Glial fibrillary acidic protein is a robust biomarker in cerebrospinal fluid and peripheral blood after traumatic spinal cord injury: a prospective pilot study.

PURPOSE: Biochemical biomarkers to determine the injury severity and the potential for functional recovery of traumatic spinal cord injury (TSCI) are highly warranted; however, it remains to be clarified whether cerebrospinal fluid (CSF) or peripheral blood (PB) is the ideal sample media. This study aims to measure and compare biomarker concentrations in CSF and PB and to explore associations between biomarker concentrations and injury severity, i.e., American Spinal Injury Association (ASIA) Impairment Scale (AIS) grade, and biomarker concentrations and clinical outcome, i.e., AIS grade improvement and Spinal Cord Independent Measure version III (SCIM-III) score. METHODS: From 2018 to 2020, we conducted a single-center prospective pilot study of TSCI patients (n=15) and healthy controls (n=15). Sample collection and clinical outcome assessment were performed at median 13 h [IQR: 19], 9 days [IQR: 2], and 148 days [IQR: 49] after TSCI. Concentrations of neuron-specific enolase (NSE); glial fibrillary acid protein (GFAP); neurofilament light chain (NfL); interferon-γ (IFN-γ); interleukin (IL)-1ß, IL-2, IL-4, IL-6, IL-8, IL-10, IL-12p70, and IL-13; and tumor necrosis factor α (TNF-α) were measured and associated to clinical outcomes. RESULTS: The biomarker concentrations were higher in CSF than PB. CSF concentrations of GFAP, NSE, IFN-y, TNF-a, IL-2, IL-12p70, IL-4, IL-10, and IL-13 and PB concentrations of GFAP and IFN-y were significantly associated with AIS grade, but not with AIS grade improvement or SCIM-III score. CONCLUSIONS: Our results support GFAP as a potential diagnostic biomarker that may be measured in CSF as well as PB.

Evaluation of cefuroxime concentration in the intrathecal and extrathecal compartments of the lumbar spine-an experimental study in pigs.

BACKGROUND AND PURPOSE: Optimal antibiotic prophylaxis is crucial to prevent postoperative infection in spinal surgery. Sufficient time above the minimal inhibitory concentration (fT > MIC) for relevant bacteria in target tissues is required for cefuroxime. We assessed cefuroxime concentrations and fT > MIC of 4 µg·ml-1 for Staphylococcus aureus in the intrathecal (spinal cord and cerebrospinal fluid, CSF) and extrathecal (epidural space) compartments of the lumbar spine. EXPERIMENTAL APPROACH: Eight female pigs were anaesthetized and laminectomized at L3-L4. Microdialysis catheters were placed for sampling in the spinal cord, CSF, and epidural space. A single dose of 1500 mg cefuroxime was administered intravenously over 10 min. Microdialysates and plasma were obtained continuously during 8 h. Cefuroxime concentrations were determined by ultra-high-performance liquid chromatography. KEY RESULTS: Mean fT > MIC (4 µg·ml-1 ) was 58 min in the spinal cord, 0 min in the CSF, 115 min in the epidural space, and 123 min in plasma. Tissue penetration was 32% in the spinal cord, 7% in the CSF, and 63% in the epidural space. CONCLUSION AND IMPLICATIONS: fT > MIC (4 µg·ml-1 ) and tissue penetration for cefuroxime were lower in the intrathecal compartments (spinal cord and CSF) than in the extrathecal compartment (epidural space) and plasma, suggesting a significant effect of the blood-brain barrier. In terms of fT > MIC, a single dose of 1500 mg cefuroxime seems inadequate to prevent intrathecal infections related to spinal surgery for bacteria presenting with a MIC target of 4 µg· ml-1 or above.

Subtherapeutic levels of cefuroxime inside a cannulated pedicle screw used in spine surgery: results from a porcine microdialysis study.

