Gait adaptations in low back pain patients with lumbar disc herniation: trunk coordination and arm swing

Patients with chronic non-specific low back pain (LBP) walk with more synchronous (in-phase) horizontal pelvis and thorax rotations than controls. Low thorax–pelvis relative phase in these patients appears to result from in-phase motion of the thorax with the legs, which was hypothesized to affect arm swing. In the present study, gait kinematics were compared between LBP patients with lumbar disc herniation and healthy controls during treadmill walking at different speeds and with different step lengths. Movements of legs, arms, and trunk were recorded. The patients walked with larger pelvis rotations than healthy controls, and with lower relative phase between pelvis and thorax horizontal rotations, specifically when taking large steps. They did so by rotating the thorax more in-phase with the pendular movements of the legs, thereby limiting the amplitudes of spine rotation. In the patients, arm swing was out-of phase with the leg, as in controls. Consequently, the phase relationship between thorax rotations and arm swing was altered in the patients.     

Epidemiology of low back pain in the elderly: correlation with lumbar lordosis

We carried out an epidemiologic study to determine the prevalence of low back pain in elderly Japanese and to examine the correlation with lumbar lordosis in sagittal plane radiographs. Low back pain is an enormous clinical and public health problem. With the increasing use of spinal instrumentation, the measurement of lumbar lordosis is thought to be important. However, in elderly Japanese, the prevalence of low back pain and its correlation with lumbar lordosis is not clear. Five hundred and nine people, aged 50–85 years, were examined, and 489 subjects met our criteria. Clinical findings, physical status, and the visual analogue scale (VAS) of pain were examined in these subjects. Measurements and determination of total lordosis from L1-S1 were made from standing radiographs. Forty-eight percent of the subjects had experienced low back pain within the previous 3 months. Women had low back pain more frequently (P = 0.006). There was a significant difference in lumbar lordosis between the groups with and without low back pain (P = 0.0006). Lumbar lordosis was approximately 4° less in the low back pain group and there was no relationship to age or sex in either group. VAS was significantly inversely correlated with lumbar lordosis (P = 0.025, at rest). The body mass index (BMI) of the low back pain group was higher in women, but the difference was not significant (P = 0.06). In conclusion, lumbar lordosis was defined and its prevalence in elderly Japanese was reported together with VAS and physical data used to compare the two groups. Received: September 6, 2000 / Accepted: February 11, 2001     

Effects of chronic low back pain on trunk coordination and back muscle activity during walking: changes in motor control

Low back pain (LBP) is often accompanied by changes in gait, such as a decreased (preferred) walking velocity. Previous studies have shown that LBP diminishes the normal velocity-induced transverse counter-rotation between thorax and pelvis, and that it globally affects mean erector spinae (ES) activity. The exact nature and causation of these effects, however, are not well understood. The aim of the present study was to examine in detail the effect of walking velocity on global trunk coordination and ES activity as well as their variability to gain further insights into the effects of non-specific LBP on gait. The study included 19 individuals with non-specific LBP and 14 healthy controls. Gait kinematics and ES activity were recorded during treadmill walking at (1) a self-selected (comfortable) velocity, and (2) sequentially increased velocities from 1.4 up to maximally 7.0 km/h. Pain intensity, fear of movement and disability were measured before the experiment. The angular movements of thorax, lumbar and pelvis were recorded in three dimensions. ES activity was recorded with pairs of surface electrodes. Trunk–pelvis coordination and mean amplitude of ES activity were analyzed. In addition, invariant and variant properties of trunk kinematics and ES activity were studied using principal component analysis (PCA). Comfortable walking velocity was significantly lower in the LBP participants. In the transverse plane, the normal velocity-induced change in pelvis–thorax coordination from more in-phase to more antiphase was diminished in the LBP participants, while lumbar and pelvis rotations were more in-phase compared to the control group. In the frontal plane, intersegmental timing was more variable in the LBP than in the control participants, with additional irregular movements of the thorax. Rotational amplitudes were not significantly different between the LBP and control participants. In the LBP participants, the pattern of ES activity was affected in terms of increased (residual) variability, timing deficits, amplitude modifications and frequency changes. The gait of the LBP participants was characterized by a more rigid and less variable kinematic coordination in the transverse plane, and a less tight and more variable coordination in the frontal plane, accompanied by poorly coordinated activity of the lumbar ES. Pain intensity, fear of movement and disability were all unrelated to the observed changes in coordination, suggesting that the observed changes in trunk coordination and ES activity were a direct consequence of LBP per se. Clinically, the results imply that conservative therapy should consider gait training as well as exercises aimed at improving both intersegmental and muscle coordination.     

