Tapping insertional torque allows prediction for better pedicle screw fixation and optimal screw size selection

Background contextThere is currently no reliable technique for intraoperative assessment of pedicle screw fixation strength and optimal screw size. Several studies have evaluated pedicle screw insertional torque (IT) and its direct correlation with pullout strength. However, there is limited clinical application with pedicle screw IT as it must be measured during screw placement and rarely causes the spine surgeon to change screw size. To date, no study has evaluated tapping IT, which precedes screw insertion, and its ability to predict pedicle screw pullout strength.PurposeThe objective of this study was to investigate tapping IT and its ability to predict pedicle screw pullout strength and optimal screw size.Study designIn vitro human cadaveric biomechanical analysis.MethodsTwenty fresh-frozen human cadaveric thoracic vertebral levels were prepared and dual-energy radiographic absorptiometry scanned for bone mineral density (BMD). All specimens were osteoporotic with a mean BMD of 0.60±0.07 g/cm². Five specimens (n=10) were used to perform a pilot study, as there were no previously established values for optimal tapping IT. Each pedicle during the pilot study was measured using a digital caliper as well as computed tomography measurements, and the optimal screw size was determined to be equal to or the first size smaller than the pedicle diameter. The optimal tap size was then selected as the tap diameter 1 mm smaller than the optimal screw size. During optimal tap size insertion, all peak tapping IT values were found to be between 2 in-lbs and 3 in-lbs. Therefore, the threshold tapping IT value for optimal pedicle screw and tap size was determined to be 2.5 in-lbs, and a comparison tapping IT value of 1.5 in-lbs was selected. Next, 15 test specimens (n=30) were measured with digital calipers, probed, tapped, and instrumented using a paired comparison between the two threshold tapping IT values (Group 1: 1.5 in-lbs; Group 2: 2.5 in-lbs), randomly assigned to the left or right pedicle on each specimen. Each pedicle was incrementally tapped to increasing size (3.75, 4.00, 4.50, and 5.50 mm) until the threshold value was reached based on the assigned group. Pedicle screw size was determined by adding 1 mm to the tap size that crossed the threshold torque value. Torque measurements were recorded with each revolution during tap and pedicle screw insertion. Each specimen was then individually potted and pedicle screws pulled out “in-line” with the screw axis at a rate of 0.25 mm/sec. Peak pullout strength (POS) was measured in Newtons (N).ResultsThe peak tapping IT was significantly increased (50%) in Group 2 (3.23±0.65 in-lbs) compared with Group 1 (2.15±0.56 in-lbs) (p=.0005). The peak screw IT was also significantly increased (19%) in Group 2 (8.99±2.27 in-lbs) compared with Group 1 (7.52±2.96 in-lbs) (p=.02). The pedicle screw pullout strength was also significantly increased (23%) in Group 2 (877.9±235.2 N) compared with Group 1 (712.3±223.1 N) (p=.017). The mean pedicle screw diameter was significantly increased in Group 2 (5.70±1.05 mm) compared with Group 1 (5.00±0.80 mm) (p=.0002). There was also an increased rate of optimal pedicle screw size selection in Group 2 with 9 of 15 (60%) pedicle screws compared with Group 1 with 4 of 15 (26.7%) pedicle screws within 1 mm of the measured pedicle width. There was a moderate correlation for tapping IT with both screw IT (r=0.54; p=.002) and pedicle screw POS (r=0.55; p=.002).ConclusionsOur findings suggest that tapping IT directly correlates with pedicle screw IT, pedicle screw pullout strength, and optimal pedicle screw size. Therefore, tapping IT may be used during thoracic pedicle screw instrumentation as an adjunct to preoperative imaging and clinical experience to maximize fixation strength and optimize pedicle “fit and fill” with the largest screw possible. However, further prospective, in vivo studies are necessary to evaluate the intraoperative use of tapping IT to predict screw loosening/complications.     