BACKGROUND AND PURPOSE: Minimally invasive spine surgery has continuously evolved for specific surgical procedures and patient populations to lower morbidity and the risk of postoperative bacterial infection. Perioperative antibiotic prophylaxis is an important preventive measure and local tissue concentrations can be quantified with microdialysis. Insertion of spinal implants induces tissue trauma and inflammation, which may affect antibiotic proximate implant concentrations. We compared perioperative cefuroxime concentrations inside a cannulated pedicle screw used in minimally invasive spine surgery with the opposite non-instrumented vertebral pedicle. MATERIALS AND METHODS: Microdialysis catheters were placed inside a cannulated pedicle screw and in the opposite non-instrumented vertebral pedicle of the same vertebra (L1) in 8 female pigs through a posterior lumbar surgical approach. Following a single-dose intravenous cefuroxime administration (1.5 g), dialysates and plasma were dynamically sampled over 8 hours. The primary endpoint was time above the cefuroxime clinical breakpoint minimal inhibitory concentration for Staphylococcus aureus of 4 µg/mL (T>MIC4). RESULTS: Median T>MIC4 was 0 h (range 0-0) inside the cannulated pedicle screw, 1.6 h (range 1.1-2.4) in non-instrumented vertebral pedicle, and 1.9 h (range 1.9-2.9) in plasma. CONCLUSION: A single-dose intravenous cefuroxime administration provided low and subtherapeutic concentrations for prevention of infection inside a cannulated pedicle screw in the lumbar spine. Therapeutic concentrations were achieved in the opposite non-instrumented vertebral pedicle up to 1.5-2 h. Therefore, additional prophylactic strategies may be considered in cannulated instrumented spine surgery, especially in high-risk patients. Alternative dosing regimens seem relevant in lumbar spine surgery lasting longer than 1.5 h.

The inflammatory response and blood-spinal cord barrier integrity in traumatic spinal cord injury: a prospective pilot study.

PURPOSE: Triggering of inflammatory responses and disruption of blood-spinal cord barrier (BSCB) integrity are considered pivotal events in the pathophysiology of traumatic spinal cord injury (TSCI). Yet, these events are poorly understood and described in humans. This study aims to describe inflammatory responses and BSCB integrity in human TSCI. METHODS: Fifteen TSCI patients and fifteen non-TSCI patients were prospectively recruited from Aarhus University Hospital, Denmark. Peripheral blood (PB) and cerebrospinal fluid (CSF) were collected at median day 0 [IQR: 1], median day 9 [IQR: 2], and median day 148 [IQR: 49] after injury. PB and CSF were analyzed for immune cells by flow cytometry, cytokines by multiplex immunoassay, and BSCB integrity by IgG Index. RESULTS: Eleven TSCI patients completed follow-up. Results showed alterations in innate and adaptive immune cell counts over time. TSCI patients had significantly increased cytokine concentrations in CSF at the first and second follow-up, while only concentrations of interleukin (IL)-4, IL-8, and tumor necrosis factor-α remained significantly increased at the third follow-up. In PB, TSCI patients had significantly increased IL-6, IL-8, and IL-10 concentrations and significantly decreased interferon-γ concentrations at the first follow-up. Results further showed increased IgG Index indicative of BSCB disruption in seven TSCI patients at the first follow-up, five TSCI patients at the second follow-up, and two patients at the third follow-up. CONCLUSIONS: Our results suggest that TSCI mainly triggers innate inflammatory responses that resolves over time, although with some degree of non-resolving inflammation, particularly in CSF. Our results cannot confirm BSCB disruption in all TSCI patients.

Cefuroxime concentrations in the anterior and posterior column of the lumbar spine - an experimental porcine study.

BACKGROUND CONTEXT: Surgical site infection following spine surgery is associated with increased morbidity and mortality. Perioperative antibiotic prophylaxis is a key factor in lowering the risk of acquiring an infection. Previous studies have assessed perioperative cefuroxime concentrations in the anterior column of the cervical spine with an anterior surgical approach. However, the majority of surgeries are performed in the posterior column and many surgeries involve the lumbar spine. PURPOSE: The objective of this study was to compare the perioperative tissue concentrations of cefuroxime in the anterior and posterior column during lumbar spine surgery with a posterior surgical approach. STUDY DESIGN: In vivo experimental pharmacokinetic study of cefuroxime concentrations in an acute preclinical porcine model. METHODS: The lumbar vertebral column was exposed from L1 to L5 in 8 female pigs. Microdialysis catheters were placed for sampling in the anterior column (vertebral body) and posterior column (posterior arch) within the same vertebra (L5). Cefuroxime (1.5 g) was administered intravenously. Microdialysates and plasma samples were continuously obtained over 8 hours. Cefuroxime concentrations were quantified by Ultra High Performance Liquid Chromatography Tandem Mass Spectrometry. The primary endpoint was the time above the cefuroxime clinical breakpoint minimal inhibitory concentration (T>MIC) for Staphylococcus aureus of 4 µg/mL. The secondary endpoint was tissue penetration (AUCtissue/AUCplasma). RESULTS: Mean T>MIC 4 µg/mL (95% confidence interval) was 123 min (105-141) in plasma, 97 min (79-115) in the anterior column and 93 min (75-111) in the posterior column. Tissue penetration (95% confidence interval) was incomplete for both the anterior column 0.48 (0.40-0.56) and posterior column 0.40 (0.33-0.48). CONCLUSIONS: T>MIC was comparable between the anterior and posterior column. Mean cefuroxime concentrations decreased below the clinical breakpoint minimal inhibitory concentration for S. aureus of 4 µg/mL after 123 minutes (plasma), 97 minutes (anterior column) and 93 minutes (posterior column). This is shorter than the duration of most lumbar spine surgeries, and therefore alternative dosing regimens should be considered in posterior open lumbar spine surgeries lasting more than 1.5 hours. CLINICAL SIGNIFICANCE: Open lumbar spine surgery often involves extensive soft tissue dissection, stripping and retraction of the paraspinal muscles which may impair the local blood flow exposing the lumbar vertebra to postoperative infections. A single intravenous administration of 1.5 g cefuroxime only provided sufficient prophylactic target tissue concentrations in the vertebra of the lumbar spine for up to 1.5 hours.

