.001). Mortality rates for obese (11.5%) and morbidly obese patients (10.5%) did not significantly differ from those for nonobese patients (13.5%); likewise, no differences in neurological complications or poor outcome were observed among these 3 groups. Morbid obesity was associated with significantly increased odds of several medical complications, including venous thromboembolic (OR 1.52, 95% CI 1.01-2.30, p = 0.046) and renal (OR 1.64, 95% CI: 1.11-2.43, p = 0.01) complications and infections (OR 1.34, 95% CI 1.08-1.67, p = 0.009, attributable to greater odds of urinary tract and surgical site infections). Moreover, morbidly obese patients had higher odds of a nonroutine hospital discharge (OR 1.33, 95% CI 1.03-1.71, p = 0.03). Patients with milder obesity had decreased odds of some medical complications, including cardiac, pulmonary, and infectious complications, primarily among patients who had undergone coil embolization. CONCLUSIONS In this study involving a nationwide administrative database, milder obesity was not significantly associated with increased mortality rates, neurological complications, or poor outcomes after SAH. Morbid obesity, however, was associated with increased odds of venous thromboembolic, renal, and infectious complications, as well as of a nonroutine hospital discharge. Notably, milder obesity was associated with decreased odds of some medical complications, primarily in patients treated with coiling.

Paraspinal muscle, facet joint, and disc problems: risk factors for adjacent segment degeneration after lumbar fusion

BACKGROUND CONTEXT

Adjacent segment degeneration (ASD) is one of the major complications after lumbar fusion. Several studies have evaluated the risk factors of ASD. Although the paraspinal muscles play an important role in spine stability, no study has assessed the relationship between paraspinal muscle atrophy and the incidence of ASD after lumbar fusion.

PURPOSE

In the present study, we aimed to verify the known risk factors of ASD, such as body mass index (BMI), preoperative adjacent facet joint degeneration, and disc degeneration, and to assess the relationship between paraspinal muscle atrophy and ASD.

STUDY DESIGN

This is a retrospective 1:1 pair analysis matched by age, sex, fusion level, and follow-up period.

PATIENT SAMPLE

To calculate the appropriate sample size for the study, we performed a pre-study analysis of the paraspinal muscle cross-sectional area (CSA), and estimated that at least 35 cases would be needed for each group. Among the 510 patients who underwent posterior lumbar fusion for degenerative lumbar disease between January 2009 and October 2009, a total of 50 patients with ASD after surgery were selected. Another group of 50 matched patients with degenerative lumbar disease without ASD after spinal fusion were selected as the control group. Each patient in the ASD group was matched with a control patient according to age, sex, fusion level, and follow-up period.

OUTCOME MEASURES

Radiographic measurements and demographic data were reviewed.

METHODS

The risk factors considered were higher BMI, preoperative adjacent segment disc and facet degeneration, and preoperative paraspinal muscle atrophy and fatty degeneration. The radiographic data were compared between the ASD and control groups to determine the predictive factors of ASD after posterior lumbar fusion by using logistic regression analysis. The study was not externally funded. The authors have no conflict of interest to declare.

RESULTS

Multivariate logistic regression analysis indicated that higher BMI (odds ratio [OR]: 1.353, p=.008), preoperative facet degeneration on computed tomography examination (OR: 3.075, p=.011), disc degeneration on magnetic resonance imaging (MRI) (OR: 2.783, p=.003), fatty degeneration (OR: 1.080, p=.044), and a smaller relative CSA of the paraspinal muscle preoperatively (OR: 0.083, p=.003) were significant factors for predicting the development of ASD.

CONCLUSIONS

The occurrence of radiological ASD is most likely multifactorial, and is associated with a higher BMI, preexisting facet and disc degeneration on preoperative examination, and a smaller preoperative relative CSA of the paraspinal muscle on MRI.

