Posterior vertebral column subtraction osteotomy for the treatment of tethered cord syndrome: review of the literature and clinical outcomes of all cases reported to date.

Tethered cord syndrome (TCS) is a debilitating condition of progressive neurological decline caused by pathological, longitudinal traction on the spinal cord. Surgical detethering of the involved neural structures is the classic method of treatment for lumbosacral TCS, although symptomatic retethering has been reported in 5%-50% of patients following initial release. Subsequent operations in patients with complex lumbosacral dysraphic lesions are fraught with difficulty, and improvements in neurological function are modest while the risk of complications is high. In 1995, Kokubun described an alternative spine-shortening procedure for the management of TCS. Conducted via a single posterior approach, the operation relies on spinal column shortening to relieve indirectly the tension placed on the tethered neural elements. In a cadaveric model of TCS, Grande and colleagues further demonstrated that a 15-25-mm thoracolumbar subtraction osteotomy effectively reduces spinal cord, lumbosacral nerve root, and filum terminale tension. Despite its theoretical appeal, only 18 reports of the use of posterior vertebral column subtraction osteotomy for TCS treatment have been published since its original description. In this review, the authors analyze the relevant clinical characteristics, operative data, and postoperative outcomes of all 18 reported cases and review the role of posterior vertebral column subtraction osteotomy in the surgical management of primary and recurrent TCS.

Abdominal complications following kyphosis correction in ankylosing spondylitis.

Spinal deformity surgery is associated with high rates of morbidity and a wide range of complications. The most significant abdominal complications following kyphosis correction, while uncommon, can certainly pose significant infectious and hemodynamic risks to the patient. Abdominal compartment syndrome is the most severe of the sequelae. It is the end result of elevated abdominal compartment pressure with physiological compromise and end organ system dysfunction. Although most commonly associated with trauma, abdominal compartment syndrome has also been witnessed following massive fluid shifts, which can occur during adult spinal deformity surgery. In this manuscript, we report on 2 patients with ankylosing spondylitis who developed significant abdominal pathology requiring exploratory laparotomy following kyphosis correction. In addition to describing the details of each case, we propose explanations of the relevant pathophysiology and review diagnostic and treatment strategies for such events. The key to effectively treating such a debilitating complication is to recognize it quickly and intervene rapidly and aggressively.

Posterior vertebral column subtraction osteotomy: a novel surgical approach for the treatment of multiple recurrences of tethered cord syndrome.

Recurrent tethered cord syndrome (TCS) has been reported to develop in 5-50% of patients following initial spinal cord detethering operations. Surgery for multiple recurrences of TCS can be difficult and is associated with significant complications. Using a cadaveric tethered spinal cord model, Grande and colleagues demonstrated that shortening of the vertebral column by performing a 15-25-mm thoracolumbar osteotomy significantly reduced spinal cord, lumbosacral nerve root, and terminal filum tension. Based on this cadaveric study, spinal column shortening by a thoracolumbar subtraction osteotomy may be a viable alternative treatment to traditional surgical detethering for multiple recurrences of TCS. In this article, the authors describe the use of posterior vertebral column subtraction osteotomy (PVCSO) for the treatment of 2 patients with multiple recurrences of TCS. Vertebral column resection osteotomy has been widely used in the surgical correction of fixed spinal deformity. The PVCSO is a novel surgical treatment for multiple recurrences of TCS. In such cases, PVCSO may allow surgeons to avoid neural injury by obviating the need for dissection through previously operated sites and may reduce complications related to CSF leakage. The novel use of PVCSO for recurrent TCS is discussed in this report, including surgical considerations and techniques in performing PVCSO.

Endovascular embolization of a recurrent cervical giant cell neoplasm using N-butyl 2-cyanoacrylate.

Pre-operative endovascular embolization of spinal giant cell tumors (GCTs) has been an effective strategy to reduce blood loss during surgical resection. Traditionally, spinal GCTs have been embolized with polyvinyl acetate (PVA) particles. We present the pre-operative embolization of a recurrent cervical GCT with N-butyl 2-cyanoacrylate (NBCA) rather than PVA. The patient was a 17-year-old female who, 3 months prior, had undergone a surgical resection of a cervical GCT without pre-operative embolization. She returned with tumor recurrence in the approximate location. Resection was recommended, and pre-operative embolization was requested. The tumor was embolized with NBCA. Post-embolization angiography demonstrated significantly decreased tumor "blush" and a significant reduction of the vascular supply. This is the first reported use of NBCA for the pre-operative embolization of a cervical GCT. The benefits of NBCA over PVA particles include superior penetration, permanent tumor embolization and lower exposure to radiation due to shorter procedure time.