Functional roles of abdominal and back muscles during isometric axial rotation of the trunk.

Electromyographic (EMG) studies have shown that a large number of trunk muscles are recruited during axial rotation. The functional roles of these trunk muscles in axial rotation are multiple and have not been well investigated. In addition, there is no information on the coupling torque at different exertion levels during axial rotation. The aim of the study was to investigate the functional roles of rectus abdominis, external oblique, internal oblique, latissimus dorsi, iliocostalis lumborum and multifidus during isometric right and left axial rotation at 100%, 70%, 50% and 30% maximum voluntary contractions (MVC) in a standing position. The coupling torques in sagittal and coronal planes were measured during axial rotation to examine the coupling nature of torque at different levels of exertions. Results showed that the coupled sagittal torque switches from nil to flexion at maximum exertion of axial rotation. Generally, higher EMG activities were shown at higher exertion levels for all the trunk muscles. Significant differences in activity between the right and left axial rotation exertions were demonstrated in external oblique, internal oblique, latissimus dorsi and iliocostalis lumborum while no difference was shown in rectus abdominis and multifidus. These results demonstrated the different functional roles of trunk muscles during axial rotation. This is important considering that the abdominal and back muscles not only produce torque but also maintain the spinal posture and stability during axial rotation exertions. The changing coupling torque direction in the sagittal plane when submaximal to maximal exertions were compared may indicate the complex nature of the kinetic coupling of trunk muscles.     

Sitting and low back pain: the positive effect of rotatory dynamic stimuli during prolonged sitting

In this study the effect of dynamic stimuli on low back pain during prolonged sitting was investigated. The pain experience of two groups of 60 subjects with aspecific low back pain was recorded. All subjects were investigated on pain behaviour by the Multidimensional Pain Inventory (MPI) and pain was measured on an open visual analogue scale (VAS). During sitting, one group received dynamic stimuli that were generated by alternating rotations in the horizontal plane of the seat of the chair, with back and arm rests in fixed position. Two different frequencies of rotation were applied in subgroups. The authors concluded that such stimuli, especially of the lower frequency, reduced pain in prolonged sitting. Received: 8 May 1998 Revised: 23 November 1998 Accepted: 28 December 1998     

棘突间动态内固定装置治疗腰痛的临床应用评价

目的 评价采用Coflex棘突间动态内固定植入术治疗腰痛的临床疗效及相关影像学改变.方法 2007年2月至2009年6月,对45例患者行Coflex棘突间内固定植入术,男26例,女19例;年龄45～70岁,平均51.4岁.治疗节段:L4.5 32例,L5S111例,L4.5、L5S1双节段2例.手术采用椎板开窗或部分切除,椎管减压后棘突间植入Coflex装置.按照Oswestry功能障碍指数(Oswestry disabi1ity index,ODI)和日本矫形外科学会(Japanese Orthopaedic Association,JOA)评分评价术前及术后随访时的临床疗效,计算恢复率.同时行影像学观察,包括椎间隙高度和椎间孔形态,手术节段椎体活动度和腰椎生理曲度,手术及相邻节段的MRI信号改变.结果 术后随访时间1O-34个月,平均24个月.ODI由术前62.82±10.42降至末次随访时11.80±3.35;JOA评分由9.00±2.63提高至24.65±1.86;最终疗效评价为显效的患者共40例,显效率为89%.L4.5、L5S1节段术后Cobb角分别为15.1°±3.9°和16.3°±3.8°,均较术前减小,生理曲度改善.L4.5节段椎体活动度(range of motion,ROM)由术前6.5°±1.5°增加至术后8.4°±2.6°,而L5S1节段ROM手术前后没有明显改变.无论是L4.5或是L5S1节段,末次随访时其椎间隙背侧高度、棘突顶距、椎间孔高度和椎间孔面积均较术前显著增加.结论 Coflex棘突间动态内固定中期随访临床疗效显著,并且保留了腰椎生理曲度和节段运动,增加并维持椎间隙高度和椎间孔面积,在手术节段椎间盘修复及防止相邻节段椎间盘退变等方面作用显著.     

