Anterior lumbar interbody fusion in comparison with transforaminal lumbar interbody fusion: implications for the restoration of foraminal height, local disc angle, lumbar lordosis, and sagittal balance.

OBJECT: A primary consideration of all spinal fusion procedures is restoration of normal anatomy, including disc height, lumbar lordosis, foraminal decompression, and sagittal balance. To the authors' knowledge, there has been no direct comparison of anterior lumbar interbody fusion (ALIF) with transforaminal lumbar interbody fusion (TLIF) concerning their capacity to alter those parameters. The authors conducted a retrospective radiographic analysis directly comparing ALIF with TLIF in their capacity to alter foraminal height, local disc angle, and lumbar lordosis. METHODS: The medical records and radiographs of 32 patients undergoing ALIF and 25 patients undergoing TLIF from between 2000 and 2004 were retrospectively reviewed. Clinical data and radiographic measurements, including preoperative and postoperative foraminal height, local disc angle, and lumbar lordosis, were obtained. Statistical analyses included mean values, 95% confidence intervals, and intraobserver/interobserver reliability for the measurements that were performed. RESULTS: Our results indicate that ALIF is superior to TLIF in its capacity to restore foraminal height, local disc angle, and lumbar lordosis. The ALIF procedure increased foraminal height by 18.5%, whereas TLIF decreased it by 0.4%. In addition, ALIF increased the local disc angle by 8.3 degrees and lumbar lordosis by 6.2 degrees, whereas TLIF decreased the local disc angle by 0.1 degree and lumbar lordosis by 2.1 degrees. CONCLUSIONS: The ALIF procedure is superior to TLIF in its capacity to restore foraminal height, local disc angle, and lumbar lordosis. The improved radiographic outcomes may be an indication of improved sagittal balance correction, which may lead to better long-term outcomes as shown by other studies. Our data, however, demonstrated no difference in clinical outcome between the two groups at the 2-year follow-up.

Mathematical calculation of pedicle subtraction osteotomy size to allow precision correction of fixed sagittal deformity.

STUDY DESIGN: This is a retrospective review of 15 consecutive fixed sagittal plane deformity patients who have undergone pedicle subtraction osteotomies. The focus of this article is the application of a trigonometric equation that calculates the degree of correction needed to achieve sagittal balance. The intraoperative predictive accuracy and clinical radiographic results of using this mathematical equation are discussed. OBJECTIVE: The need for a precise and reproducible planning tool for the correction of sagittal imbalance prompted us to apply a simple trigonometric equation to achieve the desired sagittal alignment of the spine. SUMMARY OF BACKGROUND DATA: Establishing sagittal balance has been widely recognized as one of the most important parameters in optimizing outcomes for spinal reconstruction patients. Preoperative planning for sagittal plane correction in adult spinal deformity has traditionally been done by estimation or with cumbersome film cutouts. To our knowledge, there has not been a consistent method of calculating the exact number of degrees needed to reestablish spinal balance. METHODS: Patients' C7 plumb lines are measured on a 36-inch radiograph to assess the degree of sagittal imbalance and determine how many degrees of correction (and subsequent millimeters of wedge resection) are needed. Applying a basic trigonometric formula for the tangent to the sagittal alignment is used to do this. RESULTS: We have used this technique reliably in a series of 15 consecutive patients to reestablish sagittal balance. The predicted degree of correction was compared to the achieved degree of correction at the site of the osteotomy. This comparison was accurate to within 3 degrees (the standard error of measurement for the method of Cobb) in all cases except 2. CONCLUSIONS: By using a simple mathematical equation, one can reliably determine the degree of pedicle subtraction osteotomy needed for correction of sagittal deformity. This technique is reproducible and has led to successful clinical outcomes.

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.

Salvage technique of posterior iliac bolt placement in long-segment spinal constructs with a previous posterior iliac crest harvest: technical note.

OBJECTIVE AND IMPORTANCE: Fusion between the lumbar spine and sacrum has been used to treat deformity, degenerative disease, trauma, and tumor. These constructs have a higher failure rate when a long construct is designed, in patients with poor bone quality, and in patients with previous irradiation or with significant osteoporosis. CLINICAL PRESENTATION: Extending the construct to the pelvis has been shown to increase the fusion rate of these patients and to reduce the risk of hardware failure before fusion has occurred. INTERVENTION: We extend the constructs with the use of iliac bolts placed within the posterior iliac crests. Placement of these bolts can be challenging after the posterior iliac crest has been harvested for autologous bone in a previous operation. CONCLUSION: The purpose of this technical note is to describe our salvage technique of iliac bolt placement as an adjunct to lumbar-sacral fusions in a previously harvested iliac crest.

Adjuvant gamma knife stereotactic radiosurgery at the time of tumor progression potentially improves survival for patients with glioblastoma multiforme.

OBJECTIVE: Gamma knife stereotactic radiosurgery (GK-SRS) is a safe and noninvasive treatment used as adjuvant therapy for patients with glioblastoma multiforme (GBM). Several studies have yielded conflicting results in the effectiveness of radiosurgery in GBM. This study is a retrospective review of our institutional experience with GK-SRS adjuvant therapy in the treatment of GBM. METHODS: From October 1998 to January 2003, 51 consecutive patients were treated with GK-SRS as an "upfront" adjuvant therapy after surgery or at the time of tumor progression at Northwestern Memorial Hospital. Survival analysis was performed using the Kaplan-Meier actuarial method. Univariate and multivariate analyses of patient characteristics and treatment variables were performed. RESULTS: Treatment with adjuvant GK-SRS yielded a median overall survival of 14.3 months for our cohort. Survival rate of the cohort was 68% at 12 months, 30% at 24 months, and 24% at 36 months. Karnofsky performance score greater than 90 and adjuvant chemotherapy were associated with increased survival on multivariate analysis. Adjuvant GK-SRS performed at tumor progression seems to increase median survival to 16.7 months compared with 10 months when performed after the time of initial tumor resection. Median survival rates by recursive partitioning analysis class breakdown in our cohort are greater than those predicted by other studies. CONCLUSION: GK-SRS is a relatively safe and noninvasive procedure that conferred an improvement in overall survival of GBM patients in our retrospective study. Particularly, GK-SRS may improve overall survival when performed at the time of tumor progression.