The Impact of Obesity on the Outcome of Decompression Surgery in Degenerative Lumbar Spinal Canal Stenosis: Analysis of the Lumbar Spinal Outcome Study (LSOS): A Swiss Prospective Multicenter Cohort Study

STUDY DESIGN

Prospective, multicenter cohort study including 8 medical centers of the Cantons Zurich, Lucerne, and Thurgau, Switzerland.

OBJECTIVE

The aim of the study was to assess whether obese patients benefit after decompression surgery for degenerative lumbar spinal stenosis (DLSS).

SUMMARY AND BACKGROUND DATA

Lumbar decompression surgery has been shown to improve quality of life in patients with DLSS. In the existing literature, the efficacy of lumbar decompression in the obese population remains controversial.

METHODS

Baseline patient characteristics and outcomes were analyzed at 6 and 12 months follow-up with the Spinal Stenosis Measure (SSM), the Numeric Rating Scale (NRS), Feeling Thermometer (FT), the EQ-5D-EL, and the Roland and Morris Disability Questionnaire (RMDQ). Body mass index (BMI) was classified into 3 categories according to the WHO. Minimal clinically important differences (MCIDs) in SSM for different BMI categories were considered as main outcome.

RESULTS

Of the 656 patients in the Lumbar Spinal Outcome Study database as of end of October 2014, 166 patients met the inclusion criteria. Fifty (30.1%) had a BMI less than 25 (underweight and normal weight group), 72 (43.4%) had a BMI between 25 and less than 30 (preobesity group), and 44 (26.5%) patients had a BMI at least 30 (obese group). We found for the main outcome that in obese patients 36% reached MCID at 6 months, and 48% at 12 months. The estimated odds ratios for MCID in the obese group were 0.78 (0.34-1.82) at 6 months and 0.99 (0.44-2.23) at 12 months in a logistic regression model adjusting for levels of laminectomy. In the additional outcomes, SSM, NRS, FT, and RMDQ showed statistically significant mean improvements in the 6 and 12 months follow-up.

CONCLUSION

Obese patients can expect clinical improvement after lumbar decompression for DLSS, but the percentage of patients with a meaningful improvement is lower than in the group of patients with underweight, normal weight, and preobese weight at 6 and 12 months.

Adjacent level disease following lumbar spine surgery: A review

Background:

Instrumented lumbar spine surgery is associated with an increased risk of adjacent segment disease (ASD). Multiple studies have explored the various risk factors contributing to ASD that include; fusion length (especially, three or more levels), sagittal malalignment, facet injury, advanced age, and prior cephalad degenerative disease.

Methods:

In this selective review of ASD, following predominantly instrumented fusions for lumbar degenerative disease, patients typically underwent open versus minimally invasive surgery (MIS), transforaminal lumbar interbody fusions (TLIFs), posterior lumbar interbody fusions (PLIFs), or rarely posterolateral lumbar instrumented or noninstrumented fusions (posterolateral lumbar fusion).

Results:

The incidence of ASD, following open or MI lumbar instrumented fusions, ranged up to 30%; notably, the addition of instrumentation in different series did not correlate with improved outcomes. Alternatively, in one series, at 164 postoperative months, noninstrumented lumbar fusions reduced the incidence of ASD to 5.6% versus 18.5% for ASD performed with instrumentation. Of interest, dynamic instrumented/stabilization techniques did not protect patients from ASD. Furthermore, in a series of 513 MIS TLIF, there was a 15.6% incidence of perioperative complications that included; a 5.1% frequency of durotomy and a 2.3% instrumentation failure rate.

Conclusions:

The incidence of postoperative ASD (up to 30%) is greater following either open or MIS instrumented lumbar fusions (e.g., TLIF/PLIF), while decompressions with noninstrumented fusions led to a much smaller 5.6% risk of ASD. Other findings included: MIS instrumented fusions contributed to higher perioperative complication rates, and dynamic stabilization did not protect against ASD.