棘突间非融合技术在椎间盘源性腰痛中的应用

目的总结棘突间动态稳定系统Wallis治疗椎间盘源性腰痛(discogenic low back pain,DLBP)的中短期临床效果。方法观察2007年～2010年应用Wallis棘突间稳定系统治疗的35例DLBP患者手术前后腰部痛视觉模拟量表(visual analogue scale,VAS)评分,Oswestry功能障碍指数(Oswestry disability index,ODI),病变节段手术前后的活动范围(range of motion,ROM)及椎间隙高度(disc height,DH)的变化。结果所有患者平均随访30个月。腰痛VAS评分由术前的(7.83±1.42)分降至随访时的(2.43±1.33)分,ODI由术前的(66.24±11.38)%减至随访时的(25.69±10.33)%,差异均有统计学意义(P<0.05)。DH术前(9.01±0.59)mm,随访时(9.19±0.53)mm,差异有统计学意义(P<0.05)。ROM由术前的16.3°±1.4°减少到随访时的12.3°±1.3°,差异有统计学意义(P<0.05)。结论 Wallis棘突间动态稳定系统治疗DLBP的中短期疗效满意,能较好地恢复手术节段DH,减少手术节段ROM,预防腰椎不稳,远期疗效尚需进一步随访。     

腰椎Modic改变的MRI定量与下腰痛相关性研究

目的：通过测定MRI T2正中矢状位像上腰椎终板Modic面积改变率分析Modic面积改变率大小与下腰痛程度的相关性。方法：2011年12月至2012年6月,对因下腰痛手术的70例患者进行疼痛和功能评分（JOA、VAS）和MRI检查,男39例,女31例;年龄29～72岁,平均（51.00±11.89）岁。70例中54例有腰椎终板Modic改变,将54例患者按Modic分型标准分为4型：Modic I型15例,ModicⅡ型21例,Modic Ⅲ型11例,Modic混和型7例（由于Modic混合型例数太少未纳入研究排除）.在MRI T2正中矢状位上测量各分型Modic改变面积及对应椎体的面积,两者面积比较得出Modic改变率,对于多节段Modic改变的求比率之和,观察JOA、VAS评分与Modic改变率之间的相关性。结果：ModicⅠ型改变率和JOA评分的相关系数r=-0.308,P=0.048<0.05,两者具有负相关性;与VAS评分的相关系数r=0.428,P=0.021<0.05,两者具有正相关性。ModicⅡ型改变率和JOA评分的相关系数r=-0.375,P=0.043<0.05,两者有负相关性;与VAS评分的相关系数r=0.352,P=0.041<0.05,两者具有正相关性。Modic Ⅲ型面积改变率与下腰痛程度无明显相关性（P>0.05）.结论：下腰痛患者中ModicⅠ、Ⅱ型面积改变率分别与下腰痛的疼痛程度有密切关系,ModicⅢ型面积改变率与下腰痛程度无明显相关性。     