Vertebral bone quality score predicts fragility fractures independently of bone mineral density

BackgroundCurrent evidence suggests that dual-energy x-ray absorptiometry (DXA) scans, the conventional method defining osteoporosis, is underutilized and, when used, may underestimate patient risk for skeletal fragility. It has recently been suggested that other imaging modalities may better estimate bone quality, such as the magnetic resonance imaging (MRI)-based vertebral bone quality (VBQ) score which also may assess vertebral compression fracture risk in patients with spine metastases.PurposeTo evaluate whether VBQ score is predictive of fragility fractures in a population with pre-existing low bone density and at high-risk for fracture.Study Design/SettingRetrospective single-center cohort.Patient SamplePatients followed at a metabolic bone clinic for osteopenia and/or osteoporosis.Outcome MeasuresRadiographically-documented new-onset fragility fracture.MethodsPatients with a DXA and MRI scans at the time of consultation and ≥2-year follow-up were included. Details were gathered about patient demographics, health history, current medication use, and serological studies of kidney function and bone turnover. For each patient, VBQ score was calculated using T1-weighted lumbar MRI images. Univariable and multivariable analyses were used to identify the independent predictors of a new fragility fracture. To support the construct validity of VBQ, patient VBQ scores were compared to those in a cohort of 45 healthy adults.ResultsSeventy-two (39.1%) study participants suffered fragility fractures, the occurrence of which was associated with higher VBQ score (3.50 vs. 3.01; p<.001), chronic glucocorticoid use (30.6% vs. 15.2%; p=.014), and a history of prior fragility fracture (36.1% vs. 21.4%; p=.030). Mean VBQ score across all patients in the study cohort was significantly higher than the mean VBQ score in the healthy controls (p<.001). In multivariable analysis, new-onset fracture was independently associated with history of prior fracture (OR=6.94; 95% confidence interval [2.48–19.40]; p<.001), higher VBQ score (OR=2.40 per point; [1.30–4.44]; p=.003), higher body mass index (OR=1.09 per kg/m²; [1.01–1.17]; p=.03), and chronic glucocorticoid use (OR=2.89; [1.03–8.17]; p=0.043). Notably, DXA bone mineral density (BMD) was not found to be significantly predictive of new-onset fractures in the multivariable analysis (p=.081).ConclusionsHere we demonstrate the novel, MRI-derived VBQ score is both an independent predictor of fragility fracture in at-risk patients and a superior predictor of fracture risk than DXA-measured BMD. Given the frequency with which MRIs are obtained by patients undergoing spine surgery consultation, we believe the VBQ score could be a valuable tool for estimating bone quality in order to optimize the management of these patients.     

Longitudinal associations between cancer history and cognitive functioning among older adults

ObjectivesThis study aimed to examine (1) whether cancer history accelerates older adults’ rates of cognitive decline over time and (2) whether chemotherapy increases older cancer patients’/ survivors’ rates of cognitive decline over time.MethodsThis longitudinal study drew a subsample of 8811 adults aged 65 or older from Wave 6 of the Health and Retirement Study in 2002 and followed biennually until Wave 13 in 2016. Linear mixed-effects models were performed to test whether cancer history and chemotherapy were associated with accelerated rates of cognitive decline over time among older adults in different age groups.ResultsMiddle-old adults (aged 75–84) with a cancer history had significantly reduced rates of cognitive decline over time, including the global measure of cognitive functioning (B = 0.16, p< .01), mental status (B = 0.08, p< .01), and episodic memory (B = 0.09, p< .05) compared to their counterparts without a cancer history. This effect was not significant for the youngest-old (aged 65–74) or oldest-old adults (aged 85 or older). Also, chemotherapy was not significantly associated with older cancer patients’/survivors’ cognitive functioning at baseline or over time in different age groups.ConclusionsThis study finds that cancer history and chemotherapy do not further exacerbate older adults’ cognitive functioning over time. On the contrary, cancer history shows a “protective” effect on middle-old adults’ cognitive functioning. This encouraging finding indicates that older adults can be more actively engaged in the decision-making of treatments and following care plans. Future mediation studies are needed to further investigate underlying mechanisms.     

Cerebrovascular bypass for ruptured aneurysms: A case series

In patients with aneurysmal subarachnoid hemorrhage (aSAH) unfavorable for endovascular or traditional open surgical techniques, surgical revascularization strategies comprise one of remaining limited options. There is nonetheless a paucity of data on the safety and efficacy of bypass in aSAH. In this study, we aimed to investigate complications and outcomes in a cohort of patients with aSAH treated with bypass. A prospective single-surgeon database of consecutive patients treated for aSAH between 2013 and 2018 was retrospectively analyzed. Complications and functional status at discharge were recorded and analyzed for the patients that underwent bypass surgery. Forty patients with aSAH were treated with bypass surgery (23 extracranial-intracranial; 17 intracranial-intracranial). All-cause perioperative mortality was 13% (6 patients). At discharge and at mean 14-month follow up, respectively, 16/40 (40%) and 16/25 (64%) of patients achieved a Glasgow Outcome Score of 4–5. All-cause, in-hospital complications occurred in 28 patients (70%), of which any ischemic complication occurred in 20 patients (50%), 7 (18%) being open surgical complications. This work represents the largest modern series of bypass for aSAH to date. In cases of aSAH unfavorable for endovascular intervention or traditional open surgical techniques, bypass remains a viable option in this complex group of patients.     