A novel mathematical model of the sagittal spine: application to pedicle subtraction osteotomy for correction of fixed sagittal deformity.

BACKGROUND CONTEXT: The C7 plumb line method oversimplifies the true complexity of the spine. In a previous study, we mathematically modeled the normal spine using the spline function, enabling quantification of previously undescribed measurements such as area under the curve (AUC) and average sagittal position. The spine in fixed sagittal imbalance and the results of surgical correction have not been studied in a similar manner. PURPOSE: To quantitatively evaluate changes in spinal conformation in patients who underwent pedicle subtraction osteotomy (PSO) using measures derived from the spline model and to correlate these changes with functional outcome. STUDY DESIGN: Application of a mathematical model to a cohort of patients who underwent deformity surgery. PATIENT SAMPLE: Thirty-four consecutive patients with fixed sagittal imbalance who underwent PSO from 2001 to 2003. OUTCOME MEASURES: Preoperative and postoperative 22-item Scoliosis Research Society (SRS-22) Outcomes Questionnaire scores were used for functional assessment. METHODS: Radiographs of the 34 patients who underwent thoracic or lumbar PSO with at least 2 years of follow-up were examined at three time points. The posterosuperior aspect of each vertebral body was chosen as a representative point for the spinal sagittal curve. A cubic spline function was derived from these points. From this function, the AUCs and average sagittal positions of the thoracic, lumbar, and thoracolumbar segments were calculated. RESULTS: The average sagittal position does not overlap the C7 plumb line in deformity patients, but is a much more stable measure. In the lumbar PSO cohort, the lumbar AUC and average sagittal position were not significantly different among normal, preoperative, and postoperative groups. The thoracic and thoracolumbar AUCs and average sagittal positions were dramatically more positive in the preoperative cohort compared with normals; these values significantly decreased toward neutrality after lumbar PSO, but remained abnormal. In the thoracic PSO cohort, the lumbar, thoracic, and thoracolumbar AUCs and average sagittal positions were not significantly different among normal, preoperative, and postoperative groups. The changes in thoracolumbar AUC and average sagittal position were better predictors of the SRS-22 total score than the change in C7 plumb line. CONCLUSIONS: The average sagittal position more comprehensively captures the nuances of a nonlinear spinal curve. Subcurve analysis enabled by the spline model is particularly helpful in assessing deformity and surgical correction on a segmental level. Increased sensitivity to the nuances of the spinal curve in this model results in superior correlation with clinical outcomes when compared with the C7 plumb line. We feel that a critical examination of the spinal curve will lead to improved understanding of deformity and planning for an optimal correction.

Maximizing the potential of minimally invasive spine surgery in complex spinal disorders.

Minimally invasive surgery (MIS) in the spine was primarily developed to reduce approach-related morbidity and to improve clinical outcomes compared with those following conventional open spine surgery. Over the past several years, minimally invasive spinal procedures have gained recognition and their utilization has increased. In particular, MIS is now routinely used in the treatment of degenerative spine disorders and has been shown to be as effective as conventional open spine surgeries. Although the procedures are not yet widely recognized in the context of complex spine surgery, the true potential in minimizing approach-related morbidity is far greater in the treatment of complex spinal diseases such as spinal trauma, spinal deformities, and spinal oncology. Conventional open spine surgeries for complex spinal disorders are often associated with significant soft tissue disruption, blood loss, prolonged recovery time, and postsurgical pain. In this article the authors review numerous cases of complex spine disorders managed with MIS techniques and discuss the current and future implications of these approaches for complex spinal pathologies.

Neutral upright sagittal spinal alignment from the occiput to the pelvis in asymptomatic adults: a review and resynthesis of the literature.