去神经化治疗腰椎关节突关节源性腰痛的有效性与安全性研究

目的:探讨脊神经后内侧支阻滞模拟去神经化治疗腰椎关节突关节源性腰痛的有效性与安全性。方法:自2009年3月至2010年10月,采用脊神经后内侧支阻滞模拟去神经化治疗腰椎关节突关节源性腰痛患者10例,男6例,女4例;年龄41～68岁,平均56.4岁;病程0.5～3年,平均1.2年。每例患者分别进行脊神经后内侧支单支阻滞、双支阻滞、三支阻滞、四支阻滞(分别在C形臂X线透视引导下行病变腰椎关节突关节和(或)上下邻近几个关节行腰脊神经后内侧支阻滞),其中5例双支阻滞时行同位脊神经后内侧支及上位神经阻滞,5例行同位及下位神经阻滞。以相应上关节突与横突根部交界处为靶点。用药均为:0.5%盐酸利多卡因15ml加入确炎舒松-A1ml(10mg/ml)、甲钴铵注射液1ml(500μg)。评价患者阻滞前、阻滞腰脊神经后内侧支单支、双支、3支、4支后腰背部疼痛的VAS评分、致痛关节突关节水平多裂肌表面肌电信号及腰部背伸肌力。多裂肌表面肌电信号用表面肌电测定仪记录,背部肌力采用背力计测定。结果:所有患者脊神经阻滞后腰背疼痛VAS评分、多裂肌平均肌电(averageEMG,AEMG)均低于阻滞前(阻滞前VAS评分为6.85±1.55,肌电值为69.25±2.13)。腰脊神经后内侧支单支、双支、3支、4支阻滞后腰背部的VAS评分分别为5.80±1.05、3.65±1.20、2.80±1.10、2.75±1.15,肌电值分别为62.15±1.85、51.25±1.28、47.30±1.85、45.96±1.98。腰背伸肌力:腰脊神经后内侧支阻滞前和单支、双支、3支、4支阻滞后分别为60、55、48、44、43kg。VAS评分:3支阻滞后<双支阻滞后<单支阻滞后;腰背伸力:3支阻滞后<双支阻滞后<单支阻滞后。4支阻滞后的VAS评分、腰背伸力与3支阻滞后差异无统计学意义。同位脊神经后内侧支及上位双支阻滞VAS评分及背伸力下降幅度明显大于同位及下位双支阻滞。结论:脊神经后内侧支去神经化治疗腰椎关节突关节源性腰痛是有效的,单支、双支去神经化治疗是相对安全的;双支阻滞首选同位脊神经后内侧支及上位双支阻滞,其疗效明显。3支、4支去神经化治疗有一定风险,应谨慎使用。     

Determinants of the intention for using a lumbar support among home care workers with recurrent low back pain

In most effectiveness studies on lumbar supports for patients with low back pain, insufficient data are reported about adherence. In a secondary preventive RCT, we found beneficial effects and a good adherence among home care workers with low back pain. To target the use of lumbar supports on those patients who can benefit optimally from usage, we need to know why people are adherent. We used the attitude, social support and self-efficacy model to identify determinants for prolonged adherence to wearing a lumbar support. The strongest predictor for intending sustained use of a lumbar support was a positive attitude towards lumbar supports, explaining 41% of the variance (B = 1.31; p < 0.001). Social support and self-efficacy played a minor role. The intention for prolonged use of a lumbar support for workers with recurrent back pain was mainly explained by a positive attitude. The discomfort of a lumbar support was outweighed by perceived benefit.     

EMG activity of trunk muscles and torque output during isometric axial rotation exertion: a comparison between back pain patients and matched controls.

Abnormal patterns of trunk muscle activity could affect the biomechanics of spinal movements and result in back pain. The present study aimed to examine electromyographic (EMG) activity of abdominal and back muscles as well as triaxial torque output during isometric axial rotation at different exertion levels in back pain patients and matched controls. Twelve back pain patients and 12 matched controls performed isometric right and left axial rotation at 100%, 70%, 50% and 30% maximum voluntary contractions in a standing position. Surface EMG activity of rectus abdominis, external oblique, internal oblique, latissimus dorsi, iliocostalis lumborum and multifidus were recorded bilaterally. The primary torque in the transverse plane and the coupling torques in sagittal and coronal planes were measured. Results showed that there was a trend (P = 0.08) of higher flexion coupling torque during left axial rotation exertion in back pain patients. Higher activity for external oblique and lower activity for multifidus was shown during left axial rotation exertion in back pain group when compared to the control group. In right axial rotation, back pain patients exhibited lesser activity of rectus abdominis at higher levels of exertion when compared with matched controls. These findings demonstrated that decreased activation of one muscle may be compensated by overactivity in other muscles. The reduced levels of activity of the multifidus muscle during axial rotation exertion in back pain patients may indicate that spinal stability could be compromised. Future studies should consider these alternations in recruitment patterns in terms of spinal stability and internal loading. The findings also indicate the importance of training for coordination besides the strengthening of trunk muscles during rehabilitation process.     

