Do Current Recommendations for Upper Instrumented Vertebra Predict Shoulder Imbalance? An Attempted Validation of Level Selection for Adolescent Idiopathic Scoliosis

Background

Shoulder balance for adolescent idiopathic scoliosis (AIS) patients is associated with patient satisfaction and self-image. However, few validated systems exist for selecting the upper instrumented vertebra (UIV) post-surgical shoulder balance.

Questions/Purposes

The purpose is to examine the existing UIV selection criteria and correlate with post-surgical shoulder balance in AIS patients.

Methods

Patients who underwent spinal fusion at age 10–18 years for AIS over a 6-year period were reviewed. All patients with a minimum of 1-year radiographic follow-up were included. Imbalance was determined to be radiographic shoulder height |RSH| ≥ 15 mm at latest follow-up. Three UIV selection methods were considered: Lenke, Ilharreborde, and Trobisch. A recommended UIV was determined using each method from pre-surgical radiographs. The recommended UIV for each method was compared to the actual UIV instrumented for all three methods; concordance between these levels was defined as “Correct” UIV selection, and discordance was defined as “Incorrect” selection.

Results

One hundred seventy-one patients were included with 2.3 ± 1.1 year follow-up. For all methods, “Correct” UIV selection resulted in more shoulder imbalance than “Incorrect” UIV selection. Overall shoulder imbalance incidence was improved from 31.0% (53/171) to 15.2% (26/171). New shoulder imbalance incidence for patients with previously level shoulders was 8.8%.

Conclusions

We could not identify a set of UIV selection criteria that accurately predicted post-surgical shoulder balance. Further validated measures are needed in this area. The complexity of proximal thoracic curve correction is underscored in a case example, where shoulder imbalance occurred despite “Correct” UIV selection by all methods.

Electronic supplementary material

The online version of this article (doi:10.1007/s11420-015-9451-y) contains supplementary material, which is available to authorized users.     

富血小板血浆联合关节镜松解治疗冻结肩的疗效分析

目的 评估富血小板血浆（platelet-rich plasma,PRP）联合关节镜松解治疗冻结肩的疗效。方法 回顾性分析2019年1月至2022年12月我科收治的40例采用关节镜松解治疗冻结肩的病人,根据术后注射药物的不同,分为PRP组（20例）和曲安奈德组（20例）,记录并比较两组病人术前、术后1个月、术后3个月、术后6个月、术后12个月的疼痛视觉模拟量表（VAS）评分、Constant-Murley肩关节功能评分以及肩关节主动前屈、外展、外旋的活动度。结果 与术前相比,两组病人术后各观察时间点的VAS评分显著降低,Constant-Murley评分显著升高,差异有统计学意义（P＜0.05）。术后6、12个月时,PRP组病人的Constant-Murley评分显著高于曲安奈德组;术后12个月时,PRP组在主动前屈、主动外展、主动外旋活动度方面均要优于曲安奈德组,差异有统计学意义（P＜0.05）。结论 PRP联合关节镜松解能有效缓解冻结肩病人的疼痛,改善肩关节的功能,是一种有效的治疗方案。     

The incidence of humeral bone resorption in uncemented reverse shoulder arthroplasty and the impact on functional outcomes

BackgroundFull-thickness bone resorption around the humeral stem in shoulder arthroplasty is an increasingly recognized phenomenon, but the impact on outcomes remains unclear. This study aims to investigate prevalence of bone resorption in patients with the Zimmer-Biomet Comprehensive reverse shoulder arthroplasty and the impact on the functional outcomes.MethodsA retrospective analysis was carried out on 65 consecutive patients with primary reverse total shoulder arthroplasty using the Comprehensive Shoulder System from 2014 to 2020, with a minimum of 12-month follow-up. The prevalence of humeral bone resorption was graded from 0 to 4, and risk factors for these changes and their impact on functional outcomes were further investigated.ResultsThe majority of patients (75%) were female with an average age of 75 years (53-93), with an overall average follow-up of 26 months (12-60). Bone resorption occurred in 53 patients (82%), and full-thickness bone resorption occurred in only 8 patients (12%). Metaphyseal bone (zones 1 and 7) is mostly at the risk of high-grade resorption. There was no difference in the final Oxford Shoulder Score between patients who had differential resorption grades from 0 to 4 (P = .5742). None of the risk factors from the previous literature including age, sex, indication for surgery, rotator cuff tear and repair, and intramedullary occupation ratio of the implant showed any impact on the rate of resorption.ConclusionFull-thickness humeral bone resorption occurred in approximately 12% of patients when using the Comprehensive reverse shoulder arthroplasty, but it has no impact on the functional outcomes or revision rate in the short-to-medium term.     

Bullseye: preclinical evaluation of a novel structured light-based imaging workflow to inform glenoid implant positioning in total shoulder arthroplasty

