Intravenous Ketorolac Substantially Reduces Opioid Use and Length of Stay After Lumbar Fusion: A Randomized Controlled Trial

STUDY DESIGN

A randomized, double-blinded, placebo-controlled trial.

OBJECTIVE

To examine the effect of intravenous ketorolac (IV-K) on hospital opioid use compared with IV-placebo (IV-P) and IV acetaminophen (IV-A).

SUMMARY OF BACKGROUND DATA

Controlling postoperative pain while minimizing opioid use after lumbar spinal fusion is an important area of study.

PATIENTS AND METHODS

Patients aged 18 to 75 years undergoing 1 to 2 level lumbar fusions between April 2016 and December 2019 were included. Patients with chronic opioid use, smokers, and those on systemic glucocorticoids or contraindications to study medications were excluded. A block randomization scheme was used, and study personnel, hospital staff, and subjects were blinded to the assignment. Patients were randomized postoperatively. The IV-K group received 15 mg (age > 65) or 30 mg (age < 65) every six hours (q6h) for 48 hours, IV-A received 1000 mg q6h, and IV-P received normal saline q6h for 48 hours. Demographic and surgical details, opioid use in morphine milliequivalents, opioid-related adverse events, and length of stay (LOS) were recorded. The primary outcome was in-hospital opioid use up to 72 hours.

RESULTS

A total of 171 patients were included (58 IV-K, 55 IV-A, and 58 IV-P) in the intent-to-treat (ITT) analysis, with a mean age of 57.1 years. The IV-K group had lower opioid use at 72 hours (173 ± 157 mg) versus IV-A (255 ± 179 mg) and IV-P (299 ± 179 mg; P = 0.000). In terms of opiate use, IV-K was superior to IV-A ( P = 0.025) and IV-P ( P = 0.000) on ITT analysis, although on per-protocol analysis, the difference with IV-A did not reach significance ( P = 0.063). When compared with IV-P, IV-K patients reported significantly lower worst ( P = 0.004), best ( P = 0.001), average ( P = 0.001), and current pain ( P = 0.002) on postoperative day 1, and significantly shorter LOS ( P = 0.009) on ITT analysis. There were no differences in opioid-related adverse events, drain output, clinical outcomes, transfusion rates, or fusion rates.

CONCLUSIONS

By reducing opioid use, improving pain control on postoperative day 1, and decreasing LOS without increases in complications or pseudarthrosis, IV-K may be an important component of "enhanced recovery after surgery" protocols.

Inducing Angiogenesis in the Nucleus Pulposus

Bone morphogenetic protein (BMP) gene delivery to Lewis rat lumbar intervertebral discs (IVDs) drives bone formation anterior and external to the IVD, suggesting the IVD is inhospitable to osteogenesis. This study was designed to determine if IVD destruction with a proteoglycanase, and/or generating an IVD blood supply by gene delivery of an angiogenic growth factor, could render the IVD permissive to intra-discal BMP-driven osteogenesis and fusion. Surgical intra-discal delivery of naïve or gene-programmed cells (BMP2/BMP7 co-expressing or VEGF165 expressing) +/- purified chondroitinase-ABC (chABC) in all permutations was performed between lumbar 4/5 and L5/6 vertebrae, and radiographic, histology, and biomechanics endpoints were collected. Follow-up anti-sFlt Western blotting was performed. BMP and VEGF/BMP treatments had the highest stiffness, bone production and fusion. Bone was induced anterior to the IVD, and was not intra-discal from any treatment. chABC impaired BMP-driven osteogenesis, decreased histological staining for IVD proteoglycans, and made the IVD permissive to angiogenesis. A soluble fragment of VEGF Receptor-1 (sFlt) was liberated from the IVD matrix by incubation with chABC, suggesting dysregulation of the sFlt matrix attachment is a possible mechanism for the chABC-mediated IVD angiogenesis we observed. Based on these results, the IVD can be manipulated to foster vascular invasion, and by extension, possibly osteogenesis.

Lumbar spine intervertebral disc gene delivery of BMPs induces anterior spine fusion in lewis rats

Minimally invasive techniques and biological autograft alternatives such as the bone morphogenetic proteins (BMPs) can reduce morbidity associated with spinal fusions. This study was a proof-of-concept for gene-therapy-mediated anterior spine fusion that could be adapted to percutaneous technique for clinical use. Isogeneic bone marrow stromal cells genetically programmed to express b-galactosidase (LACZ, a marker gene), BMP2, BMP7, a mixture of BMP2 and BMP7 infected cells (homodimers, HM), or BMP2/7 heterodimers (HT) were implanted into the discs between lumbar vertebrae 4 and 5 (L4/5) and L5/6 of male Lewis rats. Spine stiffening was monitored at 4, 8 and 12 weeks using noninvasive-induced angular displacement (NIAD) testing. At 12 weeks isolated spines were assessed for fusion and bone formation by palpation, biomechanical testing [four-point bending stiffness, moment to failure in extension, and in vitro angular displacement (IVAD)], faxitron x-rays, microCT, and histology. Progressive loss of NIAD occurred in only the HT group (p < 0.001), and biomechanical tests correlated with the NIAD results. Significant fusion occurred only in the HT group (94% of animals with one or both levels) as assessed by palpation (p < 0.001), which predicted HT bone production assessed by faxitron (p ≤ 0.001) or microCT (p < 0.023). Intervertebral bridging bone was consistently observed only in HT-treated specimens. Induced bone was located anterior and lateral to the disc space, with no bone formation noted within the disc. Percutaneous anterior spine fusions may be possible clinically, but induction of bone inside the disc space remains a challenge.