42例腰椎融合术后难治性下腰痛的治疗体会

目的探讨腰椎融合术后骶髂关节病变的特点及治疗方法与疗效。方法回顾性分析42例因腰椎退变性滑脱、腰椎椎间盘突出、腰椎椎管狭窄曾行后路减压、后外侧或椎体间植骨融合及椎弓根内固定术,术后随访12～72个月(平均42.6个月)出现新的难治性持续性下腰痛症状的病例。本研究运用骶髂关节内封闭进行诊断性治疗。阳性标准:疼痛缓解≥75%,采用疼痛视觉模拟量表(visual analogue scale,VAS)进行定量分析。结果阳性12例(28.57%),是否融合L5/S1、术后疼痛缓解期是否≥3个月与诊断阳性率相关,有统计学意义(P<0.05)。结论腰椎融合术后下腰痛部分可能是由骶髂关节病变引起的,L5/S1融合可能促进骶髂关节发生退变。症状以下腰痛症状为主者,手术应慎重。     

微创单侧椎弓根螺钉固定、椎体间融合治疗腰椎疾患所致腰痛的临床观察

目的:评价微创单侧椎弓根螺钉固定、椎间融合治疗腰椎疾患所致腰痛的临床疗效。方法:2003年12月～2006年8月,共收治不同原因所致腰痛患者29例,其中腰椎间盘突出症13例,腰椎不稳8例,椎间盘源性腰痛5例,MED术后复发3例,均采用可扩张管道系统经椎间孔行椎体间植骨融合、单侧椎弓根螺钉固定术治疗。应用视觉模拟评分系统(VAS)评估患者术前、术后疼痛情况,应用Kim方法评价临床效果,应用Schulte方法观察植骨融合情况。结果:1例患者术后出现对侧下肢放射性疼痛,保守治疗无效,再次手术行神经根管减压和内固定后症状缓解。随访21～36个月,平均31.5个月,术前VAS评分为7.7±0.6分,术后3个月时为1.9±0.9分,两者比较有显著性差异(P0.001),术后3个月时Kim优良率为89.7%,末次随访时Kim优良率为96.6%,满意率为96.6%。末次随访时椎间融合率为93.1%,1例可能融合和1例假关节形成。结论:微创单侧椎弓根螺钉固定是治疗腰痛的一种有效方法,但需要严格把握手术适应证。     

椎间盘造影术与椎间盘阻滞术在椎间盘源性腰痛中诊断结果的对比分析

目的比较分析椎间盘造影术与椎间盘阻滞术在椎间盘源性腰痛临床诊断中的检查结果。方法 2008年9～2011年9月收治78例慢性下腰痛患者,男32例,女46例,平均年龄38岁(29岁～46岁),临床表现及影像学检查考虑椎间盘源性腰痛。为进一步诊断进行椎间盘造影术,注射造影剂复制出平时典型腰痛者为阳性,造影诱发痛结果为单节段阳性者同时进行该节段椎间盘阻滞术,造影诱发痛结果为阴性者,选择临床高度怀疑的责任节段进行椎间盘阻滞术。椎间盘内阻滞后30 min,患者腰痛视觉模拟量表(visual analog scale,VAS)评分缓解60%以上者为阳性。记录并分析2种诊断方法的检查结果。结果椎间盘造影术:阳性60例,其中42例为单节段,18例为多节段;阴性18例。椎间盘阻滞术:42例单节段诱发痛阳性病例中30例椎间盘阻滞术阳性;18例诱发痛阴性病例中10例椎间盘阻滞术阳性。结论椎间盘阻滞术的检查结果与椎间盘造影术检查有差异,对椎间盘源性腰痛的诊断方法需要进一步的临床研究。     

The relationships between low back pain and lumbar lordosis: a systematic review and meta-analysis

Background Context

Clinicians regard lumbar lordotic curvature (LLC) with respect to low back pain (LBP) in a contradictory fashion. The time-honored point of view is that LLC itself, or its increment, causes LBP. On the other hand, recently, the biomechanical role of LLC has been emphasized, and loss of lordosis is considered a possible cause of LBP. The relationship between LLC and LBP has immense clinical significance, because it serves as the basis of therapeutic exercises for treating and preventing LBP.

