Rolando F. Roberto

The natural history of cardiac and pulmonary function decline in patients with duchenne muscular dystrophy

Study Design. Retrospective review of scoliosis progression, pulmonary and cardiac function in a series of patients with Duchenne Muscular Dystrophy (DMD). Objective. To determine whether operative treatment of scoliosis decreases the rate of pulmonary function loss in patients with DMD. Summary of Background Data. It is generally accepted that surgical intervention should be undertaken in DMD scoliosis once curve sizes reach 35° to allow intervention before critical respiratory decline has occurred. There are conflicting reports, however, regarding the effect of scoliosis stabilization on the rate of pulmonary function decline when compared to nonoperative cohorts. Methods. We reviewed spinal radiographs, echocardiograms, and spirometry, hospital, and operative records of all patients seen at our tertiary referral center from July 1, 1992 to June 1, 2007. Data were recorded to Microsoft Excel (Microsoft, Redmond, WA) and analyzed with SAS (SAS Institute, Cary, NC) and R statistical processing software (www.r-project.org). Results. The percent predicted forced vital capacity (PPFVC) decreased 5% per year before operation. The mean PPFVC was 54% (SD = 21%) before operation with a mean postoperative PPFVC of 43% (SD = 14%). Surgical treatment was associated with a 12% decline in PPFVC independent of other treatment variables. PPFVC after operation declined at a rate of 1% per year and while this rate was lower, it was not significantly different than the rate of decline present before operation (P = 0.18). Cardiac function as measured by left ventricular fractional shortening declined at a rate of 1% per year with most individuals exhibiting a left ventricular fractional shortening rate of more than 30 before operation. Conclusion. Operative treatment of scoliosis in DMD using the Luque Galveston method was associated with a reduction of forced vital capacity related to operation. The rate of pulmonary function decline after operation was not significantly reduced when compared with the rate of preoperative forced vital capacity decline.

The utility and accuracy of computed tomography in the diagnosis of occipitocervical dissociation

BACKGROUND CONTEXT Atlantooccipital dislocation (AOD) results in profound patient morbidity and mortality and is difficult to accurately diagnose using current evaluation techniques. PURPOSE To evaluate the utility of computed tomography (CT) images in the diagnosis of AOD and compare the revised occipital condyle-C1 interval (CCI) and the condylar sum to the current radiographic criteria used to detect AOD. STUDY DESIGN Retrospective review to evaluate the sensitivity, specificity, and the interobserver reliability of eight radiographic criteria as applied to CT imaging. PATIENT SAMPLE Ten cases of clinical AOD and 10 cases of non-AOD cervical injury. OUTCOME MEASURES Measured values: revised CCI, Wholey basion-dens interval (BDI), and Harris basion-axis interval (BAI). Calculated values: Sun interspinous ratio, Powers ratio, and condylar sum. Assessment of Lee X-line and atlantooccipital joint asymmetry. METHODS A board certified neuroradiologist, two orthopedic spine surgeons, and two medical students reviewed the CT images for each patient in the series and applied the aforementioned criteria. RESULTS Average sensitivity between all reviewers for CCI, condylar sum, and atlantooccipital asymmetry was highest at 1.0, 1.0, and 0.96, respectively. Basion-dens interval, X-line, Sun ratio, BAI, and Powers ratio had sensitivities of 0.72, 0.54, 0.32, 0.26, and 0.26, respectively. Revised CCI and condylar sum had significantly better sensitivity than any other test (vs. BDI, p=.014, all others, p<.001) except atlantooccipital asymmetry (p>.99). Specificity for all measurements was 0.78 or greater, except X-line at 0.38. Interobserver reliabilities were the greatest for CCI, condylar sum, atlantooccipital asymmetry, and BDI. CONCLUSIONS The revised CCI (>2.5 mm abnormal) and condylar sum (≥5 mm abnormal) are highly sensitive and reliable radiographic criteria for the detection of AOD when applied to CT imaging.

Case report: incisional hernia as a complication of extreme lateral interbody fusion