Unplanned Reoperations Affect Long-Term Outcomes in Adult Spinal Deformity Patients Undergoing Long Fusions to the Sacrum

STUDY DESIGN

Retrospective clinical cohort study.

OBJECTIVE

To compare the long-term complications and outcomes scores of primary and revision surgeries for adult spinal deformity of patients treated with long fusions to the sacrum.

SUMMARY OF BACKGROUND DATA

Long fusions in patients with adult spinal deformity are fraught with complications and the need for reoperation that can significantly impact patient health-related quality of life.

METHODS

Data from 134 consecutive patients who underwent spinal fusion from the thoracic spine to the sacropelvis and had a minimum of 5-year follow-up were analyzed. Patients were classified as primary surgery (PS) and index revision (IR) surgery; they were then subdivided based on whether they returned to the operating room (RTO) or not (NRTO). RTO complications were classified as 1) infection, 2) neurologic, 3) fusion status, 4) implants, and 5) global alignment and stratified as <6 months, <2 years, and >2 years. Final Scoliosis Research Society Patient Questionnaire (SRS 22r) and Oswestry Disability Index (ODI) scores were compared between subgroups.

RESULTS

Seventy-one PS and 63 IR were included in the analysis. Mean age at surgery was 54.9 years (30-78), mean follow-up 5.8 years (4.9-12.8). RTO rates were 21.1% and 34.9%, respectively, for PS and IR (p = .16). 43.8% of patients requiring reoperation did so on multiple occasions. Fifty PS and 41 IR cases had complete SRS 22 and ODI scores. Final SRS 22 total scores were 3.74 and 3.41 (p = .02) for the respective groups. ODI scores were 25.4% and 34.0% (p = .02).

CONCLUSIONS

Both groups had a significant number of revision surgeries performed by 5 years of follow-up. Unplanned reoperation significantly affected ODI and SRS 22 outcomes scores in the individual domains of pain, function, and overall satisfaction as well as total score at the 5-year follow-up regardless of PS or IR status. Overall, the PS group had improved outcomes when compared to the IR group.

Lumbar spine intervertebral disc gene delivery: a pilot study in lewis rats

BACKGROUND

Basic research toward understanding and treating disc pathology in the spine has utilized numerous animal models, with delivery of small molecules, purified factors, and genes of interest. To date, gene delivery to the rat lumbar spine has only been described utilizing genetically programmed cells in a matrix which has required partial disc excision, and expected limitation of treatment diffusion into the disc.

PURPOSE

This study was designed to develop and describe a surgical technique for lumbar spine exposure and disc space preparation, and use of a matrix-free method for gene delivery.

METHODS

Naïve or genetically programmed isogeneic bone marrow stromal cells were surgically delivered to adolescent male Lewis rat lumbar discs, and utilizing quantitative biochemical and qualitative immunohistological assessments, the implanted cells were detected 3 days post-procedure.

RESULTS

Statistically significant differences were noted for recovery of the β-galactosidase marker gene comparing delivery of naïve or labeled cells (10(5) cells per disc) from the site of implantation, and between delivery of 10(5) or 10(6) labeled cells per disc at the site of implantation and the adjacent vertebral body. Immunohistology confirmed that the β-galactosidase marker was detected in the adjacent vertebra bone in the zone of surgical implantation.

CONCLUSIONS

The model requires further testing in larger cohorts and with biologically active genes of interest, but the observations from the pilot experiments are very encouraging that this will be a useful comparative model for basic spine research involving gene or cell delivery, or other locally delivered therapies to the intervertebral disc or adjacent vertebral bodies in rats.

Stromal derived factor-1 regulates bone morphogenetic protein 2-induced osteogenic differentiation of primary mesenchymal stem cells

Stromal derived factor-1 (SDF-1) is a chemokine signaling molecule that binds to its transmembrane receptor CXC chemokine receptor-4 (CXCR4). While we previously detected that SDF-1 was co-required with bone morphogenetic protein 2 (BMP2) for differentiating mesenchymal C2C12 cells into osteoblastic cells, it is unknown whether SDF-1 is similarly involved in the osteogenic differentiation of mesenchymal stem cells (MSCs). Therefore, here we examined the role of SDF-1 signaling during BMP2-induced osteogenic differentiation of primary MSCs that were derived from human and mouse bone marrow. Our data showed that blocking of the SDF-1/CXCR4 signal axis or adding SDF-1 protein to MSCs significantly affected BMP2-induced alkaline phosphatase (ALP) activity and osteocalcin (OCN) synthesis, markers of preosteoblasts and mature osteoblasts, respectively. Moreover, disrupting the SDF-1 signaling impaired bone nodule mineralization during terminal differentiation of MSCs. Furthermore, we detected that blocking of the SDF-1 signaling inhibited the BMP2-induced early expression of Runt-related factor-2 (Runx2) and osterix (Osx), two "master" regulators of osteogenesis, and the SDF-1 effect was mediated via intracellular Smad and Erk activation. In conclusion, our results demonstrated a regulatory role of SDF-1 in BMP2-induced osteogenic differentiation of MSCs, as perturbing the SDF-1 signaling affected the differentiation of MSCs towards osteoblastic cells in response to BMP2 stimulation. These data provide novel insights into molecular mechanisms underlying MSC osteogenesis, and will contribute to the development of MSC therapies for enhancing bone formation and regeneration in broad orthopaedic situations.