The lumbar spine and low back pain in golf: a literature review of swing biomechanics and injury prevention

BACKGROUND CONTEXT: The golf swing imparts significant stress on the lumbar spine. Not surprisingly, low back pain (LBP) is one of the most common musculoskeletal complaints among golfers. PURPOSE: This article provides a review of lumbar spine forces during the golf swing and other research available on swing biomechanics and muscle activity during trunk rotation. STUDY DESIGN: The role of "modern" and "classic" swing styles in golf-associated LBP, as well as LBP causation theories, treatment, and prevention strategies, are reviewed. METHODS: A PubMed literature search was performed using various permutations of the following keywords: lumbar, spine, low, back, therapy, pain, prevention, injuries, golf, swing, trunk, rotation, and biomechanics. Articles were screened and selected for relevance to injuries in golf, swing mechanics, and biomechanics of the trunk and lumbar spine. Articles addressing treatment of LBP with discussions on trunk rotation or golf were also selected. Primary references were included from the initial selection of articles where appropriate. General web searches were performed to identify articles for background information on the sport of golf and postsurgical return to play. RESULTS: Prospective, randomized studies have shown that focus on the transversus abdominus (TA) and multifidi (MF) muscles is a necessary part of physical therapy for LBP. Some studies also suggest that the coaching of a "classic" golf swing and increasing trunk flexibility may provide additional benefit. CONCLUSIONS: There is a notable lack of studies separating the effects of swing modification from physical rehabilitation, and controlled trials are necessary to identify the true effectiveness of specific swing modifications for reducing LBP in golf. Although the establishment of a commonly used regimen to address all golf-associated LBP would be ideal, it may be more practical to apply basic principles mentioned in this article to the tailoring of a unique regimen for the patient. Guidelines for returning to golf after spine surgery are also discussed.     

Quantitative analysis of the effect of lumbar orthosis on trunk muscle strength and muscle activity in normal subjects

 We studied the effect of lumbar orthosis on trunk muscle strength and muscle activity during flexion-extension bending of the trunk in 31 male volunteers. Trunk muscle strength was measured with a kinetic measurement system. Peak torque was calculated by using the mean torque of five repetitions. Trunk muscle activity was measured with commercially available equipment that has portable EMG data-collection units. The maximum level of the EMG signal was evaluated by employing the analyzing part of the computer's measuring program. With the application of the lumbar orthosis, the strength of the abdominal muscle and the back muscle increased; conversely, the activities of both muscles were decreased significantly. This might imply that lumbar orthosis reduces the load of the trunk muscles during performance. Received: October 5, 2001 / Accepted: February 12, 2002     

脊柱内窥镜下腰脊神经背内侧支射频消融术治疗慢性腰椎小关节源性腰痛

目的探讨脊柱内窥镜下腰脊神经背内侧支射频消融术治疗中老年慢性腰椎小关节源性腰痛的近期疗效。方法采用回顾性队列研究的方法,选取2015年9月—2017年9月杭州市中医院收治的28例慢性腰椎小关节源性腰痛患者,其中14例采用脊柱内窥镜下腰脊神经背内侧支射频消融术治疗(手术组),14例采用经皮腰椎关节突关节封闭治疗(非手术组)。分别对2组患者进行电话、门诊随访,记录治疗前及治疗后1周、1个月、3个月、6个月、1年的腰痛视觉模拟量表(VAS)评分、日本骨科学会(JOA)评分和Oswestry功能障碍指数(ODI)并进行比较,评估2种治疗方案近期疗效的差异。结果治疗前2组患者VAS评分、JOA评分和ODI差异均无统计学意义(P 0.05)。治疗后2组患者各时间点VAS评分、JOA评分和ODI均较治疗前改善,其中手术组与治疗前相比差异有统计学意义(P 0.05);手术组患者VAS评分、JOA评分和ODI的改善情况均优于非手术组,差异有统计学意义(P 0.05)。结论脊柱内窥镜下腰脊神经背内侧支射频消融术治疗慢性腰椎小关节源性腰痛能够显著缓解患者症状、改善预后,近期疗效较好,相比经皮腰椎关节突关节封闭具有一定优势。     

Costs and effects in lumbar spinal fusion. A follow-up study in 136 consecutive patients with chronic low back pain