BACKGROUND CONTEXT Minimal access surgery is becoming more popular for spinal fusion because of a lower theoretical risk of complications and shorter postoperative recovery period, compared with the traditional open approach. The lateral approach uses retroperitoneal transpsoas access to the vertebra, obviating the need for an approach surgeon and minimizing muscular disruption, thus allowing a quicker recovery. Initial reports of the lateral transpsoas procedure described few complications. However, a number of complications have subsequently been documented. To our knowledge, there has not been a description of an incisional hernia after this approach. PURPOSE To report the rare complication of an incisional hernia after a minimal access lateral transpsoas approach for lumbar interbody fusion. STUDY DESIGN Case report. METHODS We reviewed the hospital charts, radiographs, and intraoperative photographs of a patient who underwent a minimally invasive lateral approach lumbar spine fusion with a subsequent incisional hernia that necessitated laparoscopic repair. RESULTS A 75-year-old woman with a history of low back and left lower extremity pain with radiographic evidence of foraminal stenosis and degenerative spondylolisthesis underwent a successful L4-L5 discectomy with an extreme lateral interbody fusion via a retroperitoneal transpsoas approach. This was supplemented with a posterior minimally invasive surgery instrumented fusion from L4 to L5. The patient reported significant improvement in symptoms on initial follow-up, however, complained of a prominence over her incision 4 weeks later. An incisional hernia was diagnosed and subsequently repaired laparoscopically, from which the patient recovered uneventfully. CONCLUSIONS Postoperative incisional hernia after extreme lateral interbody fusion is a complication that has not been previously described in the literature but is one that spine surgeons must recognize. This case may prompt surgeons to use a more posterior approach to avoid this complication. Additionally, direct repair of the transversalis fascia is critical to avoiding this complication.

Reducing surgical site infection in spinal surgery with betadine irrigation and intrawound vancomycin powder.

Study Design. Retrospective analysis. Objective. The objective of this study was to evaluate the efficacy of a surgical site infection (SSI) prevention protocol instituted in the Orthopaedic Spine Department at our institution. Summary of Background Data. SSI is an undesired complication of orthopedic spine surgical procedures. It poses a significant risk to the patient, as well as a financial toll on the health care system. A wide range of prophylactic measures have been used to attempt to reduce SSI rates. Methods. A protocol consisting of a combination of 0.3% Betadine wound irrigation and 1 g of intrawound Vancomycin powder application was developed at our institution. Multiple data sources were consolidated for thorough evaluation of changes in SSI rates, patient risk factors, and changes in bacteriology. Identification of risk factors that predispose patients to SSI was performed using mixed-effects logistic regression in a univariate fashion. Risk factors with P values of 0.05 or less in univariate analysis were included together in a multivariate mixed-effects logistic regression model. Results. SSI rates were reduced by 50% after the intervention; &khgr;2 analysis comparing the SSI rates between the pre- and postintervention periods yielded a P value of 0.042. Rates of methicillin-resistant Staphylococcus aureus dropped from 30% to 7% and the rates of multibacterial infections dropped from 37% to 27%. The risk factors that were statistically significant in multivariate analysis were the following: age (odds ratio [OR] = 0.93), anemia (OR = 30.73), prior operation (OR = 27.45), and vertebral fracture (OR = 22.22). Conclusion. The combination of Betadine wound irrigation and intrawound vancomycin powder application led to both a clinically and statistically significant decrease in SSI rates by 50%. Bacteriology analysis and risk factor assessment proved to be valuable tools in assessing the efficacy of a new prophylactic measure and in the planning of future protocols. Level of Evidence: 4

Traumatic Spondylopelvic Dissociation: A Report of Two Cases of Spondylolisthesis at L5-S1 and Review of Literature.

Study Design Retrospective chart review and review of literature. Objective Few case reports of traumatic L5–S1 displacement have been presented in the literature. Here we present two cases of traumatic spondylolisthesis showing both anterior and posterior displacement, the treatment algorithm, and a review of the literature. Methods The authors conducted a retrospective review of representative patients and a literature review of traumatic spondylolisthesis at the L5–S1 junction. Two representative patients were identified with traumatic spondylolisthesis: one with an anterior dissociation, and the other with a posterior dissociation. Results Radiographic, computed tomography, and magnetic resonance imaging illustrated the bony and soft tissue injury found in each patient, as well as the final stabilization and outcomes. Operative stabilization was necessary, and both patients were treated with open reduction internal fixation. The patient with posterior dissociation had complete recovery without neurologic sequelae. The patient with anterior dissociation had persistent bilateral L5–S1 radiculopathy with intact rectal tone, due to neurologic compression. Conclusions Few cases of traumatic spondylopelvic dissociation that are isolated to the L5–S1 disk space are described in the literature. We examined both an anterior and a posterior dissociation and treated both with L5–S1 posterior spinal fusion. The patient with anterior dissociation had persistent L5–S1 root injury; however, the patient with posterior dissociation had no neurologic deficits. This is the opposite of what is expected based on anatomy. These cases offer insight into the management of anterior and posterior L5–S1 spondylopelvic dissociation.