Quantitative Romberg using a force plate: an objective measure for cervical myelopathy

BACKGROUND CONTEXTSurgical decision making for cervical spondylotic myelopathy (CSM) relies on evaluation of symptoms and physical examination. The Romberg test is a clinical exam used to identify balance issues with CSM. However, the Romberg test has a subjective interpretation and has a binary (positive or negative) result.PURPOSEThis study aims to compare force plate pressure readings during a standard Romberg test in patients with CSM to age-matched normal healthy volunteers.STUDY DESIGN/SETTINGProspective cross sectional observational comparative cohort from a single multi-surgeon spine center.PATIENT SAMPLEPatients who were clinically diagnosed with CSM were compared to age-matched healthy volunteers without a clinical history of spine pathology.OUTCOME MEASURESQuantitative Romberg Force Plate MeasurementsMETHODSPatients with CSM requiring surgery and healthy normal volunteers were asked to perform the Romberg test while on a force plate measuring the center of pressure (COP): standing up straight with arms extended for 30 seconds with eyes open, followed by 30 seconds with eyes closed. The change for total sway area, sway frequency and sway speed with eyes closed and eyes open were calculated and compared between patients with CSM and healthy volunteers.RESULTSThirty-four CSM patients were age-matched to 34 healthy volunteers. There was a larger change in quantitative Romberg measurements with eyes open versus eyes closed in CSM patients compared to normal volunteers for maximum lateral movement (10.79 cm vs. 0.94 cm, p=.003), maximum anterior-posterior movement (15.06 cm vs. 10.00 cm p=.201), total lateral CoP movement (89.82cm vs. 18.71cm, p=.007), total AP CoP movement (154.68 cm vs. 87.47 cm, p=.601), total CoP trace movement (199.79 cm vs. 88.44 cm, p=.014), sway area (284.74 cm² vs. 57.76 cm², p=.006), and average speed (7.00 cm/s vs. 2.91 cm/s, p=.006).DISCUSSIONPoor standing balance can be quantified in patients with CSM. Quantifying standing balance in patients with CSM shows significantly worse objective measures than age-matched healthy volunteers. The Romberg test on a force plate may help diagnose and evaluate patients with CSM, guide patient management and potentially grade the severity of spinal pathology. Further studies are needed to determine its utility in monitoring disease progression and measure treatment effectiveness.     

Biceps tenotomy versus soft-tissue tenodesis in females aged 60 years and older with rotator cuff tears

BackgroundRecently, to treat the long head of the biceps tendon lesions in addition to rotator cuff repair has been recommended. However, the differences in clinical outcomes between biceps tenotomy and tenodesis for middle-aged and elderly females remains unclear. The purpose of this study was to compare the outcomes of biceps tenotomy and soft-tissue tenodesis that were performed concurrently with arthroscopic rotator cuff repair in ≥60-year-old females.MethodsFemale shoulders that underwent arthroscopic rotator cuff repair in our institute in 2016 were retrospectively reviewed. This study included 66 shoulders with concurrent biceps tenotomy or soft-tissue tenodesis: tenotomy group, 41 shoulders; soft-tissue tenodesis group, 25 shoulders. Clinical scores, biceps pain (visual analogue scale, VAS), Popeye deformity, and biceps strength (%contralateral side) were compared between the two groups.ResultsThe mean age was significantly higher in the tenotomy group than the soft-tissue tenodesis group (72 ± 4 and 68 ± 6 years, respectively; P = 0.002). There were no significant differences in post-operative JOA and UCLA scores between the groups. VAS for biceps pain was significantly higher at postoperative 6 months in the tenotomy group than the soft-tissue tenodesis group (2.9 ± 2.5 and 1.7 ± 1.6, respectively, P = 0.03), though there were no significant differences at postoperative 3, 12, and ≥24 months. Subjective evaluation of Popeye deformity was not significantly different between the groups. Postoperative biceps strength was significantly lower in the tenotomy group than the soft-tissue tenodesis group (89.9% and 102.8%, respectively, P = 0.02).ConclusionsBoth biceps tenotomy and soft-tissue tenodesis concurrent with rotator cuff repair in ≥60-year-old female patients resulted in good outcomes. Shoulders with soft-tissue tenodesis demonstrated earlier improvement in postoperative biceps pain and better postoperative biceps strength than those with tenotomy. There were no differences in objective and subjective Popeye deformity between tenotomy and soft-tissue tenodesis. The LHB procedures, tenotomy or tenodesis, can be selected depending on surgeons’ preference.     