[Metastatic spinal cord compression syndrome].

Metastatic spinal cord compression can be due to the debut of cancer or terminally advanced disease, and symptoms are pain, limb weakness, hypoaesthesia and sphincter dysfunction. In patients with a cancer history, metastatic spinal cord compression must be suspected, which is why MRI is necessary. In case of neurological impairment, the patient must consult surgical and oncologic specialists at a university hospital, who can offer the best treatment, i.e. surgery in combination with radiotherapy or radiotherapy alone. Treatment gives higher one-year survival, preserved ambulatory function, increased life quality and less pain, as summarised in this review.

Length of stay, readmission, and mortality after primary surgery for pediatric spinal deformities: a 10-year nationwide cohort study.

BACKGROUND CONTEXT: Extended length of stay (extLOS) and unplanned readmissions after first time pediatric spinal deformity surgery are a considerable challenge to both the patient and the health-care system. To our knowledge, only a limited number of nationwide studies reporting short-term comorbidity with complete follow-up exist. PURPOSE: The purpose of this study was to identify the postoperative complications leading to extLOS, readmissions, and mortality within 90 days after surgery. Furthermore, to identify risk factors for readmission. DESIGN: Retrospective national cohort study. PATIENT SAMPLE: A nationwide registry study including all pediatric spinal deformity patients (≤21 years of age) undergoing primary surgery during 2006-2015 (n=1,310). OUTCOME MEASURES: Reasons for extLOS and 90-day readmissions as well as mortality risk. METHODS: Patients were identified by procedure and diagnosis codes in the Danish National Patient Registry (DNPR). Data on length of stay (LOS), readmissions, and mortality within 90 days were retrieved from the DNPR. Patients were categorized in six groups according to etiology. Reasons for extLOS and readmission were collected from medical records and discharge summaries. RESULTS: For the 1,310 patients, the median LOS was 8 days (interquartile range 7-9). Etiologies were idiopathic deformity (53%), neuromuscular deformity (23%), congenital/structural deformity (9%), spondylolisthesis (7%), Scheuermann kyphosis (5%), and syndromic deformity (3%). A total of 274 (21%) patients had extLOS and the most common reason was pain/mobilization issues but with considerable variation between etiologies; Scheuermann kyphosis (91%), idiopathic (59%), syndromic (44%), spondylolisthesis (38%), and congenital (30%). Pulmonary complications were the primary reason for extLOS in the neuromuscular group (22%). The 90-day readmission rate was 6%; 67% of readmissions were medical, mainly infections unrelated to the surgical site (23%); 33% of readmissions were surgical and 14% of patients required revision surgery. Neuromuscular deformity, spondylolisthesis, Scheuermann kyphosis, and LOS >9 days were independent risk factors for readmission; odds ratio (OR) 4.4 (95% confidence interval: 2.2-9.1, p<.01), OR 3.0 (1.1-8.0, p=.03), OR 4.9 (1.7-13.6, p<.01), and OR 1.8 (1.0-3.1, p=.04), respectively. The 90-day mortality risk was 0.4%. CONCLUSIONS: In this nationwide cohort, pain/mobilization issues are the most common reason for extLOS. The most common reason for readmission is infection unrelated to the surgical site. Readmission after pediatric spinal surgery is related to the etiology and increased focus on patients operated for neuromuscular deformity, spondylolisthesis and Scheuermann kyphosis is warranted.

Revision risk after pediatric spinal deformity surgery: a nationwide study with 2-year follow-up.

