Validity of a one-item drawing-based instrument to assess trunk deformity perception in kyphotic deformities.

INTRODUCTION: Body image and trunk appearance perception are two crucial attributes in determining the quality of life of individuals with spinal deformities. The Trunk Appearance Perception Scale (TAPS) is a drawing-based instrument used to evaluate this feature. The TAPS does not include a sagittal view of the trunk so it is never been used to assess trunk deformity perception in hyperkyphotic patients. This study aims to analyze the effect of introducing a new drawing on the TAPS scale representing the trunk view in the sagittal plane. PATIENTS: 170 non-surgical patients were included (mean age 16.9 years and 77.4% women) distributed in three groups. CONTROL group (no deformity): 22 cases; KYPHOSIS group (sagittal deformity): 49 cases and SCOLIOSIS group (coronal deformity): 99 cases (mean Cobb 42.4º). METHOD: Cross-sectional study. A new drawing (TAPS4) was designed to represent the deformity in the sagittal plane with five response options. Clinical (SRS-22 and TAPS 4-items) and radiological (kyphosis T4-T12) data were collected in all patients. The statistical analysis consisted in determining for each group the internal consistency of the 3-items TAPS vs 4-items TAPS, as well as the discriminant validity (correlation with kyphosis magnitude) and convergent validity (correlation with the SRS-22 image subscale). In addition, test-retest reliability of new item 4 was determined in a subgroup of 30 kyphotic patients. During control visit, the patients received a complete physical examination and a full-spine AP and lateral X-ray in standing position using a low-radiation technique and fulfilled instruments TAPS 4 items and SRS-22r. RESULTS: The three groups were found to have statistically significant differences in the magnitude of kyphosis, quality of life, body image perception, the 3-items TAPS, 4-items TAPS and new item 4 score. The addition of the item 4 to TAPS 3 items did not cause a significant change in the internal consistency of the scales (Cronbach's alpha) (TAPS 3-items 0.8 vs. TAPS 4-items 0.8). Kyphosis magnitude was not correlated with the 3-items TAPS and 4-items TAPS scores; however, in the KYPHOSIS group, a significant negative correlation was observed between kyphosis and item 4 (Rho = - 0.4, p = 0.0001). A significant correlation was found in all groups between TAPS 3-items and TAPS 4-items and SRS-22 image domain; the correlation between item 4 and SRS-22 body image domain was 0.3 in the Scoliosis group and 0.7 in the Kyphosis group. CONCLUSIONS: The 4-items TAPS scale does not provide advantages in the assessment of trunk deformity over the 3-items scale. However, in patients with kyphosis, the item 4 (Kypho-TAPS) alone is a valid and reliable instrument to monitor the perception of the trunk deformity.

Thromboprophylaxis in elective spinal surgery: A protocol for systematic review.

BACKGROUND: Venous thromboembolism (VTE) is a serious, sometimes life-threatening complication that can occur following spine surgery. The incidence of VTE, and the optimal type and timing of thromboprophylaxis for this complication in elective spine surgery is a matter of debate. OBJECTIVE: To perform a systematic review with the aim of clarifying the efficacy and adverse effects of mechanical and chemical prophylaxis for preventing thromboembolic complications in elective spine surgery for conditions other than trauma and malignant disease. METHODS/DESIGN: A search strategy of related articles up to March 2018 was designed and executed in Medline and Embase. PATIENTS: adolescents (>10 years) and adults undergoing elective surgery for spinal deformity or degenerative disease (from C1 to S1). INTERVENTION: Perioperative mechanical and chemical thromboprophylaxis. Studies could be randomized controlled trials or observational studies that reported data on any relevant clinical outcomes. RESULTS: In total, 2451 uniquecitations were identified and 35 studies were ultimately included in the systematic review. The overall mean incidence of complications was 3.7% for deep venous thrombosis, 0.0% for pulmonary embolism, and 3.7% for bleeding in chemoprophylaxis group; 2.9% for deep venous thrombosis, 0.4% for pulmonary embolism and 0.0% for bleeding in mechanoprophylaxis; and 0.7% for deep venous thrombosis, 0.1% for pulmonary embolism and 0.2% for bleeding in mixed prophylaxis group with no specific data on these rates for the type of patient and type and location of surgery. None of the articles retrieved provided information on the adolescent population. DISCUSSION AND CONCLUSIONS: The poor design and high variability among the studies regarding characteristics of study population, details of interventions, and definitions of outcomes, determines a low quality of the available evidence and limits the interpretation of the results. We were unable to identify a clear advantage of one type of thromboprophylaxis over the other, although there was an increased risk of bleeding with chemoprophylaxis, which could favor the use of mechanoprophylaxis in this scenario.

