Inclusion of L5-S1 in oblique lumbar interbody fusion-techniques and early complications-a single center experience.

BACKGROUND CONTEXT: The oblique prepsoas retroperitoneal approach to the lumbar spine for interbody fusion or oblique lumbar interbody fusion (OLIF) provides safe access to nearly all lumbar levels. A wide interval between the psoas and aorta allows for a safe and straightforward left-sided oblique approach to the discs above L5. Inclusion of L5-S1 in this approach, however, requires modifications in the technique to navigate the complex and variable vascular anatomy distal to the bifurcation of the great vessels. While different oblique approaches to L5-S1 have been described in the literature, to our knowledge, no previous study has provided guidance for the choice of technique. PURPOSE: Our objectives were to evaluate our early experience with the safety of including L5-S1 in OLIF using 3 different approach techniques, as well as to compare early complications between OLIF with and without L5-S1 inclusion. STUDY DESIGN: Retrospective cohort study. PATIENT SAMPLE: Of the 87 patients who underwent lumbar interbody fusion at 167 spinal levels via an OLIF approach, 19 included L5-S1 (group A) and 68 did not (group B). OUTCOME MEASURES: Demographics, levels fused, indications, operative time (ORT), estimated blood loss (EBL), vascular ligation, intraoperative blood transfusion, length of stay (LOS), discharge to rehabilitation facility, and complications (intraoperative, early ≤90 days, and delayed >90 days) were retrospectively assessed and compared between the groups. METHODS: A retrospective chart and imaging review of all consecutive patients who underwent OLIF at a single institution was performed. Indications for OLIF included symptomatic lumbar degenerative stenosis, deformity, and spondylolisthesis. The L5-S1 level, when included, was approached via one of the following 3 techniques: (1) a left-sided intrabifurcation approach; (2) left-sided prepsoas approach; and (3) right-sided prepsoas approach. Vascular anatomic variations at the lumbosacral junction were evaluated using the preoperative magnetic resonance imaging (MRI), and a "facet line" was proposed to assess this relationship. A minimum of 6 months of follow-up data were assessed for approach-related morbidities. RESULTS: Demographics and operative indications were similar between the groups. The mean follow-up was 10.8 (6-36) months. ORT was significantly longer in group A than in group B (322 vs. 256.3 min, respectively; p=.001); however, no difference in ORT between the two groups was found in the subanalyses for 2- and 3-level surgeries. Differences in EBL (260 vs. 207.91 cc, p=.251) and LOS (2.76 vs. 2.48 days, p=.491) did not reach statistical significance. Ligation of the iliolumbar vein, segmental veins, median sacral vessels, or any vascular structure, as needed for adequate exposure, was required in 13 (68.4%) patients from group A and 4 (5.9%) from group B (p<.00001). Two patients suffered minor vascular injuries (1 in each group); however, no major vascular injuries were seen. Complications were not significantly different between groups A and B, or between the three approaches to L5-S1, and trended lower in the latter part of the series as the learning curve progressed. CONCLUSIONS: Inclusion of L5-S1 in OLIF is safe and feasible through three different approaches but likely involves greater operative complexity. In our early experience, inclusion of L5-S1 showed no increase in early complications. This is the first series that reports the use of 3 different oblique approaches to L5-S1. The proposed "facet line" in the preoperative MRI may guide the choice of approach.

Diagnosing Sacroiliac Joint Pain.

The sacroiliac joint (SIJ) is a diarthrodial joint that has been implicated as a pain generator in approximately 10% to 25% of patients with mechanical low back or leg symptoms. Unique anatomic and physiologic characteristics of SIJ make it susceptible to mechanical stress and also create challenges in the diagnosis of SIJ pain. A variety of inciting causes for SIJ pain may exist, ranging from repetitive low-impact activities such as jogging to increased stress after multilevel spine fusion surgery to high-energy trauma such as in motor vehicle accidents. Similarly, wide variability exists in the clinical presentation of SIJ pain from localized pain or tenderness around the SIJ to radiating pain into the groin or even the entire lower extremity. No pathognomonic clinical history, physical examination finding, or imaging study exists that aids clinicians in making a reliable diagnosis. However, imaging combined with clinical provocative tests might help to identify patients for further investigation. Although provocative physical examination tests have not received reliable consensus, if three or more provocative tests are positive, pursuing a diagnostic SIJ injection is considered reasonable. Notable pain relief with intra-articular anesthetic injection under radiographic guidance has been shown to provide reliable evidence in the diagnosis of SIJ pain.

Not All Hip Dysplasias are the Same: Preoperative CT Version Study and the Need for Reverse Bernese Periacetabular Osteotomy.