BACKGROUND CONTEXT: Revision risk after pediatric spine surgery is not well established and varies between deformity etiologies. PURPOSE: To report the 2-year revision risk following surgery for primary pediatric spinal deformity in a nationwide cohort and to evaluate potential risk factors and reasons for revision surgery. DESIGN: Retrospective nationwide cohort study. PATIENT SAMPLE: A national registry study of all pediatric spinal deformity patients undergoing surgery during 2006-2015 (n=1310). OUTCOME MEASURES: Two-year revision risk. METHODS: All patients ≤21 years of age undergoing spinal deformity surgery in Denmark during 2006-2015 were identified by procedure and diagnosis codes in the Danish National Patient Registry (DNPR). Data on revision surgery were retrieved from the DNPR. Patients were categorized in six groups according to etiology. Medical records were reviewed for reason for revision in all patients. Potential risk factors for revision were assessed with multiple logistic regression analyses and included age, etiology, sex, Charlson comorbidity index (CCI), and growth-preserving treatment. RESULTS: Patients were categorized according to etiology: idiopathic deformity (53%), neuromuscular deformity (23%), congenital/structural deformity (9%), spondylolisthesis (7%), Scheuermann's kyphosis (5%), and syndromic deformity (3%). Of 1,310 included patients, 9.2% underwent revision surgery within 2 years and 1.5% was revised more than once. Median time to revision was 203 (interquartile range 35-485) days. The multivariable logistic regression found significantly higher odds ratio (OR) for revision in patients with growth-preserving treatment (OR=5.1, 95% confidence interval [CI] 2.6-10.1), congenital deformity (OR=2.7, 95% CI 1.3-5.3), spondylolisthesis (OR=3.5, 95% CI 1.9-6.7), Scheuermann kyphosis (OR=3.9, 95% CI 1.9-8.3), and CCI score ≥3 (OR=2.5 95% CI 1.1-5.6). The most common reason for revision was implant failure (32.5%) followed by residual deformity and/or curve progression (15.8%). CONCLUSIONS: In this nationwide study, the 2-year revision risk after primary pediatric spinal deformity surgery is 9.2%. Risk factors for revision are etiology of congenital deformity, spondylolisthesis, Scheuermann kyphosis as well as patients with growth-preserving treatment and higher CCI. The most common reason for revision is implant failure.

New growth rod concept provides three dimensional correction, spinal growth, and preserved pulmonary function in early-onset scoliosis.

INTRODUCTION: This study aims to describe a novel minimal invasive early-onset scoliosis (EOS) growth rod concept, the Cody Bünger (CB) Concept, which combines concave interval distraction and contralateral-guided growth with apical control and to investigate the 3D deformity correction, the spinal growth, and the pulmonary development. METHOD: A series of 38 children with progressive EOS and growth potential, receiving a highly specialized surgical treatment, including primary and conversion cases. Mean age was 10.2 years (4.4-15.8) with a mean follow-up of 5.6 years, and they underwent 168/184 open/magnetic lengthening procedures. Outcomes were as follows: scoliosis, kyphosis, and lordosis angles; apical rotation; spinal length; apical translation; coronal and sagittal vertical alignment; complications; and pulmonary function in a subgroup. RESULTS: Scoliosis improved from mean 76° (46-129) to 35° (8-74) post-op and was 42° (13-83) at end of treatment. Apical rotation was reduced by 30% but was partially lost during treatment. Thoracic kyphosis initially decreased by mean 15° and was partially lost during treatment. Lordosis was largely unaltered during treatment. Mean T1-S1 height increased from 30.7 cm (22.7-39.2) to 34.6 cm (27.8-45.1) postop and further increased to 38.5 cm (30.1-48.1) during treatment. This corresponded to a T1-S1 growth rate of 12 mm/year, and positive growth rates were found in all height parameters evaluated. Frontal balance and apical translation improved, whereas sagittal balance was unaltered. Complications occurred in 22/38 patients, and 11/38 had an unintended reoperation. Pulmonary function (FVC and FEV) increased but the relative lung function was unchanged. CONCLUSION: The new growth rod concept provided 3D correction and spinal growth at complication rates comparable with other growth-friendly techniques for EOS, while pulmonary function was preserved. Single magnetic rod distraction was incorporated successfully, replacing surgical elongations.

[Untreated os odontoideum may cause tetraplegia].

This review summarises the present, limited, knowledge of os odontoideum (OO). The prevalence is unknown, and the aetiology is widely debated, though irrelevant to management of the disease. Surgery of symptomatic patients is advocated, as there is more uncertainty about the treatment of asymptomatic patients. Diagnosis is obtained with plain X-ray. However, nowadays MRI and CT scanning are recommended for further clarification and judgement of the severity. Knowledge of OO is important to minimise misjudgement and consequently inappropriate treatment. It is recommended, that patients are examined by highly specialised spine doctors before further cervical manipulation due to the high risk of instability with potentially severe consequences.