Author Correction: Precision and safety of Multilevel Cervical Transpedicular Screw Fixation with 3D Patient-Specific Guides; A Cadaveric Study.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Precision and safety of Multilevel Cervical Transpedicular Screw Fixation with 3D Patient-Specific Guides; A Cadaveric Study.

The aim is to design a patient-specific instrument (PSI) for multilevel cervical pedicle screw placement from C2 to C7, as well as verifying reliability and reproducibility. Computed tomography (CT) scans were obtained from 7 cadaveric cervical spines. Using Mimics software, semiautomatic segmentation was performed for each cervical spine, designing a 3D cervical spine bone model in order to plan transpedicular screw fixation. A PSI was designed according to the previously cited with two cannulated chimneys to guide the drill. The guides were 3D printed and surgeries performed at the laboratory. Postoperative scans were obtained to study screw placement. Sixty-eight transpedicular screws were available for study. 61.8% of all screws were within the pedicle or partially breached <4 mm. No differences were observed between cervical levels. None of these screws had neurovascular injury. Of the 27 screws with a grade 3 (screw outside the pedicle; 39.7%), only 2 had perforation of the transverse foramen and none of them would have caused a neural injury. In conclusion, multilevel PSI for cervical pedicle screw is a promising technology that despite showing improvements regarding free-hand technique requires further studies to improve the positioning of the PSI and their accuracy.

Viability and long-term survival of short-segment posterior fixation in thoracolumbar burst fractures.

BACKGROUND CONTEXT: Short-segment pedicle screw instrumentation constructs for the treatment of thoracolumbar fractures gained popularity in the 1980s. The load-sharing classification (LSC) is a straightforward way to describe the extent of bony comminution, amount of fracture displacement, and amount of correction of kyphotic deformity in a spinal fracture. There are no studies evaluating the relevance of fracture comminution/traumatic kyphosis on the long-term radiologic outcome of burst fractures treated by short-segment instrumentation with screw insertion in the fractured level. PURPOSE: To evaluate the efficacy of the six-screw construct in the treatment of thoracolumbar junction burst fractures and the influence of the LSC score on the 2-year radiologic outcome. STUDY DESIGN: Case series of consecutive patients of a single university hospital. PATIENT SAMPLE: Consecutive patients from one university hospital with nonosteoporotic thoracolumbar burst fractures. OUTCOME MEASURES: Being a radiology-based study, the outcome measures are radiologic parameters (regional kyphosis [RK], local kyphosis, and thoracolumbar kyphosis [TLK]) that evaluate the degree and loss of correction. METHODS: Retrospective analysis of all consecutive patients with nonosteoporotic thoracolumbar burst fractures managed with a six-screw construct in a single university hospital, with more than 2 years' postoperative follow-up. RESULTS: Eighty-six patients met the inclusion criteria, and 72 (83.7%) with available data were ultimately included in the study. The sample included 53 men and 19 women, with a mean (standard deviation [SD]) age of 35.6 years (14.4 years) at the time of surgery. Mean LSC score was 6.3 (SD 1.6, range 3-9). Forty-four of 62 (70.9) fractures had a score greater than 6. Mean (SD) RK and TLK deteriorated significantly during the first 6 months of follow-up: 2.90° (4.54°) p=.005 and 2.78° (6.45°) p=.069, respectively. Surgical correction correlated significantly (r=0.521, p<.0001) with the time elapsed until surgery. Loss of surgical correction (postoperative to 6-month RK and TLK increase) correlated significantly with the LSC score (r=0.57, p=.004; r=0.51, p=.022, respectively). Further surgery because of correction loss was not required in any case. CONCLUSIONS: The six-screw construct is effective for treating thoracolumbar junction burst fractures. The medium-to-long-term loss of correction is affected by the amount of bony comminution of the fracture, objectified through the LSC score.