Although cost-effectiveness is becoming the foremost evaluative criterion within health service management of spine surgery, scientific knowledge about cost-patterns and cost-effectiveness is limited. The aims of this study were (1) to establish an activity-based method for costing at the patient-level, (2) to investigate the correlation between costs and effects, (3) to investigate the influence of selected patient characteristics on cost-effectiveness and, (4) to investigate the incremental cost-effectiveness ratio of (a) posterior instrumentation and (b) intervertebral anterior support in lumbar spinal fusion. We hypothesized a positive correlation between costs and effects, that determinants of effects would also determine cost-effectiveness, and that posterolateral instrumentation and anterior intervertebral support are cost-effective adjuncts in posterolateral lumbar fusion. A cohort of 136 consecutive patients with chronic low back pain, who were surgically treated from January 2001 through January 2003, was followed until 2 years postoperatively. Operations took place at University Hospital of Aarhus and all patients had either (1) non-instrumented posterolateral lumbar spinal fusion, (2) instrumented posterolateral lumbar spinal fusion, or (3) instrumented posterolateral lumbar spinal fusion + anterior intervertebral support. Analysis of costs was performed at the patient-level, from an administrator's perspective, by means of Activity-Based-Costing. Clinical effects were measured by means of the Dallas Pain Questionnaire and the Low Back Pain Rating Scale at baseline and 2 years postoperatively. Regression models were used to reveal determinants for costs and effects. Costs and effects were analyzed as a net-benefit measure to reveal determinants for cost-effectiveness, and finally, adjusted analysis (for non-random allocation of patients) was performed in order to reveal the incremental cost-effectiveness ratios of (a) posterior instrumentation and (b) anterior support. The costs of non-instrumented posterolateral spinal fusion were estimated at DKK 88,285(95% CI 81,369;95,546), instrumented posterolateral spinal fusion at DKK 94,396(95% CI 89,865;99,574) and instrumented posterolateral lumbar spinal fusion + anterior intervertebral support at DKK 120,759(95% CI 111,981;133,738). The net-benefit of the regimens was significantly affected by smoking and functional disability in psychosocial life areas. Multi-level fusion and surgical technique significantly affected the net-benefit as well. Surprisingly, no correlation was found between treatment costs and treatment effects. Incremental analysis suggested that the probability of posterior instrumentation being cost-effective was limited, whereas the probability of anterior intervertebral support being cost-effective escalates as willingness-to-pay per effect unit increases. This study reveals useful and hitherto unknown information both about cost-patterns at the patient-level and determinants of cost-effectiveness. The overall conclusion of the present investigation is a recommendation to focus further on determinants of cost-effectiveness. For example, patient characteristics that are modifiable at a relatively low expense may have greater influence on cost-effectiveness than the surgical technique itself--at least from an administrator's perspective.     

Kinematic and temporal interactions of the lumbar spine and hip during trunk extension in healthy male subjects

Kinematic properties of trunk extension are considered sensitive differentiators of movement between asymptomatic and low back pain subjects. The aim of this study was to quantify the continuous interaction of the hip and lumbar spine kinematics and temporal characteristics as a function of direction during the task of trunk bending backwards and returning to the upright position in healthy young subjects. The sagittal hip and lumbar spine kinematics during the extension task were examined in 18 healthy male subjects. Five trials of trunk extension were recorded for each subject and paired t-tests were then used to determine significant differences (P < 0.05) between the mean lumbar and the hip time-normalized kinematic and temporal variables. The data from the full cycle of trunk extension was analyzed with respect to movement initiation, time to reach peak velocity and peak angular displacement during the full cycle of trunk extension. Three distinct phases of movements were identified based on the continuous movement trajectories of velocity and angular displacement in the lumbar spine and hip; that of extension, return and, a terminal overcorrection phase. There were significant differences identified in the respective mean peak angular velocities of the lumbar spine (21.7 +/- 8.6, 37.0 +/- 14.7, 8.3 +/- 5.0 deg/s) when compared with those of hip (14.6 +/- 6.1, 21.7 +/- 8.5, 5.4 +/- 3.5 deg/s) in each of these three phases. The lumbar spine initiated the movement of trunk extension when bending backwards and returning to the upright position significantly early than that of the hip. These results highlight that in normal healthy adults there is the tendency for the lumbar spine to dominate over the hip during the task of backward trunk bending in terms of the amount and velocity of movement. At the end of extension the kinematics of the lumbar spine and hip kinematic are characterized by a terminal overcorrection phase marking the completion of the movement.