Anterior Lumbar Interbody Fusion With Cement Augmentation Without Posterior Fixation to Treat Isthmic Spondylolisthesis in an Osteopenic Patient-A Surgical Technique.

BACKGROUND: Anterior lumbar interbody fusion (ALIF) has been well established as an effective surgical intervention for chronic back pain due to osteoporotic vertebral collapse. Historically, ALIF has consisted of an anterior approach to disc height restoration with a subsequent posterior pedicle screw fixation. Although the applications of cement augmentation with posterior fixation have been previously reported, treatment of patients with both isthmic spondylolisthesis and decreased bone mineral density using a stand-alone ALIF is controversial because of concerns for decreased fusion rates and increased subsidence risk, respectively. We report a case of stand-alone ALIF used to treat a low-grade isthmic spondylolisthesis in the setting of idiopathic thoraco-lumbar scoliosis in a patient with secondary degenerative changes and discuss the benefits of this surgical technique in a patient with several comorbidities. METHODS: An osteopenic 66-year-old woman with multiple medical comorbidities and 2 years of left radicular leg pain was found to have a Myerding grade I isthmic spondylolisthesis in the setting of idiopathic thoraco-lumbar scoliosis with secondary changes. The patient underwent an L5-S1 stand-alone ALIF with anterior cement augmentation without posterior pedicle screw fixation. RESULTS: The patient experienced immediate relief of radicular leg pain postoperatively and had an uneventful course. At 2 years follow-up, she remained symptom free, and radiographs showed excellent fusion and maintenance of intervertebral disc height. CONCLUSIONS: The use of stand-alone ALIF with anterior cement augmentation of the vertebral bodies is a surgical technique that could produce excellent improvement in patients with low-grade isthmic spondylolisthesis in the setting of osteopenia. The use of the all-anterior approach in similar patients with multiple medical comorbidities can also be a useful technique, as it decreases associated morbidity of surgery and complication risks associated with prolonged operative times.

Lateralized Center of Rotation and Lower Neck-Shaft Angle Are Associated With Lower Rates of Scapular Notching and Heterotopic Ossification and Improved Pain for Reverse Shoulder Arthroplasty at 1 Year.

Heterotopic ossification and scapular notching are common following reverse total shoulder arthroplasty. Compared with the original Grammont-style prosthesis with a medialized center of rotation (COR) and a 155° neck-shaft angle, lateralization of COR and reduction of neck-shaft angle have been associated with decreased incidence of scapular notching. The authors hypothesized that these design features may also be effective in reducing heterotopic ossification after reverse total shoulder arthroplasty. Ninety-seven consecutive patients who underwent reverse total shoulder arthroplasty performed by a single surgeon were included in the study. Forty-eight patients received a Grammont-style prosthesis, and 49 received a prosthesis with either 6 mm or 10 mm of lateral COR offset and a 135° neck-shaft angle. Radiographs at 1-year follow-up were reviewed by 2 surgeons for notching and heterotopic ossification. Patient-reported outcome scores and range of motion were also compared between the groups. More patients in the Grammont-style group showed scapular notching (Grammont, 35.4%; lateral COR, 12.2%; P=.018) and heterotopic ossification (Grammont, 47.9%; lateral COR, 22.4%; P=.009). The lateralized COR group reported lower pain on the visual analog scale (Grammont mean, 1.1; lateral COR mean, 0.5; P=.01) and trended toward better American Shoulder and Elbow Surgeons scores (Grammont mean, 77.2; lateral COR mean, 83.4; P=.05). However, range of motion was similar between the 2 groups. Compared with the Grammont-style prosthesis, the lateralized COR prosthesis with a decreased neck-shaft angle resulted in a lower incidence of both scapular notching and heterotopic ossification as well as better pain scores and a trend toward improved function at 1 year after reverse total shoulder arthroplasty. [Orthopedics. 2018; 41(4):230-236.].

Computed tomography underestimates rotator cuff pathology in patients with glenohumeral osteoarthritis.