Poor outcomes and satisfaction in adolescent idiopathic scoliosis surgery: the relevance of the body mass index and self-image.

INTRODUCTION AND AIM: The purpose of this study was to evaluate patients with adolescent idiopathic scoliosis (AIS) to determine whether a low body mass index (BMI) influences surgery outcomes and satisfaction. METHODS: There were 39 patients in this prospective 3-year cohort study. The BMI, Cobb angle, the Body Shape Questionnaire 14 (BSQ-14), the Scoliosis Research Society Questionnaire 22 (SRS-22) and eight satisfaction questions results were obtained. Having a BMI greater than or less than 18 kg/m(2) was used as a determiner to allocate patients to groups. As a low BMI is related to the presence of a disturbance in body perception, patients were also dichotomized by using the BSQ-14. RESULTS: All scales were worse in both slimmer patients and the group with a body perception disorder. The group with a BMI <18 kg/m(2) obtained a total of 82.31 points in the SRS-22, and it was 93.45 points for the group with a BMI >18 kg/m(2) (p = 0.001). In terms of satisfaction, the percentage of patients that would undergo surgery again was 30.8 vs 69.2 % (p = 0.054). Patients with an alteration of physical perception obtained a total SRS-22 of 82.90 points versus 96.10 points in the control group (p < 0.001). No differences in terms of the Cobb correction (p = 0.29) or the percentage of correction (p = 0.841) were found in any case. CONCLUSION: The alteration of physical perception and a low BMI negatively affect the outcomes in AIS surgery, regardless of the curve magnitude and the percentage of correction. Considerable care should be taken in recommending surgical correction to these patients.

Body image in idiopathic scoliosis: a comparison study of psychometric properties between four patient-reported outcome instruments.

BACKGROUND: Four patient-reported outcome (PRO) instruments are commonly used to assess body image in idiopathic scoliosis (IS): the Quality of Life Profile for Spinal Deformities (QLPSD), SRS-22 Self-Image scale, Spinal Appearance Questionnaire (SAQ), and Trunk Appearance Perception Scale (TAPS). The aim of this study is to compare the psychometric properties of these instruments in patients with IS and report the translational/cultural adaptation of the SAQ to Spanish. METHODS: The four instruments in a Spanish version were administered to 80 patients with IS aged 10 to 40 years old. The sample was stratified according to scoliosis magnitude (less and more than 45º). Analysis was also conducted for age groups. The psychometric properties studied included convergent and divergent construct validity, as well as internal consistency. Convergent validity was evaluated by correlation analysis between the self-image instruments and Cobb angle. Divergent validity was assessed with correlation analysis between PRO scores and SRS-22 dimensions scores such as Function, Pain and Mental Health. RESULTS: In the overall sample, each of the PRO instruments demonstrated high internal consistency (QLPSD Body Image, α = 0.80; SRS-22 Self Image, α = 0.78; SAQ, α = 0.89; TAPS, α = 0.87), also both for younger and adult patients subgroups. Correlation with curve magnitude was significant for each of the four scales. However, the correlation was higher for the pictorial scales (SAQ Appearance r = 0.61, TAPS r = -0.62) than for the textual scales (QLPSD-bi r = 0.36, SRS-22 Self-Image scale r = -0.41). In the younger group, correlation between Cobb angle and textual scales (QLPSD-bi and SRS-22 Self-Image Scale) was not significant. Body Image scales showed significant correlations with SRS-22 Pain, Function and Mental Health dimensions. CONCLUSIONS: All four instruments tested have good psychometric properties. Pictorial scales (SAQ Appearance and TAPS) correlated better with the radiological magnitude of the curve and this correlation is independent of age. Unexpectedly, all four scales demonstrated significant correlations with non-body image dimensions and the divergent hypothesis was not confirmed. Globally, pictorial scales showed slightly better construct validity to test body image perception than textual scales.