A novel regulatory role for stromal-derived factor-1 signaling in bone morphogenic protein-2 osteogenic differentiation of mesenchymal C2C12 cells

Stromal-derived factor 1 (SDF-1) is a chemokine with important functions in development and postnatal tissue homeostasis. SDF-1 signaling via the G-protein-coupled receptor CXCR4 regulates the recruitment of stem and precursor cells to support tissue-specific repair or regeneration. In this study we examined the contribution of SDF-1 signaling to osteogenic differentiation of mesenchymal C2C12 cells induced by bone morphogenic protein 2 (BMP2). Blocking SDF-1 signaling before BMP2 stimulation by treatment with siRNA, antibodies against SDF-1 or CXCR4, or the G-protein-coupled receptor inhibitor pertussis toxin strongly suppressed BMP2 induction of osteogenic differentiation in C2C12 cells, as evidenced by an early decrease in the expression of the myogenesis inhibitor Id1, the osteogenic master regulators Runx2 and Osx, the osteoblast-associated transcription factors JunB, Plzf, Msx2, and Dlx5, and later of the bone marker proteins osteocalcin and alkaline phosphatase. Similarly, blocking SDF-1/CXCR4 signaling strongly inhibited BMP2-induced osteogenic differentiation of ST2 bone marrow stromal cells. Moreover, we found that the interaction between SDF-1 and BMP2 signaling was mediated via intracellular Smads and MAPK activation. Our data provide the first evidence for a co-requirement of the SDF-1/CXCR4 signaling axis in BMP2-induced osteogenic differentiation of C2C12 and ST2 cells and, thus, uncover a new potential target for modulation of osteogenesis.

A Novel Source of Cancellous Autograft for ACDF Surgery: The Manubrium

There are a variety of techniques and biologic options when performing interbody fusion during an anterior cervical discectomy and fusion (ACDF). Autologous graft provides high rates of fusion; however, complications associated with donor site morbidity from the iliac crest have prompted some surgeons to use alternative graft material. Ten patients (8 men, 2 women) with cervical radiculopathy underwent single-level ACDF with plate fixation, titanium mesh cage, and cancellous autograft from the manubrium. Cancellous bone was obtained through a cortical window on the anterior aspect of the manubrium through a 2-cm transverse incision. A minimum 1-year clinical and radiographic follow-up for all patients evaluated fusion rates, donor site morbidity, and patient satisfaction. All patients had immediate postoperative resolution of radicular symptoms and radiographic evidence of solid fusion within 3 months. No patient complained of donor site pain and narcotic pain medication was not required after discharge. No complications associated with the manubrium donor site were noted; however, 1 female patient was dissatisfied with its cosmetic appearance. The manubrium is an effective, safe, and technically facile source of autologous bone graft that yields high fusion rates and patient satisfaction in contemporary ACDF surgery. This new technique to obtain cancellous graft from the manubrium combines the advantages of autologous bone without the morbidity of iliac crest harvest.

Comprehensive Analysis of Cantilever, Translational, and Modular Corrective Techniques in Adults with Scoliosis Treated with Surgery to the Sacropelvis

BACKGROUND

The treatment of adults with scoliosis has been the source of debate over the last several decades. Pain associated with curve progression and decompensation is the most common presenting scenario and surgical management is often indicated. Correction of these deformities may involve long segment fusions to the sacrum and pelvis. Most authors have reported high rates of complications associated with this procedure. There remains little consensus with regard to the treatment of this challenging condition.

PURPOSE

The purpose of this study was to evaluate the clinical and radiographic outcomes of patients treated with long fusions to the sacrum and pelvis using third generation instrumentation techniques. These included the use of cantilever, translational, and modular corrective techniques.

METHODS

Inpatient and outpatient charts were reviewed for 97 patients (89 women and 8 men). The average age was 55 years (27 to 78 y). The information obtained included patient age, sex, comorbidities, perioperative complications, and long-term clinical outcome. Standing radiographic coronal and sagittal measurements were recorded preoperatively, immediately postoperatively, and at the most recent follow-up visit.