BACKGROUND: Dysplastic hip may present with acetabular retroversion with or without femoral retroversion. This retroversion, if not accounted for when performing a periacetabular osteotomy (PAO), will lead to anterior hip pain and early osteoarthritis. A reverse PAO involves anteverting the acetabulum while still obtaining lateral coverage. The purpose of this study was to investigate the relationship between rotational malalignment of acetabulum and femur on 2-dimensional computed tomographic (CT) scans of hips that underwent Bernese PAO and its role in the surgical decision making. METHODS: This retrospective, case-control study examined and compared preoperative 2-dimensional CT scans of hips that underwent reverse PAO to the hips that underwent traditional PAO. RESULTS: Twelve hips underwent reverse PAO from 2005 to 2010. Twelve hips were randomly selected from a cohort of 52 hips that underwent traditional PAO during same time period. Hips that underwent reverse PAO showed crossover sign on preoperative radiographs, but not on postoperative radiographs. Crossover sign was negative preoperatively and postoperatively on hips that underwent traditional PAO. The 2 groups were similar in regards to preoperative lateral center-edge angle, acetabular index, and anterior center-edge angle on plain radiographs and showed significant improvement after surgery.On preoperative CT scans both acetabulae and femurs were retroverted in reverse PAO group. Comparison of the 2 groups demonstrated that acetabular version (16.5±4.9 degrees vs. 25.3±5.6 degrees, P=0.001), femoral version (12.8±10.4 degrees vs. 31.9±8 degrees, P<0.001), and McKibbins Instability Index (29.3±11.9 degrees vs. 57.1±9.8 degrees, P<0.001) were significantly lower for the reverse PAO than the traditional PAO group. Anterior Acetabular Sector Angle (determines anterior coverage) was significantly higher in reverse PAO group, 53.1±13.7 degrees versus 39.7±10.4 degrees (P=0.013). CONCLUSIONS: Retroverted acetabulae seem to be associated with reduced femoral version. Given that retroverted acetabulum and retroverted femur have additive effect and increase chances of anterior hip pain, preoperative identification of correct acetabular, and femoral version by CT scan or MRI is necessary to determine which hip need reverse PAO as opposed to traditional PAO. LEVEL OF EVIDENCE: Level III-Therapeutic.

Current Practice in the Management of Slipped Capital Femoral Epiphysis.

BACKGROUND: The most widely used treatment for slipped capital femoral epiphysis (SCFE) is in situ fixation. In an attempt to reduce the chances of impingement, osteoarthritis, and osteonecrosis, surgeons have started adopting newer surgical techniques. The purpose of this study was to determine the current pattern of treating SCFE. METHODS: A questionnaire was sent electronically to all of the members of the Pediatric Orthopaedic Society of North America. The data were analyzed dividing surgeons into academic versus private practice, years of practice, and number of SCFEs treated per year. RESULTS: Of 990 members, 277 (28%) responded to the survey.Type of practice (academic, n=181 vs. private, n=51): For unstable severe SCFE, surgeons in academic practice use the surgical hip dislocation (SHD) approach significantly more frequently (35.7% vs. 14.9%; P=0.02). A radiolucent table is used significantly more frequently in academic practice for both stable (50.6% vs. 29.8%; P=0.01) and unstable (39.6% vs. 15.2%; P=0.002) SCFE. Fully threaded cannulated screws (44.4% vs. 27.1%; P=0.03), open capsular decompression (63.9% vs. 32.4%; P=0.001), contralateral pinning (79% vs. 58.7%; P=0.005), and postoperative magnetic resonance imaging (MRI) (15.5% vs. 3.9%; P=0.03) are significantly more frequent in academic practice.Years of practice (≤15 y, n=124 vs. >15 y, n=140): For severe stable SCFE, surgeons practicing for ≤15 years do acute osteotomies significantly less frequently (1.8% vs. 9%; P=0.004) and perform SHD significantly more frequently (20.2% vs. 8.2%; P=0.004). For unstable moderate SCFE, SHD is utilized significantly more frequently by surgeons ≤15 years in practice (29.8% vs. 16.5%; P=0.04). Bilateral frog-leg lateral views (86.4% vs. 73.7%; P=0.04), preoperative MRI (36.1% vs. 20.6%; P=0.006), open capsular decompression (69.3% vs. 51.7%; P=0.01) are significantly more frequent among surgeons ≤15 years in practice.Number of SCFE treated per year (<10, n=129 vs. ≥10, n=136): For unstable severe SCFE, surgeons treating ≥10/y perform SHD significantly more frequently (38.6% vs. 26.1%; P=0.02) and do in situ fixation with manual reduction significantly less frequently (11.8% vs. 21.8%; P=0.02). Radiolucent table (54.3% vs. 38%; P=0.01), 7.5 mm screw versus 6.5 mm (62% vs. 45.4%; P=0.01), contralateral pinning (78.9% vs. 67.8%; P=0.04), postoperative MRI (17.6% vs. 9.3%; P=0.04), and postoperative computed tomography (14.7% vs. 7%; 0.04) are significantly more frequent among surgeons doing ≥10/y. Elective implant removal is more common among surgeons treating <10/y (16.2% vs. 6.9%; P=0.02). CONCLUSIONS: Treatment of SCFE varies significantly depending on the surgeon's type of practice, years in practice, and numbers treated per year. Surgeons in academic practice, surgeons with ≤15 years in practice, and surgeons treating greater number of SCFEs are more likely to use SHD to acutely reduce the slip.