Does transforaminal lumbar interbody fusion produce leg pain?-Results from a RCT.

BACKGROUND: Transforaminal lumbar interbody fusion (TLIF) is presently the most used method to achieve lumbar interbody fusion worldwide. The special preparation and cage insertion imply a risk of an undesirable side effect in the form of residual neurogenic pain. This issue has not been investigated prior in a randomized clinical trial (RCT) set up. AIM: To test whether TLIFs had a higher incidence of leg pain in comparison to a common instrumented posterolateral fusion (PLF) and to test whether a higher occurrence of leg pain on the ipsilateral side in the TLIF group was present. METHODS: One hundred patients included in a RCT comparing TLIF and PLF fulfilled pain drawings and numeric rating scale (NRS) scale from 0 to 10 preoperatively, after 1 year, and after 2 years. Difference in pain appearance, type, localization, and intensity was compared between groups. RESULTS: A slightly higher number of patients in the TLIF group reported leg pain at 2 years follow-up: no leg pain, 47% (PLF) and 37% (TLIF); unilateral leg pain, 31% (PLF) and 25% (TLIF); bilateral leg pain, 22% (PLF) and 37% (TLIF), p = 0.270. Numbness and pins and needles on the anterior aspect of the lower leg were marked by 10% and 12% of TLIF patients compared to 6% and 4% in PLF patients p = 0.498/0.197. The ipsilateral side of cage insertion in the TLIF group was not a place for new leg pain compared to the contralateral side. CONCLUSION: The special surgical preparation used in TLIFs does not result in the development of new ipsilateral leg pain. However, a higher percentage of the patients in the TLIF group had new leg pain in comparison to PLF after 2 years.

Transforaminal lumbar interbody fusion (TLIF) versus posterolateral instrumented fusion (PLF) in degenerative lumbar disorders: a randomized clinical trial with 2-year follow-up.

PURPOSE: The aim of the present study was to analyze outcome, with respect to functional disability, pain, fusion rate, and complications of patients treated with transforaminal lumbar interbody fusion (TLIF) in compared to instrumented poserolateral fusion (PLF) alone, in low back pain. Spinal fusion has become a major procedure worldwide. However, conflicting results exist. Theoretical circumferential fusion could improve functional outcome. However, the theoretical advantages lack scientific documentation. METHODS: Prospective randomized clinical study with a 2-year follow-up period. From November 2003 to November 2008 100 patients with severe low back pain and radicular pain were randomly selected for either posterolateral lumbar fusion [titanium TSRH (Medtronic)] or transforaminal lumbar interbody fusion [titanium TSRH (Medtronic)] with anterior intervertebral support by tantalum cage (Implex/Zimmer). The primary outcome scores were obtained using Dallas Pain Questionnaire (DPQ), Oswestry disability Index, SF-36, and low back pain Rating Scale. All measures assessed the endpoints at 2-year follow-up after surgery. RESULTS: The overall follow-up rate was 94 %. Sex ratio was 40/58. 51 patients had TLIF, 47 PLF. Mean age 49(TLIF)/45(PLF). No statistic difference in outcome between groups could be detected concerning daily activity, work leisure, anxiety/depression or social interest. We found no statistic difference concerning back pain or leg pain. In both the TLIF and the PLF groups the patients had significant improvement in functional outcome, back pain, and leg pain compared to preoperatively. Operation time and blood loss in the TLIF group were significantly higher than in the PLF group (p < 0.001). No statistic difference in fusion rates was detected. CONCLUSIONS: Transforaminal interbody fusion did not improve functional outcome in patients compared to posterolateral fusion. Both groups improved significantly in all categories compared to preoperatively. Operation time and blood loss were significantly higher in the TLIF group.

Failure modes in conservative and surgical management of infectious spondylodiscitis.