RESULTS

Eighty-nine patients underwent combined anterior and posterior surgery, whereas 8 patients were treated with posterior-only procedures. Two patients had fixation to the sacrum without extension into the ilium. Structural curves averaged 53 degrees preoperatively, 32 degrees postoperatively, and 33 degrees at follow-up. Thoracic kyphosis averaged +36 degrees preoperatively, +39 degrees postoperatively, and +46 degrees at follow-up. Lumbar lordosis averaged -41 degrees preoperatively, -48 degrees postoperatively, and -48 degrees at follow-up. Coronal imbalance averaged 2.9 cm preoperatively, 2.4 cm postoperatively, and 2.3 cm at follow-up. Sagittal imbalance averaged 6.8 cm preoperatively, 2.9 cm postoperatively, and 3.6 cm at follow-up. Major complications included pseudarthrosis (10%), deep infection (13%), painful iliac fixation (20%), neurologic injury (6%), need for some form of revision surgery (39%), chronic severe pain (2%), pulmonary embolism (2%), and deep venous thrombosis (2%). There were no permanent neurologic injuries or deaths related to the surgery.

Noggin regulation of bone morphogenetic protein (BMP) 2/7 heterodimer activity in vitro

Bone morphogenic proteins (BMPs) are growth factors important for skeletal development and bone growth. Noggin, one of the soluble BMP antagonists, regulates the action of BMPs on mesenchymal precursor cells, partially through a feedback type of inhibition. In this study, we constructed a novel BMP2/7 'fusion gene' that encodes both BMP2 and BMP7 genes in tandem by a linker. Polymerase chain reaction (PCR) and Western blotting showed that the BMP2/7 fusion gene construct led to the production of BMP2/7 heterodimers in A549 'producer' cells. When applied to C2C12 myoblastic cells, BMP2/7 heterodimers increased alkaline phosphatase (ALP) activity and osteocalcin (OCN) expression (markers of osteoblastic differentiation) more effectively than either BMP2 or BMP7 homodimers. Moreover, this heterodimer induced significantly lower levels of Noggin expression in C2C12 cells than respective homodimers at similar doses. The addition of Noggin did not affect the heterodimer's activities in increasing osteoblastic differentiation in C2C12 cells. In contrast, BMP2 and BMP7 homodimers were largely inhibited by Noggin. Our finding suggests that the 'fusion gene' construct led to the production of bioactive BMP2/7 heterodimers, which were not antagonized by Noggin as effectively as it to BMP homodimers. The weaker Noggin antagonism on BMP heterodimers compared to homodimers may contribute to increased osteogenic potency of heterodimers in vitro and in vivo.

The treatment of large (>70 degrees) thoracic idiopathic scoliosis curves with posterior instrumentation and arthrodesis: when is anterior release indicated?

STUDY DESIGN

Retrospective clinical study from 2 centers.

OBJECTIVE

To analyze the efficacy of posterior instrumentation and arthrodesis for thoracic idiopathic scoliosis curves more than 70 degrees.

SUMMARY OF BACKGROUND INFORMATION

The increasing use of thoracoscopic techniques in deformity surgery has led several investigators to advocate anterior release followed by posterior instrumentation when treating "stiff" thoracic curves 60 degrees-70 degrees. To our knowledge, no study has been published to define indications for anterior surgery in thoracic idiopathic scoliosis.

METHODS

This is a retrospective review of patients 20 years and younger, with idiopathic scoliosis and thoracic curves more than 70 degrees treated with isolated posterior instrumentation and arthrodesis at 2 institutions from 1989 to 1999. A total of 50 patients were identified, and 46 were available for minimum 2-year radiographic follow-up. Of the 50 patients, 44 had bend films taken before surgery. All patients were treated with third-generation segmental spinal instrumentation using a varied combination of hooks, wires, and screws.

RESULTS

Average patient age at surgery was 14.4 years (range 10-20), and average radiographic follow-up was 4.4 years (range 2-11.5). Average preoperative thoracic curve was 75 degrees (range 70 degrees-88 degrees), and average bend was 47 degrees (range 28 degrees-60 degrees), a flexibility of 37%. Average postoperative curve was 25 degrees (range 10 degrees-46 degrees), and it was 27 degrees (range 11 degrees-46 degrees) at latest follow-up, a correction of 64%. The average length of surgery was 6.15 hours, mean hospital stay was 8 days, and average blood loss was 1100 cc. The Scoliosis Research Society 22 or 24 was available at a minimum of 2 years in 46 of 50 patients. Mean domain scores were: pain 4.4, self-image 4.3, function 4.3, mental health 4.3, satisfaction 4.7, and total 4.4. Complications included 1 pseudarthrosis, 1 implant removal for prominence, and 1 implant removal for late operative site pain.

CONCLUSION

Using posterior surgery only, we have been able to at least equal the results reported in the literature by investigators using combined approaches. Isolated posterior instrumentation and arthrodesis achieve satisfactory cosmetic, radiographic, and patient-based outcomes in adolescents with idiopathic scoliosis with thoracic curves 70 degrees-90 degrees, without the added expense and morbidity of anterior release.