Body composition in adolescent idiopathic scoliosis.

STUDY DESIGN: A controlled prospective cross-sectional case study. OBJECTIVE: To investigate body mass index (BMI) and corporal composition in girls with adolescent idiopathic scoliosis (AIS) and compare them with a normal population matched by sex and age. There is controversy as to whether there are real anthropometric alterations in patients with AIS. Relative to the weight or the BMI, some studies find differences and other studies do not detect them. AIS and anorexia nervosa (AN) make their debut during adolescence and both may be associated with an alteration of their subjective physical perception. Some authors propose a link between AIS and AN supported both by an alteration of physical perception and lower BMI. No studies on body composition in AIS have been published. METHODS: Adolescent idiopathic scoliosis patient surgery candidates during 2008 were studied. Body composition was evaluated using the bioelectrical impedance analysis (Bodystat, Isle of Man, UK). A study population of more than 5,000 patients that was published by Kyle et al. (Nutrition 17:534-541, 2001) was chosen as a control (group 1). Another control group (group 2) of healthy volunteers matched by sex and age was selected among a school age and university population in Barcelona, Spain. A variance analysis was used to analyze differences between the mean values of the control group 1, the European control group, and the AIS patient surgery candidates (Epiinfo 6.2001). Comparisons between the AIS patients and control group 2 were performed with the T Student test of unpaired samples using the SPSS 15.0 (Statistical Package Social Science) software. RESULTS: Twenty-seven women with a mean age of 17.4 years. BMI was 18.9 kg/m(2) (SD 1.7; 95 % CI 18.31-19.73). In the variance analysis, a significant difference between AIS and group 1 in BMI was observed (21.0 vs. 18.9, p = 0.000004); fat-free mass (FFM = 42.6 vs. 38.9, p = 0.0000009) and fat mass (FM = 15.6 vs. 13.7, p = 0.03). Significant differences in BMI (22.13 vs. 18.9, p = 0.001; 95 % CI difference 1.85-4.60), fat mass index (FMi = 7.17 vs. 4.97, p = 0.000; 95 % CI difference 1.36-3.05) and fat-free mass index (FFMi = 14.95 vs. 13.09, p = 0.001; 95 % CI difference 0.26-1.86) between AIS and group 2 were also seen. CONCLUSION: The conclusion is that there is a real alteration of body composition in AIS. The BMI, FFMi and FMi are lower than in the general population in the series under study.

How do idiopathic scoliosis patients who improve after surgery differ from those who do not exceed a minimum detectable change?

INTRODUCTION: The minimum detectable change (MDC) of the SRS-22 subtotal score is 6.8 points. With the use of this value, patients who have undergone surgery for idiopathic scoliosis can be dichotomized into two groups: the successful (S) group (those who have reached or exceeded this limit) and the unsuccessful (Un-S) group (those in whom the change was smaller). The aim of this study was to analyze the clinical and radiological differences between these patient groups, as well as those related to the surgical technique. MATERIAL AND METHODS: The study included 91 patients (77 women and 14 men, mean age 18.1 years). All patients completed the SRS-22 questionnaire preoperatively and at follow-up (mean 45.6 months). In addition, radiological and surgical data were collected: levels instrumented, number of fused vertebrae, and use of thoracoplasty. RESULTS: Based on the MDC of the SRS-22 subtotal score, patients were assigned to the Un-S group (44 cases, 48.4%) or S group (47 cases). Groups were similar in age, sex, number of fused vertebrae, percentage of patients who underwent thoracoplasty, and the upper and lower instrumented levels. The magnitude of the major curve and percentage of correction after surgery were also similar (Un-S group 62.3º, 53.2%; S group 64.3º, 49.9%). As compared to Un-S group, S patients had a poorer preop score in all the SRS-22 domains, and a clinically significant postop improvement in pain, perceived body image, mental health, and subtotal score. In contrast, the Un-S group showed a worsening of pain, function, mental health, and subtotal score, and a clinically nonsignificant improvement in perceived body image on the follow-up questionnaire. There were no significant differences in the satisfaction domain score between groups (4.36 vs. 4.62). On ROC curve analysis, a preop subtotal score of 74 points predicted allocation to the S or Un-S group at follow-up with 79% sensitivity and 76% specificity. CONCLUSION: The preop subtotal score of the SRS-22 is a good predictor of the clinical response to surgery.