支撑棒技术在后路胸腰椎矫形融合术治疗伴严重冠状面失衡和骨盆倾斜脊柱侧凸中的临床应用

【摘要】 目的：评价应用支撑棒（kickstand rod,KR）技术的后路胸腰椎矫形融合术治疗伴有严重冠状面失衡（coronal imbalance,CI）和骨盆倾斜（pelvic obliquity,PO）脊柱侧凸患者的矫正效果及其并发症。方法：回顾性分析2019年1月~2020年12月在我院接受后路胸腰椎矫形融合术（脊柱-骨盆融合手术）治疗的45例伴严重CI和PO的脊柱侧凸的患者资料。男性6例,女性39例,年龄51.2±17.5岁（12~73岁）,随访时间16.4±5.3个月（11~26个月）。按骨盆固定的方式将使用经S2骶髂螺钉（S2 alar-iliac,S2AI）而未应用支撑棒技术行骨盆固定的患者纳入非KR组（25例）,将使用支撑棒内固定技术行骨盆固定的患者纳入KR组（20例）。术前、术后7d和末次随访时在全脊柱正侧位X线片测量冠状面平衡距离（coronal balance distance,CBD）、骨盆倾斜角（pelvic obliquity angle,POA）、侧凸Cobb角、腰骶半弯（lumbosacral fractional curve,LFC）和骨盆入射角（pelvic incidence,PI）,比较两组患者脊柱骨盆参数矫正率以及末次随访时的矫正丢失率,记录患者术后及随访期间的并发症发生情况。结果：两组患者术前的侧凸Cobb角、POA、CBD、LFC和PI均无统计学差异（P＞0.05）。两组患者侧凸Cobb角、POA、CBD、LFC术后7d时与术前相比均有明显改善（P＜0.05）,KR组患者末次随访时与术后7d相比无统计学差异（P＞0.05）,非KR组患者在末次随访时POA出现明显矫正丢失（P＜0.05）。KR组和非KR组患者术后POA的矫正率分别为（66.9±13.4）%和（44.2±23.4）%,CBD的矫正率分别为（58.5±20.9）%和（42.9±20.9）%,有统计学差异（P＜0.05）;其余影像学参数在两组患者间均无统计学差异（P＞0.05）。随访期间KR组1例发生断棒,非KR组3例发生术后CI,两组并发症发生率的差异无统计学意义（χ2=0.672,P=0.412）。结论：对于合并严重CI和PO的脊柱侧凸患者,与传统骨盆固定方式相比,应用KR技术的后路矫形脊柱-骨盆融合手术可以在矫正脊柱侧凸的同时维持良好的骨盆水平和冠状面平衡。     

Flexibility does not affect the dorsiflexion of foot and the popliteal angle in young adults

BackgroundThe aim of the study was to assess how flexibility affects the dorsiflexion of foot and the popliteal angle test results in junior high school students.MethodsThe subjects were 142 students from the 2nd, and 3rd year of Poznań junior high schools (age between 13 and 15).Each subject was examined 6 times: there were 3 raters, a specialist in orthopaedics, a resident doctor and a physical therapy student, and each of them performed 2 measurements. Flexibility was also measured using the Beighton scale (score from 0 to 9).ResultsSince the Beighton scale is ordinal in order to evaluate the relationship between flexibility and the range of motion Spearman's rank correlation coefficient was calculated. The statistical analysis showed no correlation between flexibility measured on the Beighton scale and the range of passive foot dorsiflexion and the popliteal angle.ConclusionsThe degree of flexibility does not affect the dorsiflexion of the foot and the popliteal angle in junior high students. At this age the range of dorsiflexion is determined by the length of the triceps surae muscle while the popliteal angle depends on the length of the muscles on the back of the thigh.