Not all spondylolisthesis grading instruments are reliable

Spondylolisthesis is the slippage of one vertebral body on an adjacent level, and occurs commonly at the lumbosacral junction in children. Many radiographic measurement instruments have been described to predict progression and need for intervention. We evaluated the reliability of eight common grading instruments. Four raters reviewed 30 lateral radiographs of the lumbar spine in patients with spondylolisthesis. Each rater measured each film twice, and had mean individual correlation coefficients of at least 0.76 (range, 0.76-0.91). Only three measurements had interobserver correlations greater than 0.75 (slip percentage, Meyerding's grade, and sacral inclination), which corresponded to excellent reliability. For intraobserver reliability, six measurements had correlations greater than 0.75 (all except kyphosis angle and lumbar index), indicating excellent agreement. Slip percent, Meyerding's grade, and sacral inclination had excellent interobserver agreement and intraobserver agreement.

Combined bone morphogenetic protein-2 and -7 gene transfer enhances osteoblastic differentiation and spine fusion in a rodent model

To enhance the osteogenic activity of BMP, combination BMP2 and BMP7 gene transfer was performed. This approach led to a significant increase in osteoblastic differentiation of mesenchymal precursors compared with single BMP gene transfer in vitro. When tested in 78 rats, combination gene transfer enhanced mechanically stable spine fusion and bone formation rate versus single BMP gene transfer.

INTRODUCTION

Although clinical bone morphogenetic protein (BMP) therapy is effective, required doses are very high. Previous studies have suggested that the co-expression of two different BMP genes can result in the production of heterodimeric BMPs that may be more potent than homodimers. In this study, combined BMP2 and BMP7 gene transfer was performed to test whether this approach improves osteoblastic differentiation and bone formation compared with single BMP gene transfer.

MATERIALS AND METHODS

A producer cell (A549) was co-transfected with adenovirus vectors encoding BMP2 (AdBMP2) and BMP7 (AdBMP7) or, as controls, each vector alone, AdNull (with no transgene) or no virus. Supernatants were compared for their ability to stimulate osteoblastic differentiation of C2C12 myoblasts and MC3T3-E1 pre-osteoblasts. In a rat posterolateral spine fusion model, co-administration of AdBMP2 and AdBMP7 was compared with treatment with each vector alone, AdNull or no virus in 78 rats. The spines were assessed 8 weeks after surgery for radiographic and mechanical fusion, bone formation, and mineralization.

RESULTS

BMP2 and BMP7 were co-precipitated from supernatants of cells co-transfected with AdBMP2 and AdBMP7, indicating the presence of BMP2/7 heterodimer. Supernatants of co-transfected cells containing relatively low doses (7-140 ng/ml) of BMPs induced osteocalcin expression and alkaline phosphatase activity in both C2C12 and MC3T3-E1 cells, that were up to 6- and 40-fold higher, respectively, than levels induced by maximal doses (200-1000 ng/ml) of either BMP2 or BMP7 alone. In the spine fusion model, co-administration of AdBMP2 and AdBMP7 resulted in a significantly greater number of mechanically stable fusions and also 2-fold higher mineralization rate and bone volume in the fusion mass versus single BMP gene transfer (p < 0.02, all comparisons).

CONCLUSION

Combined BMP2 and BMP7 gene transfer is significantly more effective in inducing osteoblastic differentiation and spine fusion than individual BMP gene transfer.

Scheuermann kyphosis: safe and effective surgical treatment using multisegmental instrumentation

STUDY DESIGN

A retrospective review was conducted on 23 consecutive patients who underwent surgical correction of Scheuermann kyphosis using modern multisegmental instrumentation.

OBJECTIVE

To evaluate Scheuermann kyphosis correction and complication rates.

SUMMARY OF BACKGROUND DATA

The surgical treatment of Scheuermann kyphosis remains a topic of debate. The literature of the 70s and 80s on the surgical management of this disorder using Harrington instrumentation demonstrated that operative correction is quite effective but associated with significant complications. This literature, however, may be less applicable to current clinical situations. The use of modern multisegmental instrumentation and increased awareness of potential complications may decrease the risks of current operative treatment.

METHODS

Hospital charts, office charts, and radiographs on 23 consecutive patients who underwent operative treatment using multisegmental instrumentation for Scheuermann kyphosis were reviewed to identify complications of surgery. Complications were classified as minor, major, or life threatening.

RESULTS

The mean follow-up was 38 months (range 10-123 months). Preoperative kyphosis ranged from 63 degrees to 104 degrees with an average of 83 degrees. Twenty of the 23 patients (87%) underwent combined anterior release/arthrodesis with posterior arthrodesis/multisegmental instrumentation. The remaining 3 patients underwent posterior arthrodesis/multisegmental instrumentation. Postoperative total kyphosis ranged from 32 degrees to 67 degrees with an average of 46 degrees. At final follow-up, the total kyphosis ranged from 37 degrees to 75 degrees with an average of 51 degrees. Overall, we had 43% minor complications, 17% major complications, and 0% life-threatening complications.

CONCLUSIONS

Surgical correction of Scheuermann kyphosis can be performed safely and effectively using modern multisegmental instrumentation.