PURPOSE AND METHODS: We reviewed the management, failure modes, and outcomes of 196 patients treated for infectious spondylodiscitis between January 1, 2000 and December 31, 2010, at the Spinal Unit, Aarhus University Hospital, Aarhus, Denmark. Patients with infectious spondylodiscitis at the site of previous spinal instrumentation, spinal metastases, and tuberculous and fungal spondylodiscitis were excluded. RESULTS: Mean age at the time of treatment was 59 (range 1-89) years. The most frequently isolated microorganism was Staphylococcus aureus. The lumbosacral spine was affected in 64% of patients and the thoracic in 21%. In 24% of patients, there were neurologic compromise, four had the cauda equina syndrome and ten patients were paraplegic. Ninety-one patients were managed conservatively. Treatment failed in 12 cases, 7 patients required re-admission, 3 in-hospital deaths occurred, and 5 patients died during follow-up. Posterior debridement with pedicle screw instrumentation was performed in 75, without instrumentation in 19 cases. Seven patients underwent anterior debridement alone, and in 16 cases, anterior debridement was combined with pedicle screw instrumentation, one of which was a two-stage procedure. Re-operation took place in 12 patients during the same hospitalization and in a further 12 during follow-up. Two in-hospital deaths occurred, and five patients died during follow-up. Patients were followed for 1 year after treatment. Eight (9%) patients treated conservatively had a mild degree of back pain, and one (1%) patient presented with mild muscular weakness. Among surgically treated patients, 12 (10%) had only mild neurological impairment, one foot drop, one cauda equine dysfunction, but 4 were paraplegic. Twenty-seven (23%) complained of varying degrees of back pain. CONCLUSIONS: Conservative measures are safe and effective for carefully selected patients without spondylodiscitic complications. Failure of conservative therapy requires surgery that can guarantee thorough debridement, decompression, restoration of spinal alignment, and correction of instability. Surgeons should master various techniques to achieve adequate debridement, and pedicle screw instrumentation may safely be used if needed.

Predictive value of Tokuhashi scoring systems in spinal metastases, focusing on various primary tumor groups: evaluation of 448 patients in the Aarhus spinal metastases database.

STUDY DESIGN: We conducted a prospective cohort study of 448 patients with spinal metastases from a variety of cancer groups. OBJECTIVE: To determine the specific predictive value of the Tokuhashi scoring system (T12) and its revised version (T15) in spinal metastases of various primary tumors. SUMMARY OF BACKGROUND DATA: The life expectancy of patients with spinal metastases is one of the most important factors in selecting the treatment modality. Tokuhashi et al formulated a prognostic scoring system with a total sum of 12 points for preoperative prediction of life expectancy in 1990 and revised it in 2005 to a total sum of 15 points. There is a lack of knowledge about the specific predictive value of those scoring systems in patients with spinal metastases from a variety of cancer groups. METHODS: We included 448 patients with vertebral metastases who underwent surgical treatment during November 1992 to November 2009 in Aarhus University Hospital NBG. Data were retrieved from Aarhus Metastases Database. Scores based on T12 and T15 were calculated prospectively for each patient. We divided all the patients into different groups dictated by the site of their primary tumor. Predictive value and accuracy rate of the 2 scoring systems were compared in each cancer group. RESULTS: Both the T12 and T15 scoring systems showed statistically significant predictive value when the 448 patients were analyzed in total (T12, P < 0.0001; T15, P < 0.0001). The accuracy rate was significantly higher in T15 (P < 0.0001) than in T12. The further analyses by primary cancer groups showed that the predictive value of T12 and T15 was primarily determined by the prostate (P = 0.0003) and breast group (P = 0.0385). Only T12 displayed predictive value in the colon group (P = 0.0011). Neither of the scoring systems showed significant predictive value in the lung (P > 0.05), renal (P > 0.05), or miscellaneous primary tumor groups (P > 0.05). The accuracy rate of prognosis in T15 was significantly improved in the prostate (P = 0.0032) and breast group (P < 0.0001). CONCLUSION: Both T12 and T15 showed significant predictive value in patients with spinal metastases. T15 has a statistically higher accuracy rate than T12. Among the various cancer groups, the 2 scoring systems are especially reliable in prostate and breast metastases groups. T15 is recommended as superior to T12 because of its higher accuracy rate.

Distal adding-on phenomenon in Lenke 1A scoliosis: risk factor identification and treatment strategy comparison.