OBJECT: An increasing emphasis is being placed on the preservation or restoration of neutral upright sagittal spinal alignment in both deformity surgery and routine spinal operations. Sagittal spinal alignment is becoming recognized as an important predictor of a patient's outcome after spinal surgery. In this literature review, the authors analyze data obtained from previously published studies conducted to evaluate neutral upright sagittal spinal alignment from the occiput to the pelvis in asymptomatic adults. METHODS: A review of the English-language literature was conducted to identify studies conducted to evaluate neutral upright sagittal spinal (occiput-pelvis) alignment in asymptomatic adult volunteers with no spinal disease. The authors identified 12 articles that met the strict primary inclusion criteria of the current study. From these articles, 23 angles and displacements were selected to depict neutral upright sagittal occiput-pelvis alignment. Pooled estimates of the mean and variance were calculated for angles and displacements that met secondary inclusion criteria. The greatest variation in the regional spinal curves occurred in the cervical spine from C-2 to C-7, whereas the greatest focal angulation in the spine occurred from L-4 to S-1. Sagittal spinal balance was maintained in a narrow range for alignment of the spine over the pelvis and femoral heads. CONCLUSIONS: Neutral upright sagittal occiput-pelvis alignment in asymptomatic adults has been well studied regionally. Despite a wide variation in the undulating lordotic and kyphotic regional curves from the occiput to the pelvis, sagittal spinal balance is maintained in a narrower range for alignment of the spine over the pelvis and femoral heads.

A novel approach to sagittal balance restoration following iatrogenic sacral fracture and resulting sacral kyphotic deformity. Technical note.

The authors describe the use of sacral pedicle subtraction osteotomy (PSO) with multiple sacral alar osteotomies for the correction of sacral kyphosis and pelvic incidence and for achieving sagittal balance correction in cases of fixed sagittal deformity after a sacral fracture. In this paper, the authors report on a novel technique using a series of sacral osteotomies and a sacral PSO to correct a fixed sagittal deformity in a patient with a sacral fracture that had healed in a kyphotic position. The patient sustained this fracture after a previous surgery for multilevel instrumented fusion. Preoperative and postoperative radiographic studies are reviewed and the clinical course and outcome are presented. Experts agree that the pelvic incidence is a fixed parameter that dictates the morphological characteristics of the pelvis and affects spinopelvic orientation and sagittal spinal alignment. An increased pelvic incidence is associated with a higher degree of spondylolisthesis in the lumbosacral junction, and increased shear forces across this junction. The authors demonstrate that the pelvic incidence can be altered and corrected with a series of sacral osteotomies to improve sacral kyphosis, compensatory lumbar hyperlordosis, and sagittal balance.

Revision deformity surgery.

Revision deformity surgery may be necessary for several reasons. Symptomatic pseudarthrosis, implant failure or pull-out, or loss of correction may mandate reoperation. The keys to a successful revision procedure are a careful analysis of the problem, particularly the mode of failure and the contributing biomechanical factors, and the development of an appropriate surgical plan.

Clinical and radiographic outcomes of thoracic and lumbar pedicle subtraction osteotomy for fixed sagittal imbalance.

OBJECT: The authors conducted a study to evaluate the radiographically documented and functional outcomes obtained in patients who underwent pedicle subtraction osteotomy (PSO). They also compared outcomes after classification of cases into thoracic and lumbar PSO subgroups. METHODS: The authors analyzed data obtained in 35 consecutive PSO-treated patients with sagittal imbalance. One surgeon performed all surgeries. The minimal follow-up period was 2 years. Events during the perioperative course and complications were noted. Standing long-film radiographs of the spine were obtained and measurements were made preoperatively, immediately postoperatively, and at most recent follow-up examination. The modified Prolo Scale and the 22-item Scoliosis Research Society (SRS-22) Outcomes Questionnaire were administered. Early complications after PSO included neurological injury, wound-related problems, and nosocomial infections. Late complications were limited to pseudarthrosis and attendant instrumentation failure. Early and late complication rates ranged from 10 to 30% for both thoracic and lumbar PSO cohorts. Lumbar PSO was associated with improvements in local, segmental, and global measures of sagittal balance, whereas thoracic PSO was only associated with local improvement. Most patients rated their functional status as fair to good according to the modified Prolo Scale and reported, according to the SRS-22 Outcomes Questionnaire, that they were satisfied with the overall treatment of their back condition. CONCLUSIONS: The ability to perform a PSO at both lumbar and thoracic levels is a powerful asset for the spine surgeon treating spinal deformity. In the present study radiographic and clinical outcomes were superior when PSO was used to treat lumbar deformity rather than thoracic deformity because of several anatomical and technical obstacles that hindered the thoracic procedure. Nevertheless, the thoracic PSO proved a useful addition with which to produce regional improvement in sagittal balance for patients with a fixed thoracic kyphosis.

Transforaminal lumbar interbody fusion: surgical technique and results in 24 patients.