Functional and radiographic outcomes after surgery for adult scoliosis using third-generation instrumentation techniques

STUDY DESIGN

Retrospective radiograph and chart review of 28 patients with adult idiopathic scoliosis undergoing primary corrective surgery. Clinical and radiographic parameters were assessed before surgery, after surgery, and at a 2-year follow-up assessment. A self-perceived outcome questionnaire was administered to the study patients at a minimum 2-year follow-up assessment.

OBJECTIVE

To assess patient outcomes after surgery for adult scoliosis using traditional radiographic parameters along with a self-perceived outcomes questionnaire.

SUMMARY OF BACKGROUND DATA

The clinical and radiographic results and the outcomes for the surgical treatment of adult idiopathic scoliosis have not been established in the literature with respect to the use of modern third-generation instrumentation techniques. Most studies reviewing the surgical treatment of adult idiopathic scoliosis look primarily at Harrington instrumentation techniques.

METHODS

Records and radiographs were reviewed retrospectively for all the patients (n = 54) undergoing primary corrective surgery for adult idiopathic scoliosis between December 30, 1994 and December 30, 1997. Of the 54 patients reviewed, 28 (52%) met the following inclusion criteria: age exceeding 20 years, primary surgery, fusion above the sacrum, availability of medical records along with preoperative, postoperative, and 2-year follow-up radiographs. Additionally, a self-perceived outcomes questionnaire was administered to these patients at a minimum 2-year follow-up assessment.

RESULTS

All the patients were women (28/28). The indications for surgery were pain and progression in 54% (15/28) and pain in 29% (8/28) of the patients. The average preoperative major curve measurement was 65 degrees (range, 38-98 degrees ). The average postoperative major curve measurement was 24 degrees (range, 5-59 degrees ), for a correction of 64%. The average follow-up curve measurement was 27 degrees (range, 3-60 degrees ), for a correction of 61%. Whereas 71% of the cases were anteroposterior, 29% were posterior only. There was one intraoperative complication among the 28 patients and four postoperative complications in 3 of the 28 patients. The self-perceived outcome questionnaires were available for 83% (23/28) of the patients. Definite or probable relief of symptoms was reported in 74%(17/23). Improved ability to sleep was reported in 61% (14/23), and ability to return to their usual job was reported in 57% (13/23). Satisfaction with the results of surgery was reported in 87% (20/23).

CONCLUSIONS

Surgery for adult idiopathic scoliosis using third-generation instrumentation techniques provides significant clinical improvement, scoliosis correction, maintenance of sagittal alignment, and patient satisfaction, with an acceptable complication rate.

Partial lumbosacral kyphosis reduction, decompression, and posterior lumbosacral transfixation in high-grade isthmic spondylolisthesis: clinical and radiographic results in six patients

BACKGROUND

In an attempt to increase fusion while decreasing the neurologic risk associated with complete reduction of high-grade spondylolisthesis, the authors have used a technique of partial lumbosacral kyphosis reduction, posterior decompression, and pedicle screw transfixation of the lumbosacral junction.

OBJECTIVE

To determine if this technique is effective in treatment of high-grade spondylolisthesis.

STUDY DESIGN

A retrospective review of six patients with high-grade spondylolisthesis treated by this technique was performed. There were four female patients (ages 16 years [n=2], 23 years [n=1], and 29 years [n=1]) and two male patients (both 13 years of age) with spondylolisthesis ranging from Grade IV to Grade V. All patients presented with pain and radiculopathy. After surgery the patients were evaluated for resolution of symptoms, sagittal alignment, fusion, and satisfaction. The radiographic measurements included the slip angle, the percentage slip, and the sacral inclination. An SRS outcome score was also obtained on all six patients to evaluate postoperative outcome, in terms of pain control, self-image perception, and return to function.

RESULTS

The average length of follow-up was 42.6 months (range 24-60 months). All patients evidenced solid fusion by the 6-month follow-up (based on oblique radiographs showing lateral bridging bone masses). The slip angle was improved from 62 degrees to 28 degrees (P < 0.5), whereas there was no significant improvement in the percentage slip or the sacral inclination (89-80% and 28-37 degrees, respectively). No progression of the slip angle or percentage slip was noted on the follow-up radiographs. Complications included two intraoperative dural tears that were identified and repaired. There were no neurologic complications. The SRS outcome instrument demonstrated good postoperative pain control, function, self-image, and satisfaction in all patients.

CONCLUSION

In high-grade spondylolisthesis, this posterior approach is safe and effective in obtaining a solid arthrodesis, restoring sagittal balance, and improving function. These results reinforce the impression that it is the partial reduction of the slip angle, not the percentage slip, in high-grade spondylolisthesis that is important in obtaining optimal results.

Spinal epidural hemangioma related to pregnancy

We report the case of a 39-year-old woman with adolescent idiopathic scoliosis presenting with myelopathy secondary to a spinal epidural hemangioma. MRI showed an epidural soft tissue mass within the spinal canal between T5 and T9 with severe spinal cord compression. Symptoms had a temporal relationship to her pregnancy. Surgical removal of the epidural hemangioma rapidly relieved her symptoms and neurologic deficits. Follow-up examination 2 years later demonstrated normal motor and sensory function, without any neurologic sequelae or progression of deformity.