STUDY DESIGN: Retrospective study. OBJECTIVE: To identify risk factors for the presence of distal adding-on in Lenke 1A scoliosis and compare different treatment strategies. SUMMARY OF BACKGROUND DATA: Distal adding-on is often accompanied by unsatisfactory clinical outcome and high risk of reoperation. However, very few studies have focused on distal adding-on and its attendant risk factors and optimal treatment strategies remain controversial. METHODS: All surgically treated patients with adolescent idiopathic scoliosis were retrieved from a single institutional database. Inclusion criteria included: (1) Lenke 1A scoliosis patients treated with posterior pedicle screw-only constructs, (2) minimum 1-year radiographic follow-up. Distal adding-on was defined as a progressive increase in the number of vertebrae included distally within the primary curve combined with either an increase of more than 5 mm in deviation of the first vertebra below instrumentation from the center sacral vertical line (CSVL), or an increase of more than 5° in the angulation of the first disc below the instrumentation at 1 year follow-up. Wilcoxon rank sum test, Fisher exact test, and Spearman correlation test were used to identify the risk factors for adding-on. A multiple logistic regression model was built to identify independent predictive factor(s). Risk factors included: (1) age at surgery; (2) preoperative Cobb angle; (3) correction rate; (4) the gap difference of stable vertebra-lowest instrumented vertebra (SV-LIV), neutral vertebra-lowest instrumented vertebra (NV-LIV), and end vertebra-lowest instrumented vertebra (EV-LIV). Gap difference means, for example, if SV is at L2 and LIV is at Th12, then the difference of SV-LIV is 2; (5) the preoperative deviation of LIV+1 (the first vertebra below the instrumentation) from the CSVL (the vertical line that bisects proximal sacrum). Five methods for determining LIV were compared in both the adding-on group and no adding-on group. RESULTS: Out of the 278 patients reviewed, 45 met the inclusion criteria; 23 of these met the definition for distal adding-on, and were included in the adding-on group. The remaining 22 patients were included in the no adding-on group. The average follow-up was 3.6 years. Age, SV-LIV difference, EV-LIV difference, and LIV+1 deviation from CSVL were significantly different (P<0.05) between the two groups, and were also found to be significantly correlated with the presence of adding-on (P<0.05). Preoperative Cobb angle, correction rate, and NV-LIV difference were not found to be affiliated with the presence of adding-on. Multiple logistic regression results indicated that preoperative LIV+1 deviation from CSVL was an independent predictive factor. Among the five methods, choosing EV as LIV was nearly unable to prevent distal adding-on; choosing EV+1 as LIV resulted in fusing many more segments than necessary; only choosing DV as LIV showed satisfactory outcome from both perspectives. CONCLUSION: In Lenke 1A type scoliosis, the selection of LIV is highly correlated with the presence of adding-on; incidence increases dramatically when the preoperative LIV+1 deviation from CSVL is more than 10 mm. Choosing DV (the first vertebra in cephalad direction from sacrum with deviation from CSVL of more than 10 mm) as LIV may provide the best outcome as it not only prevents adding-on but also conserves more lumbar motion.

The predictive value of pain drawings in lumbar spinal fusion surgery.

BACKGROUND CONTEXT: Pain drawings have been used extensively in spine surgery. It has been associated with inferior outcome after disc and stenosis surgery. Results regarding the predictive value in fusion surgery have been conflicting. PURPOSE: To evaluate the predictive value of pain drawings in relation to outcome after lumbar spinal fusion. To investigate if there are differences between spondylolisthesis patients and patients with degenerative disease as well as between patients with or without radicular pain. STUDY DESIGN: Prospective clinical cohort with a minimum of 1-year follow-up. PATIENT SAMPLE: One hundred thirty-five patients undergoing lumbar spinal fusion. Fifty-seven men and 78 women, mean age 44 years (range 21-59 years). OUTCOME MEASURES: Dallas Pain Questionnaire (DPQ), Low Back Pain Rating Scale (LBPRS) pain index and patient satisfaction. Minimal clinical important difference was defined for the LBPRS score. METHODS: Pain drawings were classified, using the visual inspection method, as organic or nonorganic and correlated to outcomes. Multivariate adjustment for several possible confounding variables was done using logistic regression analysis. RESULTS: Thirty-three percent of the drawings were classified as nonorganic. Nonorganic drawings were associated with significantly higher DPQ and LBPRS scores preoperatively and at follow-up. Differences between organic and nonorganic drawings were larger in spondylolisthesis patients than in patients with degenerative disorders. Nonorganic pain drawings were associated with poorer outcome in patients with low back pain and radicular symptoms, however, not in patients without radicular symptoms. A nonorganic pain drawing predicted negative patient satisfaction with odds ratio (OR) 3.01 (95% confidence interval (CI): 1.14-8.55, p=.027) but had no significant predictive value with respect to improvement in the LBPRS pain index OR 1.92 (95% CI: 0.82-4.47, p=.132). CONCLUSIONS: A nonorganic pain drawing was a significant risk factor for inferior outcome after spinal fusion surgery. The predictive value did not allow for patient selection.

Fusion mass bone quality after uninstrumented spinal fusion in older patients.