Transverse process hooks at upper instrumented vertebra provide more gradual motion transition than pedicle screws.

STUDY DESIGN: Biomechanical study in a porcine model. OBJECTIVE: To determine whether transverse process hooks (TPHs) placed at the proximal end of a long posterior spinal fusion construct provide a more gradual transition to normal motion of the adjacent cephalad motion segment compared with an all pedicle screw (APS) construct. SUMMARY OF BACKGROUND DATA: Proximal junctional kyphosis after instrumentation with long posterior spinal constructs has been increasingly associated with incidence of adjacent segment pathologies. Clinical studies have suggested that proximal anchor type may affect the incidence of proximal junctional kyphosis. METHODS: Biomechanical tests were conducted on porcine thoracic spines before and after implantation of a long spinal fusion construct. In all specimens, dual long rods (Co-Cr) were implanted posteriorly using pedicle screws at T7-T15. Upper instrumented vertebra, T6, received either TPHs (n = 7) or pedicle screws (APSs) (n = 6). Each specimen was tested in flexion-extension then lateral bending. Moments were applied, and vertebral displacements were recorded. Range of motion (ROM) and stiffness (K) were determined for each motion segment. Differences between TPH and APS at the transition were determined using t tests. RESULTS: In flexion-extension, ROM at the most proximal instrumented motion segment was 9% of control for APS versus 21% of control for TPH. Difference between APS and TPH at UIV was 0.5° (P < 0.008). Stiffness of TPH at T6-T7 was significantly lower than APS in FE (P < 0.003). For APS, the greatest mean ROM occurred at the first uninstrumented segment, whereas TPH maintained the pattern of monotonic increases in mean ROM from distal to proximal. CONCLUSION: TPHs at the upper instrumented vertebra provided a more gradual transition to normal motion compared with pedicle screws in long posterior spinal fusion constructs. TPH at the upper instrumented vertebra may be postulated to decrease the incidence of postoperative proximal junctional kyphosis compared with APS. LEVEL OF EVIDENCE: N/A.

Hip dysplasia in patients with Hurler syndrome (mucopolysaccharidosis type 1H).

BACKGROUND: Hip dysplasia is common in patients with Hurler syndrome (HS). However, its prevalence and optimal management is not yet clear because of the rarity of the disease and the prior short life span of these patients. Recent advances in the management of these children using allogeneic hematopoietic cell transplant (HCT) has significantly increased their life expectancy, with many surviving into adulthood. This review was conducted to describe the experience of a single center with hip dysplasia in HS after HCT. METHODS: We performed a retrospective review of hip dysplasia in a consecutive series of patients with HS treated with HCT from 1985 to 2008. RESULTS: At 4.5 (± 2.9) years after HCT all 51 children (102 hips) with HS showed acetabular dysplasia and proximal femur valgus deformity. Mean age at HCT was 1.6 ± 0.9 years. Forty hips (39%) underwent hip reconstructive osteotomies at mean age of 6.8 ± 3.1 years. Significant radiographic improvement was noted in all radiographic parameters at 5.4 ± 3.7 years after hip surgery (P<0.001). Acetabular index improved from 33.3 degrees (± 7.9) preoperative to 24.7 degrees (± 8) after surgery, lateral center edge angle improved from -5.3 degrees (± 10.9) to 35.2 degrees (± 17.8), migration index from 50.7% (± 15.7) to 9.6% (± 13.6), and femoral-neck-shaft angle from 150.9 degrees (± 5.8) to 130.8 degrees (± 12.4). Ten of the 40 hips underwent only proximal femoral varus derotation osteotomy and 30 underwent combined proximal femoral varus derotation osteotomy+pelvic osteotomy. CONCLUSIONS: This study reports high prevalence of hip dysplasia (100%) in patients with HS. As significant radiographic improvement was achieved in those patients treated with surgical interventions we recommend annual orthopaedic evaluation of hips in patients with HS after HCT and intervention with reconstructive femoral and pelvic osteotomies for their hip dysplasia.