Surgical treatment of adolescent idiopathic scoliosis: a comparative study of two segmental instrumentation systems

This study compares two different surgical techniques and instrumentation types in the treatment of adolescent idiopathic scoliosis. The charts and radiographs of 116 patients with adolescent idiopathic scoliosis treated by posterior spine fusion with Isola or Cotrel-Dubousset instrumentation were reviewed. Patients were separated into two equivalent groups matched for age, sex, curve type, and curve magnitude. All patients had a minimum of 2 years follow-up. The instrumentation in group 1 consisted of hooks, wires, and pedicle screws. That used in group 2 was limited to hooks and rods. The Mann-Whitney, Wilcoxin, and the paired Student t tests for matched pairs were used for statistical analysis. Patients in group 1 had increased curve correction (66% vs. 52%), apical vertebral translation (63% vs. 30%), and correction of the end vertebral tilt angle (11 degrees vs. 3 degrees) (p < 0.001). The percentage of coronal curve correction in curves larger than 65 degrees also was greater in group 1 (59% vs. 40%). Physiologic sagittal alignment was obtained in 80% of the patients in group 1 and 25% in group 2. No major complication or pseudoarthrosis occurred in either group. This study supports improved correction of curve magnitude, apical translation, and end vertebral tilt angle with the use of multiple anchor types compared with the correction achieved with standard hook-and-rod constructs.

Safety and efficacy of pedicle screw placement for adult spinal deformity with a pedicle-probing conventional anatomic technique

A prospective study of 50 adults treated with fusion, realignment, and segmental spinal instrumentation for spinal deformity was conducted to assess the safety, accuracy, and efficacy of the free-hand pedicle screw placement technique. Postoperative computed tomographic scans were performed to evaluate the placement of 282 screws and were correlated with patients' clinical outcomes. Five screws were placed at T12, 26 at L1, 39 at L2, 48 at L3, 73 at L4, 35 at L5, and 50 at S1. Nine screws (3%) were misplaced and included three screws (1.06%) that violated the medial wall with no clinical sequelae or revision surgery needed. There were no neurologic deficits related to screw placement. The free-hand technique is a safe and cost-effective method for pedicular screw placement during surgery for adult spine deformities.

Safety of sublaminar wires with Isola instrumentation for the treatment of idiopathic scoliosis

STUDY DESIGN

To investigate the incidence of acute neurologic complications of use of sublaminar wires with third-generation spine instrumentation for the treatment of idiopathic scoliosis.

OBJECTIVES

To assess the safety of sublaminar wires in the surgical treatment of idiopathic scoliosis.

SUMMARY OF BACKGROUND DATA

The use of sublaminar wires in spine deformity for neuromuscular scoliosis and the Luque system has been reported. Use of sublaminar wires is an integral part of the technique in the surgical treatment of spine deformity with Isola instrumentation (AcroMed, Cleveland, OH). To date, the safety of this technique has not been documented.

METHODS

The average age of the patients was 37 years (range, 11-74 years). Preoperative diagnosis was adolescent idiopathic scoliosis in 75 patients and adult idiopathic scoliosis in 66. One hundred nine were primary surgeries, and 32 were revision. Detailed evaluation of the curve type, curve magnitude, number of vertebrae instrumented, level of vertebrae wired, postoperative neurologic deficit, and the findings of intraoperative spinal cord monitoring was performed. Wires were always passed just before corrective maneuvers were performed.

RESULTS

A total of 1366 wires were placed, 65% (n = 888) in the thoracic region, 22% (n = 300) in the thoracolumbar, and 13% (n = 178) in the lumbar. No permanent change in intraoperative spinal cord monitoring was detected. Stagnara wake-up test was performed in all patients. No patient with adolescent idiopathic scoliosis had neurologic complication. Two adults underwent revision surgery and had transient dysesthesia in the leg, which completely resolved with observation.

CONCLUSION

Despite the increasing complexity of spinal instrumentation systems, sublaminar wire placement is a safe and useful adjunct in the surgical treatment of neurologically intact patients with idiopathic scoliosis.

The anisotropic hydraulic permeability of human lumbar anulus fibrosus. Influence of age, degeneration, direction, and water content

STUDY DESIGN

Experimental investigation to determine the effect of intervertebral disc degeneration on the kinetic behavior of fluid in human anulus fibrosus.

OBJECTIVES

To measure the hydraulic permeability coefficient of anulus fibrosus specimens in the axial, circumferential, and radial directions to determine the anisotropic permeability behavior of nondegenerate and degenerate human intervertebral discs over a range of ages.

SUMMARY OF BACKGROUND DATA

Fluid, a major component of normal intervertebral discs, plays a significant role in their load-supporting mechanisms. Transport of fluid through the intervertebral disc is important for cell nutrition and disc viscoelastic and swelling behaviors. The hydraulic permeability coefficient is the most important material property governing the rate of fluid transport. However, little is known about the anisotropic behavior of this kinetic property and how it is influenced by disc degeneration.

METHODS

Using a permeation testing apparatus developed recently, testing was performed on 306 axial, circumferential, and radial anulus fibrosus specimens from the posterolateral region of 30 human lumbar (L2-L3) discs. A new method, flow-controlled testing protocol, was developed to measure the hydraulic permeability coefficient.