Older people are at increased risk of non-union after spinal fusion, but little is known about the factors determining the quality of the fusion mass in this patient group. The aim of this study was to investigate fusion mass bone quality after uninstrumented spinal fusion and to evaluate if it could be improved by additional direct current (DC) electrical stimulation. A multicenter RCT compared 40 and 100 µA DC stimulation with a control group of uninstrumented posterolateral fusion in patients older than 60 years. This report comprised 80 patients who underwent DEXA scanning at the 1 year follow-up. The study population consisted of 29 men with a mean age of 72 years (range 62-85) and 51 women with a mean age of 72 years (range 61-84). All patients underwent DEXA scanning of their fusion mass. Fusion rate was assessed at the 2 year follow-up using thin slice CT scanning. DC electrical stimulation did not improve fusion mass bone quality. Smokers had lower fusion mass BMD (0.447 g/cm(2)) compared to non-smokers (0.517 g/cm(2)) (P = 0.086). Women had lower fusion mass BMD (0.460 g/cm(2)) compared to men (0.552 g/cm(2)) (P = 0.057). Using linear regression, fusion mass bone quality, measured as BMD, was significantly influenced by gender, age of the patient, bone density of the remaining part of the lumbar spine, amount of bone graft applied and smoking. Fusion rates in this cohort was 34% in the control group and 33 and 43% in the 40 and 100 µA groups, respectively (not significant). Patients classified as fused after 2 years had significant higher fusion mass BMD at 1 year (0.592 vs. 0.466 g/cm(2), P = 0.0001). Fusion mass bone quality in older patients depends on several factors. Special attention should be given to women with manifest or borderline osteoporosis. Furthermore, bone graft materials with inductive potential might be considered for this patient population.

The effect of electrical stimulation on lumbar spinal fusion in older patients: a randomized, controlled, multi-center trial: part 1: functional outcome.

STUDY DESIGN: Randomized, controlled, multi-center trial. OBJECTIVE: To investigate the effect of direct current (DC) electrical stimulation on functional and clinical outcome after lumbar spinal fusion in patients older than 60 years. SUMMARY OF BACKGROUND DATA: Older patients have increased complication rates after spinal fusion surgery. Treatments which have the possibility of enhancing functional outcome and fusion rates without lengthening the procedure could prove beneficial. DC-stimulation of spinal fusion has proven effective in increasing fusion rates in younger and "high risk" patients, but functional outcome measures have not been reported. METHODS: A randomized, clinical trial comprising 5 orthopedic centers. The study included a total of 107 patients randomized to uninstrumented posterolateral lumbar spinal fusion with or without DC-stimulation. Functional outcome was assessed using Dallas Pain Questionnaire, SF-36, Low Back Pain Rating Scale pain index, and walking distance. RESULTS: Follow-up after 1 year was 95/107 (89%). DC-stimulated patients had significant better outcome in 3 of 4 categories in the Dallas Pain Questionnaire, better SF-36 scores (not significantly), but no difference in pain scores were observed. Median walking distance at latest follow-up was better in the stimulated group (not significant). Walking distance was significantly associated with functional outcome. There was no difference in any of the functional outcome scores between patients who experienced a perioperative complication and those without complications. CONCLUSION: The achievement of a good functional outcome was heavily dependent on the obtained walking distance. DC-stimulated patients tended to have better functional outcome as compared to controls. No negative effects of perioperative complications could be observed on the short-term functional outcome.

The effect of electrical stimulation on lumbar spinal fusion in older patients: a randomized, controlled, multi-center trial: part 2: fusion rates.

STUDY DESIGN: Randomized, controlled, multi-center trial. OBJECTIVE: To investigate the effect of direct current (DC) electrical stimulation on fusion rates after lumbar spinal fusion in patients older than 60 years. SUMMARY OF BACKGROUND DATA: Older patients have increased complication rates after spinal fusion surgery. Treatments which have the possibility of enhancing functional outcome and fusion rates without lengthening the procedure could prove beneficial. DC-stimulation of spinal fusion has proven effective in increasing fusion rates in younger and "high risk" patients, but little information exist on the effect in older patients. METHODS: A randomized clinical trial comprising 5 orthopedic centers. The study included a total of 107 patients randomized to uninstrumented posterolateral lumbar spinal fusion with or without DC-stimulation. Fusion rate was assessed at 2 year follow-up using thin slice CT. Functional outcome was assessed using Dallas Pain Questionnaire and Low Back Pain Rating Scale pain index. RESULTS.: Available follow-up after 2 years was 89% (84 of 95 patients). Fusion rates were surprisingly low. DC-stimulation had no effect on fusion rate: 35% versus 36% in controls. Other factors associated with low fusion rates were female gender (32% vs. 42% in males, P = 0.050) and smoking (21% vs. 42% in nonsmokers, P = 0.079). Patients who achieved a solid fusion as determined by CT had superior functional outcome and pain scores at their latest follow-up. CONCLUSION: Thin slice CT revealed very high nonunion rates after uninstrumented spinal fusion in older patients. DC-stimulation was not effective in increasing fusion rates in this patient population. The achievement of a solid fusion was associated with superior functional outcome.