OBJECTIVE: The advantage of anterior column support and fusion in addition to pedicle fixation in patients with degenerative spinal disorders has become increasingly clear. With the increase in popularity of this treatment, a variety of techniques have been used to achieve the goal of anterior column support, fusion, and segmental instrumentation. Posterior lumbar interbody fusion has been used since the late 1940s in the treatment of degenerative lumbar spine. We evaluated a modification to posterior lumbar interbody fusion called transforaminal lumbar interbody fusion (TLIF). METHODS: A retrospective analysis was performed on 24 patients (9 women, 15 men) who underwent TLIF. The approach involved a unilateral laminectomy and inferior facetectomy at the level of fusion. The interbody fusion was achieved from this unilateral approach by performing discectomy, arthrodesis, and insertion of one or two titanium cages packed with autologous bone. The average age of the patients in this study was 42.6 +/- 12.5 years. Five patients were smokers. Five cases were related to workmen's compensation. Seventeen patients' original symptoms were a combination of low back pain and radiculopathy. Ten patients had had a previous spine operation. RESULTS: Eleven patients had L4-S1 TLIFs. The rest of the patients had a single-level TLIF (L2-S1). Average intensive care unit and floor days were 1.1 +/- 1.0 and 5.8 +/- 2.2 days, respectively. The number of days to ambulation was 2.8 +/- 1.6 days. There were a total of six self-limited complications in 24 patients (including one transient neurological complication). The average follow-up time was 16.9 +/- 9.1 months. Twenty-two patients had solid fusions. A modified Prolo scale (4 worst, 20 best) was used to evaluate the clinical outcome. The average score was 16.1 +/- 4.1. CONCLUSION: TLIF is a reliable and safe technique for interbody support that can be performed with excellent clinical outcome. In the authors' experience, TLIF offers excellent exposure with minimal risk. This applies particularly in cases of repeat spine surgery, in which the presence of scar tissue makes traditional posterior lumbar interbody fusion techniques difficult or impossible. In addition, TLIF seems to be a viable alternative to anteroposterior circumferential fusion and/or anterior lumbar interbody fusion.

Is laparoscopic anterior lumbar interbody fusion a useful minimally invasive procedure?

OBJECTIVE: Laparoscopic anterior lumbar interbody fusion (LALIF) has been demonstrated to be safe and effective. Its use as a standard surgical technique has been recommended for arthrodesis in the lumbosacral region. We reviewed our experience with LALIF for safety, effectiveness, and usefulness. METHODS: Retrospective review of 14 patients who underwent LALIF was performed. All patients had a diagnosis of degenerative disc disease with medically retractable mechanical back pain. RESULTS: No intraoperative vascular or neurological injury was encountered. An average operating time of 300 minutes with blood loss of 60 ml was found. The average hospital stay was 3.4 days. At 3 to 6 months after surgery, 80% fusion rates were achieved. CONCLUSION: Although LALIF is a safe and effective procedure, it has many disadvantages, which make it a less than optimal procedure for routine use. Other minimally invasive approaches to the anterior lumbar spine result in similar beneficial results without the drawbacks associated with LALIF.

Neural function preservation and early mobilization after resection of metastatic sacral tumors and lumbosacropelvic junction reconstruction. Report of three cases.

The management of tumors that metastasize to the sacrum remains controversial. Typically, resection of such tumors and reconstruction of the lumbopelvic junction requires sacrifice of neural elements resulting in neurological dysfunction and prolonged periods of bed rest. This severely affects the quality of life in patients in whom there is frequently a limited life expectancy. The authors describe three patients who underwent subtotal resection of metastatic sacral tumors. Postoperatively, good outcome was demonstrated in all patients. The authors present a technique for debulking and reconstruction that provides immediate spinopelvic junction stability and allows for early mobilization. Quality of life is significantly improved compared with that resulting from either medical treatment or traditional surgery.

Improved repair of cervical esophageal fistula complicating anterior spinal fusion: free omental flap compared with pectoralis major flap. Report of four cases.

Esophageal injury is a serious complication of anterior cervical fusion. A team approach to the management of these cases is described. The authors performed spinal assessment, control of the fistula, and interposition of a vascularized flap between the spine and the esophagus. They compared the overall efficacy of the pectoralis major flap (pedicled; two cases) and omental flap (free; two cases).

Revision strategies for lumbar pseudarthrosis.