Antifibrinolytic therapy in complex spine surgery: a case-control study comparing aprotinin and tranexamic acid.

A case-control study was performed to determine the impact of aprotinin or tranexamic acid use on reducing intraoperative blood loss and transfusion needs in complex spine surgery. Sixty-nine patients undergoing complex spine surgery received aprotinin or tranexamic acid. The aprotinin group contained 30 patients (8 men and 22 women) and the tranexamic acid group 39 patients (11 men and 28 women). The following variables were recorded: duration of surgery, number of levels fused, intraoperative and total blood loss, and number of blood units transfused (autologous and allogenic). In addition, various parameters related to blood loss in this type of surgery were calculated. The groups differed with regard to duration of surgery (aprotinin 662 min vs tranexamic acid 448 min, P<.001) and number of levels fused (aprotinin 11.2 vs tranexamic acid 7.6, P=.004). There were no significant differences in intraoperative blood loss (aprotinin 2118 mL vs tranexamic acid 1608 mL, P=.066) or total blood loss (aprotinin 3312 mL vs tranexamic acid 2627 mL, P=.056). Statistical differences were found for the number of autologous blood units transfused (aprotinin 2.2 vs tranexamic acid 1.3 P=.047) and total units transfused (aprotinin 4.1 vs tranexamic acid 2.6, P=.008). Blood loss per hour of surgery, transfused units per level fused, and transfused units per hour of surgery were similar in the 2 groups. Significant differences were found for intraoperative blood loss per fusion level (aprotinin 228 mL vs tranexamic acid 428, P=.025) and total blood loss per fusion level (aprotinin 360 mL vs tranexamic acid 638 mL, P=.01). Analysis of the applied geometric mean showed that aprotinin reduced total blood loss by 16.4% and total number of blood units transfused by 12.4% as compared to tranexamic acid, although statistical significance was not reached. The type of antifibrinolytic used did not have a significant impact on the main outcome variables of the study.

Psychometric characteristics of the Spanish version of instruments to measure neck pain disability.

BACKGROUND: The NDI, COM and NPQ are evaluation instruments for disability due to NP. There was no Spanish version of NDI or COM for which psychometric characteristics were known. The objectives of this study were to translate and culturally adapt the Spanish version of the Neck Disability Index Questionnaire (NDI), and the Core Outcome Measure (COM), to validate its use in Spanish speaking patients with non-specific neck pain (NP), and to compare their psychometric characteristics with those of the Spanish version of the Northwick Pain Questionnaire (NPQ). METHODS: Translation/re-translation of the English versions of the NDI and the COM was done blindly and independently by a multidisciplinary team. The study was done in 9 primary care Centers and 12 specialty services from 9 regions in Spain, with 221 acute, subacute and chronic patients who visited their physician for NP: 54 in the pilot phase and 167 in the validation phase. Neck pain (VAS), referred pain (VAS), disability (NDI, COM and NPQ), catastrophizing (CSQ) and quality of life (SF-12) were measured on their first visit and 14 days later. Patients' self-assessment was used as the external criterion for pain and disability. In the pilot phase, patients' understanding of each item in the NDI and COM was assessed, and on day 1 test-retest reliability was estimated by giving a second NDI and COM in which the name of the questionnaires and the order of the items had been changed. RESULTS: Comprehensibility of NDI and COM were good. Minutes needed to fill out the questionnaires [median, (P25, P75)]: NDI. 4 (2.2, 10.0), COM: 2.1 (1.0, 4.9). Reliability: [ICC, (95%CI)]: NDI: 0.88 (0.80, 0.93). COM: 0.85 (0.75,0.91). Sensitivity to change: Effect size for patients having worsened, not changed and improved between days 1 and 15, according to the external criterion for disability: NDI: -0.24, 0.15, 0.66; NPQ: -0.14, 0.06, 0.67; COM: 0.05, 0.19, 0.92. VALIDITY: Results of NDI, NPQ and COM were consistent with the external criterion for disability, whereas only those from NDI were consistent with the one for pain. Correlations with VAS, CSQ and SF-12 were similar for NDI and NPQ (absolute values between 0.36 and 0.50 on day 1, between 0.38 and 0.70 on day 15), and slightly lower for COM (between 0.36 and 0.48 on day 1, and between 0.33 and 0.61 on day 15). Correlation between NDI and NPQ: r = 0.84 on day 1, r = 0.91 on day 15. Correlation between COM and NPQ: r = 0.63 on day 1, r = 0.71 on day 15. CONCLUSION: Although most psychometric characteristics of NDI, NPQ and COM are similar, those from the latter one are worse and its use may lead to patients' evolution seeming more positive than it actually is. NDI seems to be the best instrument for measuring NP-related disability, since its results are the most consistent with patient's assessment of their own clinical status and evolution. It takes two more minutes to answer the NDI than to answer the COM, but it can be reliably filled out by the patient without assistance. TRIAL REGISTRATION: Clinical Trials Register NCT00349544.