Kinematics of Progressive Circumferential Ligament Resection (Decompression) in Conjunction With Cervical Disc Arthroplasty in a Spondylotic Spine Model

Study Design. Benchtop biomechanics study examining kinematic effects of progressive resection in a human cadaveric spine model. Objective. To determine the effects of posterior longitudinal ligament (PLL) resection, unilateral and bilateral foraminotomy, and laminectomy on cervical intervertebral rotation and translation after cervical disc arthroplasty (CDA). Summary of Background Data. Although the clinical results after CDA have been studied, there remain unanswered questions regarding the surgical techniques used at the time of device insertion. For example, it is unclear whether a surgeon should retain or resect the PLL and uncinate processes at the time of primary surgical intervention. Further, the effect of a subsequent posterior decompression (foraminotomy or laminectomy) on the stability of a motion segment containing a disc arthroplasty is unknown. Methods. Three-dimensional intervertebral motion was measured by biplanar videography in human cadaveric spines at C4–C5 or at C5–C6 subjected to a 1.5-Nm moment applied to induce motion in the sagittal plane. Coupled motions were not constrained. After measuring intact spine motion, disc arthroplasty with bilateral ventral foraminotomy was performed without PLL resection. Sequentially, rotations and translations were measured after PLL resection, unilateral foraminotomy, bilateral foraminotomy, and laminectomy. Results. CDA with bilateral ventral foraminotomy increased sagittal rotation by 0.4° (16%) compared with the intact spine. The addition of PLL resection increased rotation by 0.5° (14% increase). Unilateral and bilateral foraminotomy had negligible effects on sagittal rotation or anteroposterior (AP) translation. Laminectomy resulted in an additional sagittal plane rotation of 2°. The sagittal-plane interverterbal rotation resultant after all interventions was 6°, with 1.5 mm of AP translation occurring only. Conclusion. Given that a greater degree of motion was seen with PLL resection combined with ventral foraminotomy, we recommend that PLL resection be performed when performing CDA. In our benchtop model, unilateral and bilateral posterior foraminotomies were not associated with the creation of significant sagittal rotational or AP translational instability.

A biomechanical comparison of three spondylolysis repair techniques in a calf spine model.

SUMMARY OF BACKGROUND DATA Previous work has demonstrated the efficacy of lumbar pedicle screw hook rod (PSHR) techniques and the Buck screw in the stabilization of spondylolysis. The mechanical behavior of lower profile cervical implants used to create PSHR, hybrid cable plate constructs, and titanium miniplating has not previously been described. METHODS Calf lumbar spines (L2-L6) were utilized for testing (n=27). Intervertebral rotation was measured in the intact spines across the L4-5 segment before and after creation of bilateral pars interarticularis defects. Defects were then stabilized with one of three repair techniques, PSHR, miniplate, or cable plate (CP) constructs. (n=9). A 5-Nm load was applied in flexion-extension, lateral bending and axial rotation. Fracture displacement was measured under flexion-extension and lateral bending modes. RESULTS Osteotomy of the pars interarticularis increased intervertebral rotation from 4.6° to 9.2° (P<.05). The three techniques of repair reduced intervertebral rotation without statistical superiority of one method. In lateral bending the miniplate was most effective in reducing pars defect displacement (0.6mm, P<0.05). Although, the miniplate provided lower defect displacement in flexion-extension and axial rotation, these differences were not statistically significant. CONCLUSIONS Bilateral miniplate fixation demonstrates superiority in restoring stability in lateral bending as compared to pedicle screw hook rod techniques and cable plate constructs. In flexion-extension and axial rotation, it was as effective as a PSHR method. Consideration of anatomic plate designs warrants consideration. LEVEL OF EVIDENCE IV.

Patient and surgeon factors associated with postoperative kyphosis after laminoplasty.

Expansive cervical laminoplasty began its evolution in the 1970s in Japan for the treatment of cervical spondylotic myelopathy secondary to ossification of posterior longitudinal ligament or cervical spondylosis. The goal of the procedure is to reduce the complications associated with the inherent destabilization associated with laminectomy while preserving cervical spine range of motion.1 It has also been established in the literature that preoperative kyphotic deformity is a risk factor for poor surgical outcome and neurological recovery.2,3 We hypothesize that meticulous preservation of the interspinous ligaments may help prevent iatrogenic kyphosis.

Perioperative Patient Management of Adult Lumbar Scoliosis

Adult spinal deformity (ASD) surgery requires significant interventions as have been outlined in the previous chapters. With these larger surgeries, attention to detail and pre- and postsurgical planning are critical. The spinal surgeon must preemptively intervene to minimize the risks of commonly occurring complications. In this chapter we will try to delineate the interventions that are undertaken in the perioperative period that have been shown through literature or personal experience to minimize complications.

Treatment of Spine Deformity in Neuromuscular Diseases

Surgical management of spinal deformity in neuromuscular diseases (NMDs) often requires a multidisciplinary approach beginning in the preoperative surgical planning period, owing to concomitant restrictive lung disease and cardiomyopathy in selected NMD conditions. The need for thorough and thoughtful discussions must occur with the family and other caregivers before any scheduled surgery. The decision to proceed with spinal instrumentation may alter functional abilities in weak and marginally ambulatory NMD patients. With care and treatment involving a multidisciplinary team, proper planning, and support, patients will likely experience rewarding outcomes and improved quality of life.