BACKGROUND: Computed tomography (CT) is the standard assessment of glenoid morphology before shoulder arthroplasty and is commonly used to evaluate rotator cuff pathology in patients with glenohumeral osteoarthritis (GHOA). Magnetic resonance imaging (MRI) is not routinely used in this setting but has higher sensitivity in diagnosing full-thickness rotator cuff tears (RCT) and is considered the gold standard. The purpose of this study was to determine the sensitivity and specificity of CT in diagnosing full-thickness RCTs and compare the evaluation of fatty infiltration and muscle atrophy on CT vs. MRI in the setting of GHOA. METHODS: In this retrospective case-controlled study, we identified 49 patients from a prospectively maintained 2-surgeon registry who received preoperative CT and MRI scans for the evaluation of GHOA between 2011 and 2016. Three fellowship-trained shoulder surgeons assessed rotator cuff integrity, fatty infiltration, and muscle atrophy in the CT and MRI scans. RESULTS: CT sensitivity and specificity were 20% and 95.5%, respectively. Fatty infiltration was significantly lower on CT for the supraspinatus (P = .003), infraspinatus (P < .001), and subscapularis (P = .0182), whereas muscle atrophy was significantly lower on CT for only the supraspinatus (P = .0023). CONCLUSIONS: Our results suggest that CT underestimates the frequency of full-thickness RCTs and the severity of fatty infiltration and muscle atrophy in the setting of GHOA before total shoulder arthroplasty.

Critical shoulder angle is associated with full-thickness rotator cuff tears in patients with glenohumeral osteoarthritis.

BACKGROUND: Higher critical shoulder angle (CSA) is correlated with rotator cuff tears (RCTs), whereas lower CSA is associated with glenohumeral osteoarthritis (OA). Our goal was to investigate whether patients with concurrent glenohumeral OA and full-thickness RCTs demonstrate a higher CSA than patients with OA alone. METHODS: Using a 2-surgeon shoulder arthroplasty registry, we identified 31 patients with glenohumeral OA and full-thickness RCTs confirmed by plain radiography and magnetic resonance imaging, respectively. Sixty-two age- and gender-matched controls (1:2 ratio) with glenohumeral OA and an intact rotator cuff were identified from the same registry. Two independent observers evaluated the radiographs for CSA and acromiohumeral index. RESULTS: The average CSA was 30° in the OA control group and 35° in the concurrent RCT and OA group (P < .0001). Acromiohumeral index was comparable between the groups (P = .13). Interobserver reliability of the independent reviewers was excellent (κ = 0.89; Ρ = 0.95). The receiver operating characteristic curve for CSA demonstrated that a value >35° was 90% specific and 52% sensitive for a full-thickness RCT in the setting of OA (area under curve = 0.84). CONCLUSION: Concurrent glenohumeral OA and full-thickness RCT are associated with greater CSA values compared with patients with glenohumeral OA alone. The CSA measurement may be useful in determining the need for magnetic resonance imaging to assess rotator cuff integrity in the arthritic population.

Biomechanical analysis of an expandable lateral cage and a static transforaminal lumbar interbody fusion cage with posterior instrumentation in an in vitro spondylolisthesis model.

OBJECTIVE: Insufficient biomechanical data exist from comparisons of the stability of expandable lateral cages with that of static transforaminal lumbar interbody fusion (TLIF) cages. The purpose of this biomechanical study was to compare the relative rigidity of L4-5 expandable lateral interbody constructs with or without additive pedicle screw fixation with that of L4-5 static TLIF cages in a novel cadaveric spondylolisthesis model. METHODS: Eight human cadaver spines were used in this study. A spondylolisthesis model was created at the L4-5 level by creating 2 injuries. First, in each cadaver, a nucleotomy from 2 channels through the anterior side was created. Second, the cartilage of the facet joint was burred down to create a gap of 4 mm. Light-emitting-diode tracking markers were placed at L-3, L-4, L-5, and S-1. Specimens were tested in the following scenarios: intact model, bilateral pedicle screws, expandable lateral 18-mm-wide cage (alone, with unilateral pedicle screws [UPSs], and with bilateral pedicle screws [BPSs]), expandable lateral 22-mm-wide cage (alone, with UPSs, and with BPSs), and TLIF (alone, with UPSs, and with BPSs). Four of the spines were tested with the expandable lateral cages (18-mm cage followed by the 22-mm cage), and 4 of the spines were tested with the TLIF construct. All these constructs were tested in flexion-extension, axial rotation, and lateral bending. RESULTS: The TLIF-alone construct was significantly less stable than the 18- and 22-mm-wide lateral lumbar interbody fusion (LLIF) constructs and the TLIF constructs with either UPSs or BPSs. The LLIF constructs alone were significantly less stable than the TLIF construct with BPSs. However, there was no significant difference between the 18-mm LLIF construct with UPSs and the TLIF construct with BPSs in any of the loading modes. CONCLUSIONS: Expandable lateral cages with UPSs provide stability equivalent to that of a TLIF construct with BPSs in a degenerative spondylolisthesis model.