Cardiac tamponade associated with a peripheral vein central venous catheter.

We present a case of cardiac tamponade associated with placement of a central venous catheter (CVC) via a peripheral vein in a 14-year-old girl with idiopathic scoliosis undergoing corrective surgery. A number of complications have been described in association with CVC misplacement. Sporadic cases of cardiac tamponade from this have been reported, but the actual incidence is unknown. Death from cardiac tamponade attributed to CVCs ranges from 65 to 100%. In our patient, cannulation of the pericardiophrenic vein was probably the cause of cardiac tamponade, based on radiological evidence that the initial location of the catheter was near the right atrium and possibly at the outlet of the pericardiophrenic vein. The catheter could have advanced into the vein and then to the pericardial sac with postural changes. The acute clinical course of cardiac tamponade in our patient had potentially lethal hemodynamic repercussions. The main diagnostic test for this condition is echocardiography and the only effective treatment is drainage of the pericardial effusion. Echocardiography should be performed before pericardiocentesis except in life-threatening situations or high clinical suspicion. Although they are rare, it is important to be aware of the potential for CVC complications.

Reliability of retrospective clinical data to evaluate the effectiveness of lumbar fusion in chronic low back pain.

STUDY DESIGN: Patients in whom a posterior spinal fusion instrumentation had been performed to treat low back pain were asked to recall their preoperative clinical status by retrospectively filling out the same 3 self-evaluation scales they had completed before surgery in a prospective fashion. OBJECTIVES: To evaluate the impact of recollection error and compare outcomes using retrospective versus prospective methodologies among a cohort of patients treated with posterior spinal fusion instrumentation. SUMMARY OF BACKGROUND DATA: Literature on spine surgery from 1990 to 2000 shows a greater increase in retrospective studies as compared to randomized controlled trials and other prospective studies. Cross-sectional studies evaluate therapeutic effectiveness by comparing the current condition with the recalled (retrospectively recorded) pretreatment condition. There are no studies analyzing the characteristics of recalled data in a cohort of patients with chronic low back pain treated with posterior spinal fusion instrumentation. METHODS: The preoperative clinical status of 58 patients, 33 women and 25 men, with a mean age of 48.3 years (22-84 years) was assessed prospectively with 3 self evaluation questionnaires and retrospectively at a mean of 37.5 months (2-58 months) after surgery using the same questionnaires. The Wilcoxon test was used to compare prospective and retrospective preoperative data and to compare prospective outcomes with outcomes determined from cross-sectional data. Agreement between prospective and retrospective measures was estimated with intraclass correlation coefficients for absolute agreement and consistency. RESULTS: Comparisons between prospective and recalled data showed significant differences, demonstrating a worse preoperative situation when using retrospective data. Assessment of treatment effectiveness showed that cross-sectional evaluation significantly improved the real surgical outcome. Both absolute agreement and consistency intraclass correlation coefficients showed poor agreement between prospective and cross-sectional data, revealing no systematic bias. Follow-up, age, and gender did not modify agreement and cross-sectional overestimation. CONCLUSIONS: Relying on a patient's recall of preoperative clinical status is not an accurate method to evaluate surgical outcome after posterior spinal fusion instrumentation. Cross-sectional studies may overestimate the effectiveness of surgery.