BackgroundAccurate glenoid component positioning during total shoulder arthroplasty (TSA) is critical for prosthesis longevity and postoperative function. Glenoid component positioning in many TSA procedures depends on the insertion of a guide pin through the glenoid vault. However, up to 48% of TSA procedures involve guide pin malpositioning. The aim of this study was to evaluate the ability of a novel structured light imaging system to visualize glenoid guide pin position and trajectory in surgically exposed cadaveric shoulders. Computed tomography (CT)-based and magnetic resonance imaging (MRI)-based workflows and subchondral bone–based and glenoid cartilage–based workflows were compared.MethodsPreoperative cone-beam CT (CBCT) and MRI images were acquired for 5 intact cadaveric shoulders. Following deltopectoral surgical exposure, a glenoid vault guide pin was inserted through the glenoid vault of each scapula as in a clinical TSA procedure. A 3D printed optical tracker was placed over the guide pin, and a 3D optical surface image of the glenoid and tracker was acquired using a handheld structured light sensor. A postprocedural CBCT was acquired for each shoulder to verify guide pin position and trajectory. The imaging procedure was repeated after débridement of the glenoid cartilage to expose subchondral bone. The guide pin was segmented from the postprocedural CBCT image (actual guide pin). A virtual model of the tracker was aligned with a co-linear representation of the intraoperative guide pin (predicted guide pin). A series of image registrations aligned the actual and predicted guide pin positions to yield visualization accuracy, defined as the trajectory and offset errors between predicted and actual guide pins.ResultsThe mean guide pin trajectory and offset errors based on the subchondral bone were 2.22 ± 1.27° and 1.27 ± 0.46 mm for the CT-based workflow and 2.27 ± 1.72° and 1.78 ± 0.92 mm for the MRI-based workflow, respectively. Registration of the cartilage surface models visualized in the MRI images reduced accuracy to a trajectory error of 3.89 ± 1.57° (P = .147) and offset error of 2.28 ± 1.33 mm (P = .217).ConclusionThe Bullseye structured light imaging system presented an accurate approach for glenoid guide pin verification and adjustment during TSA using preoperative MRI or CT. Future development for the implementation of the Bullseye system should focus on improving surface segmentations and automation of the computer vision algorithm needed to facilitate clinical translation.     

Reverse total shoulder arthroplasty in wheelchair-dependent patients: a matched cohort study

BackgroundShoulder function in wheelchair-dependent patients is critical for preserving independence and quality of life due to lower extremity impairment. The purpose of this study was to report the revision rate, as well as clinical and radiological outcome in wheelchair-dependent patients treated with reverse total shoulder arthroplasty (RTSA) and to compare them to an ambulating population.MethodsProspectively obtained data of 21 primary RTSAs in 17 wheelchair-dependent patients (5 male, 12 female) with a median age of 72.4 years (range: 49-80) and a minimum follow-up of 2 years were analyzed retrospectively. Revision rate, clinical (Subjective Shoulder Value = SSV, relative Constant-Murley Score = rCS, wheelchair user’s shoulder pain index = WUSPI) and radiological (glenoid loosening, scapular notching, glenoid inclination) outcome, as well as implant-related parameters (baseplate peg length, glenosphere size, bony augmentation), were compared with a 2:1 matching cohort of 42 ambulating patients (10 male, 32 female) with a median age of 72.5 years (range: 56-78).ResultsThe revision rate was 9.5% in both cohorts. In the wheelchair cohort, two shoulders had to be revised due to a complete baseplate dislocation. In the matching cohort, four shoulders had to be revised due to one prosthetic dislocation, one traumatic and one atraumatic scapular spine fracture with glenoid baseplate dislocation, and one fracture of the greater tuberosity. Median preoperative SSV and rCS did not differ significantly between cohorts. Postoperative SSV was also comparable (wheelchair: median 70 (range: 10-99) vs. matching: median 70 (30-100), p = n.s.). Relative CS was significantly lower in the wheelchair cohort (65% vs. 81.4%, P = .004). Median postoperative WUSPI was 35 points (range: 13-40) for difficulty and 0 points for pain (range: 0-29). The highest difficulty and pain were found for ‘hygiene behind the back’ and ‘propulsion of wheelchair up a ramp or on uneven surface’. Glenoid loosening, scapular notching, and postoperative baseplate inclination did not differ significantly between cohorts. In the wheelchair cohort, glenoid autograft augmentation (38.1% vs. 7.1%, P = .002) and implantation of baseplates with longer pegs were performed more often (≥ 25mm: 38.1% vs. 7.1%, P = .004).ConclusionRTSA is a valuable therapeutic option for the treatment of advanced OA or irreparable rotator cuff tears in wheelchair-bound patients with high patient satisfaction. Postoperatively, poorer function and a higher rate of baseplate dislocations might be anticipated compared to ambulating patients.     

Distance traveled to undergo revision shoulder arthroplasty is impacted by patient demographics and exceeds that of primary shoulder arthroplasty

BackgroundPrevious research has highlighted disparities in access to and outcomes following shoulder arthroplasty. The purpose of this study is to compare travel distance for primary vs. revision surgery and to determine the relationships between travel distance to undergo revision shoulder arthroplasty and patient demographics and postoperative adverse outcomes. We hypothesized that older patients, those with increased medical comorbidities, and those with greater financial resources would travel farther for surgery.MethodsThe Healthcare Cost and Utilization Project, American Hospital Association, and UnitedStatesZipCodes.org Enterprise data sets were compiled to collect data on patient demographics, operation performed, and postoperative adverse outcomes. Population-weighted zip code centroid points of patients’ residences as well as hospital coordinates were used to approximate the distance traveled to undergo shoulder arthroplasty. Kruskal-Wallis tests and logistic regression analyses were used to analyze the relationship between travel distance and patients’ demographics and postoperative outcomes.ResultsPatients traveled farther to undergo revision shoulder arthroplasty than to undergo primary shoulder arthroplasty (P = .0001). Among patients who underwent revision operations, older age (P = .0001) and increased medical comorbidities (P = .003) were associated with decreased travel distance. White patients and those with commercial insurance traveled farther to receive care (P = .0001). There were no clinically significant associations between postoperative outcomes following revision surgery and travel distance.ConclusionPatients may travel farther to undergo revision surgery owing to patient preferences or because these complex operations are performed at fewer centers. Younger and healthier patients, white patients, and those with commercial insurance plans traveled farther to receive care. Future work is needed to determine the underlying causes of these disparities and whether it is patient preferences or systemic factors such as hospital density or access to high-quality health insurance that are influencing access to this specialized surgical care.