RESULTS

The hydraulic permeability coefficient of anulus fibrosus depended significantly on the disc degenerative grade (P = 0.0001) and flow direction (P = 0.0001). For the nondegenerate group (Grade I), the hydraulic permeability was significantly anisotropic (P < 0.05), with the greatest value in the radial direction (1.924 x 10(-15) m4/Ns) and the lowest value in the circumferential direction (1.147 x 10(-15) m4/Ns). This anisotropic kinetic (flow) behavior of anulus fibrosus varied with disc degeneration. For the Grade III specimen group, there was no significant difference in hydraulic permeability coefficient among the three major directions (P = 0.37). With disc degeneration, the hydraulic permeability coefficient was decreased in the radial direction and increased in the axial and circumferential directions. The variations of hydraulic permeability coefficient from nondegenerate discs (Grade I) to mildly degenerate discs (Grade II) in each direction were significant (P < 0.05). However, the changes in permeability from Grade II to Grade III groups were not significant (P > 0.05) except in the circumferential direction (3.8% increase; P < 0.05).

CONCLUSIONS

The hydraulic permeability of human nondegenerate anulus fibrosus is direction-dependent (i.e., anisotropic), with the greatest permeability in the radial direction. With disc degeneration, the radial permeability of anulus fibrosus decreases, mainly because of decreased water content, and the axial and circumferential permeability coefficients increase, mainly because of structural change, leading to more isotropic permeability behavior for Grade III discs.

Streaming potential of human lumbar anulus fibrosus is anisotropic and affected by disc degeneration

The streaming potential responses of non-degenerate and degenerate human anulus fibrosus were measured in a one-dimensional permeation configuration under static and dynamic loading conditions. The goal of this study was to investigate the influence of the changes in tissue structure and composition on the electrokinetic behavior of intervertebral disc tissues. It was found that the static streaming potential of the anulus fibrosus depended on the degenerative grade of the discs (p = 0.0001) and on the specimen orientation in which the fluid flows (p = 0.0001). For a statically applied pressure of 0.07 MPa, the ratio of streaming potential to applied pressure ranged from 5.3 to 6.9 mV/MPa and was largest for Grade I tissue with axial orientation and lowest for Grade III tissue with circumferential orientation. The dynamic streaming potential responses of anulus fibrosus were sensitive to the degeneration of the disc: the total harmonic distortion factor increased by 108%, from 3.92 +/- 0.66% (mean +/- SD) for Grade I specimens to 8.15 +/- 3.05% for Grades II and III specimens. The alteration of streaming potential reflects the changes in tissue composition and structure with degeneration. To our knowledge, this is the first reported data for the streaming potential of human intervertebral disc tissues. Knowledge of the streaming potential response of the intervertebral disc provides an understanding of potentially important signal transduction mechanisms in the disc and of the etiology of intervertebral disc degeneration.

Degeneration affects the anisotropic and nonlinear behaviors of human anulus fibrosus in compression

Axial and radial specimens of non-degenerate and degenerate human anulus fibrosus (AF) were tested in confined compression to test the hypothesis that degeneration significantly affects the compressive properties of AF. Due to the highly oriented structure of AF, a secondary objective was to investigate anisotropic behaviors of AF in compression. Uniaxial swelling and stress relaxation experiments were performed on site-matched samples of anulus from the anterior outer region of L2-3 intervertebral discs. The experimental stress-relaxation behavior was modeled using the finite deformation biphasic theory and a finite-difference approximation scheme. Significant effects of degeneration but not orientation were detected for the reference stress offset, sigma(offset), and parameters describing the compressive stiffness (i.e. reference aggregate modulus, H(A0), and nonlinear stiffening coefficient, beta). Average values were 0.13+/-0.06 and 0.05+/-0.05 MPa for sigma(offset), 0.56+/-0.21 and 1.10+/-0.53 MPa for H(A0) and 2.13+/-1.48 and 0.44+/-0.61 for beta for all normal and degenerate specimens, respectively. No significant effect of degeneration or orientation were detected for either of the parameters describing the strain-dependent permeability (i.e. reference permeability, k0 and strain-dependent permeability coefficient, M) with average values for all specimens of 0.20+/-0.10 x 10(-15) m4/N-s and 1.18+/-1.30 for k0 and M, respectively. The loss of sigma(offset) was compensated with an elastic stiffening and change in the shape of the equilibrium stress-strain curve with H(A0) for degenerate tissues almost twice that of normal tissues and beta less than one sixth. The increase in reference elastic modulus with degeneration is likely related to an increase in tissue density resulting from the loss of water content. The significant effects of degeneration reported in this study suggested a shift in load carriage from fluid pressurization and swelling pressure to deformation of the solid matrix of the AF. The results also suggest that the highly organized and layered network of the anulus fibrosus, which gives rise to significant anisotropic effects in tension, does not play a major role in contributing to the magnitude of compressive stiffness or the mechanisms of fluid flow of the anulus in the confined compression configuration.

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