Management and avoidance of lumbar pseudarthrosis are among the most common and challenging tasks faced by reconstructive spine surgeons. The risks of pseudarthrosis can be broadly divided into two categories: those within a surgeon's control and those not within his/her control. These include biological factors, graft choices, site preparation, and surgical design. The authors review the biological factors that affect fusion and how they can be manipulated to avoid or manage lumbar pseudarthrosis. Surgical planning and construct design to prevent or treat pseudarthrosis will also be discussed. Additionally, the importance of restoring sagittal balance will be reviewed.

Management of iatrogenic flat-back syndrome.

Iatrogenic loss of lordosis is now frequently recognized as a complication following placement of thoracolumbar instrumentation, especially with distraction instrumentation. Flat-back syndrome is characterized by forward inclination of the trunk, inability to stand upright, and back pain. Evaluation of the deformity should include a full-length lateral radiograph obtained with the patient's knees and hips fully extended. The most common cause of the deformity includes the use of distraction instrumentation in the lumbar spine and pseudarthrosis. Surgical treatment described in the literature includes opening (Smith-Petersen) osteotomy, polysegmental osteotomy, and closing wedge osteotomy. The authors will review the literature, cause, clinical presentation, prevention, and surgical management of flat-back syndrome.

Prophylactic placement of an inferior vena cava filter in high-risk patients undergoing spinal reconstruction.

OBJECT: The purpose of this study was to evaluate the safety and efficacy of prophylactic inferior vena cava (IVC) filter placement in high-risk patients who undergo major spine reconstruction. METHODS: In the pilot study, 22 patients undergoing major spine reconstruction received prophylactic IVC filters. These patients were prospectively followed to evaluate complications related to the filter, the rate of deep venous thrombosis (DVT) formation, and the rate of pulmonary embolism (PE). These data were compared with those obtained in a retrospective review for PE in a matched cohort treated at the same institution. At a second institution the treatment guidelines were implemented in 17 patients undergoing complex spine surgery with the same follow-up criteria. In the pilot study, no patient experienced PE (0%), whereas two had DVT (9%). Bilateral DVT developed postoperatively in one patient (associated morbidity rate 4.5%), who required thrombolytic therapy. One patient died of unrelated surgical complications. The PE rate in the matched cohort at the same institution was 12%. At the second institution, no patient had PE, and no complications were noted. CONCLUSIONS: In this patient population, prophylactic IVC filter placement appears to decrease the PE rate substantially, from 12 to 0%. The placement of IVC filters appears to be a safe and efficacious intervention for prevention of PE in high-risk patients.

Surgical strategies for vertebral osteomyelitis and epidural abscess.

Pyogenic vertebral discitis and osteomyelitis (PVDO) has become an increasing problem for the spine surgeon. Despite recent advances in medical care and improved diagnostic neuroimaging, PVDO remains a major cause of illness and death in the elderly population. Infection of the spinal column often presents insidiously; however, if not treated appropriately and in a timely manner it can lead to severe neurological impairment, systemic septicemia, and progressive spinal deformity. In this paper the authors review the epidemiological and pathophysiological features and the clinical presentation of PVDO. Conventional medical therapy is described, with a particular focus on the methods of diagnosis. Surgical strategies for PVDO are then presented based on the literature and according to the practice of the senior author (S.L.O.), with an emphasis placed on structural considerations, implant selection, and techniques for augmenting vascular tissue to the site of infection.

Thoracic pedicle screw fixation for spinal deformity.

Techniques to improve segmental fixation have advanced the ability to correct complex spinal deformity. The purpose of instrumentation is to correct spinal deformity or to stabilize the spine to enhance the long-term biological fusion. The ultimate goal of spinal deformity surgery is the creation of a stable, balanced, pain-free spine centered over the pelvis in the coronal and sagittal planes. The minimum number of segments should be fused. These concepts remain challenging in the setting of deformity and instability. Successful results can be obtained if the surgeon understands the technology available, its capabilities, biological limitations, and the desired solution. The authors prefer to use thoracic pedicle screws when treating patients with spinal deformity because they provide greater corrective forces for realignment. This allows shorter-segment constructs and the possibility of true derotation in correction. In this article the authors focus on the use of thoracic transpedicular screw fixation in the management of complex spinal disorders and deformity.

Benign sacral tumors.

Primary tumors of the sacrum are rare. In adults, the most common sacral tumors are metastases. The most common primary sacral tumor is a chordoma. Chordomas along as well as tumors such as chondrosarcomas, osteosarcomas, myxopapillary ependymomas, myelomas, and Ewing sarcomas are considered malignant. In this article the authors focus on benign sacral tumors.