Transcranial Doppler monitoring during laparoscopic anterior lumbar interbody fusion.

UNLABELLED: We studied the consequences on cerebral hemodynamics of lengthy laparoscopic procedures requiring pneumoperitoneum and head-down positioning. From October 1995 to April 1999, 17 ASA status I or II patients (16 women and 1 man; mean age, 38 yr) were treated with laparoscopic anterior lumbar fusion. Besides standard perioperative monitoring for laparoscopic surgery, the mean blood-flow velocity of both middle cerebral arteries and the pulsatility index were determined by transcranial Doppler ultrasound. Adequate acoustic windows were encountered in 11 of the 17 patients, and the remaining 6 were excluded from the analysis. PaCO(2) and end-tidal CO(2) were maintained within normal limits (<40 mm Hg); ventilation was optimized in all cases. There was a significant increase (P < 0.05) in heart rate and central venous pressure with the change from supine to head-down position in all patients. Transcranial Doppler results for mean middle cerebral artery blood-flow velocity and pulsatility index showed no significant variations at any of the four time points studied during the procedure. There were no technique-related complications, except for moderate postoperative headache in eight patients that resolved with rest and oxygen therapy. We conclude that lengthy laparoscopic procedures in the head-down position performed in otherwise healthy patients do not significantly affect intracranial circulation. IMPLICATIONS: This study assessed the consequences of lengthy laparoscopic surgery with head-down (Trendelenburg) positioning on cerebral blood circulation by transcranial Doppler ultrasound, a noninvasive technique. It is important to investigate whether there are cerebral hemodynamic changes because these may be detrimental to some patients for whom this surgery is considered.

Low fusion rate after L5-S1 laparoscopic anterior lumbar interbody fusion using twin stand-alone carbon fiber cages.

STUDY DESIGN: Prospective study of a cohort of patients who underwent L5-S1 laparoscopic anterior lumbar interbody fusion. OBJECTIVES: To assess the fusion rate and the clinical outcome more than 2 years after L5-S1 laparoscopic anterior lumbar interbody fusion using twin stand-alone carbon-fiber cages. SUMMARY OF BACKGROUND DATA: The first reports on laparoscopic anterior lumbar interbody fusion using stand-alone cages appeared in 1995. Since then several articles have reported contradictory data regarding fusion rate. There are no publications describing the fusion rate of stand-alone lumbar carbon-fiber cages. METHODS: The authors evaluated 12 patients (mean age 36.5 years) in whom endoscopic L5-S1 anterior lumbar interbody fusion was performed using twin stand-alone laparoscopic carbon-fiber cages. Clinical evaluation was carried out prospectively by the use of three self-evaluation scales. Radiologic evaluation was performed by an independent radiologist using dynamic flexion-extension films and CT scans at 6 and 12 months after surgery and subsequently every year until fusion was demonstrated. RESULTS: After a mean follow-up of 36.6 months (range 24-63 months) the clinical condition of the patients was significantly better than their preoperative status: visual analog scale (P < 0.01), Prolo score (P < 0.05), and Waddell Disability Index (P < 0.01). L5-S1 mobility did not exceed 5 degrees in any dynamic study. However, the overall CT scan fusion rate at 2 years of follow-up was 16.6%. Three years after surgery, CT demonstrated fusion in one of five patients. CONCLUSION: Two years after endoscopic L5-S1 anterior lumbar interbody fusion using twin stand-alone laparoscopic carbon-fiber cages, the fusion rate was unacceptably low. However, the clinical outcomes of these patients were significantly improved compared with their preoperative status.