Advances in surgical management of malignancies of the cranial base: the extended transbasal approach.

The extended transbasal approach combines a bifrontal craniotomy with an orbital nasal and potentially a sphenoethmoidal osteotomy to provide excellent access to malignancies of the anterior, middle and posterior skull base. The approach enables the en bloc resection of tumors within the frontal lobes, orbits, paranasal sinuses and sphenoclival corridors without brain retraction and may obviate the need for transfacial access. We present our 7-year experience during which 29 patients underwent surgery with the extended transbasal exposure. In 25 patients the extended transbasal approach was used alone; in the remaining four it was combined with additional approaches. With exception of two patients, all lesions were removed en bloc. Reconstruction was accomplished with the use of pericranium and in some instances a temporalis muscle pedicle or a gracilis microvascular free flap. There were no mortalities associated with this approach. Seven patients experienced infections, four patients experienced cerebral spinal fluid (CSF) leakage, two patients who had received adjuvant radiation experienced scalp necrosis, three patients experienced pneumocephalus, and 29 patients experienced cranial neuropathies, the majority of which were loss of olfaction. The average follow-up for our patients was 34 months with a range of 2--62 months.

Rapid wireless transmission of head CT images to a personal digital assistant for remote consultation.

RATIONALE AND OBJECTIVES: We describe a simple technique for transmission of a complete set of cranial computed tomography (CT) images to a commercially available wireless personal digital assistant (PDA) for remote teleradiology consultation. MATERIALS AND METHODS: A complete set of images from the head CT of a trauma patient with subdural hematoma (19 images) was captured from a picture archiving and communication system and transmitted wirelessly as an e-mail attachment after being compressed. The images were retrieved, decompressed, and reviewed using commercially available software and a PDA with cellular phone capability. RESULTS: A complete head CT was transmitted to a remote radiologist's wireless PDA for consultation. The entire procedure (including image capture, transmission, and review) took approximately 11.5 minutes. CONCLUSION: Using the technique described in this article the wireless PDA may function as a robust medium for facilitating care of brain trauma patients by allowing rapid access to trauma radiologists or neurosurgeons.

Anterior atlas fracture following suboccipital decompression for Chiari I malformation. Report of two cases.

Chiari I malformation, a congenital disorder involving downward displacement of the cerebellar tonsils through the foramen magnum, is often treated surgically by performing suboccipital craniectomy and C-1 laminectomy. The authors report two cases in which fracture of the anterior atlantal arch occurred during the postoperative period following Chiari I decompression and C-1 laminectomy causing significant neck pain. The findings indicate that interruption of the integrity of the posterior arch of C-1, iatrogenically or otherwise, confers increased risk of anterior arch fracture. A C-1 fracture should therefore be considered in the differential diagnosis of posterior cervical pain in patients who have previously undergone decompression for Chiari I malformation.

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.

Superficial temporal artery pseudoaneurysm: diagnosis and preoperative planning with CT angiography.

We report the use of CT angiography in the diagnosis and preoperative planning of a superficial temporal artery pseudoaneurysm. A 50-year-old man presented with a pulsatile preauricular mass 4 weeks after undergoing pterional craniotomy for aneurysm repair. CT angiography revealed a 2.5-cm pseudoaneurysm arising from the posterior margin of the right superficial temporal artery at the inferior margin of the craniotomy incision. To our knowledge, this is the first reported case showing the usefulness of CT angiography alone in the diagnosis and characterization of a superficial temporal artery pseudoaneurysm.

Lumbosacropelvic junction reconstruction resulting in early ambulation for patients with lumbosacral neoplasms or osteomyelitis.

Lumbosacropelvic junction instability may result from a variety of disease processes including primary and metastatic sacral tumors and degenerative disease. Regardless of the origin of the disease, restoring or maintaining spinal stability at this junction is essential for normal translation of axial forces from the lumbar spine and sacrum to the pelvis. Spinal stability is also critical for maintaining structural integrity, preventing neurological function deterioration, and alleviating resultant mechanical or axial pain. In this report, the authors describe one option for safe and effective spinal pelvic stabilization by using a transiliac rod and iliac bolt construct, which results in early postoperative ambulation, preserved neurological function, and reduced axial pain in selected patients.

Selective cerebral revascularization as an adjunct in the treatment of giant anterior circulation aneurysms.

Cerebral revascularization, an indispensable component of neurovascular surgery, has been performed in the treatment of cranial base tumors, complex cerebral aneurysms, and occlusive cerebrovascular disease. The goal of a revascularization procedure is to augment blood flow distally. It can therefore be used as an adjunctive measure in the treatment of complex neurosurgical disease processes that require parent artery sacrifice for definitive treatment. In the treatment of giant anterior circulation aneurysms, for instance, a cerebral revascularization procedure may be considered in patients in whom the collateral circulation is marginal and in whom lesions may be treated either using a Hunterian-based strategy or clip-assisted reconstruction requiring a prolonged period of temporary occlusion. To date, there is no entirely effective method known to produce long-term tolerance to carotid artery (CA) sacrifice and, largely for that reason, some neurovascular surgeons advocate universal revascularization. The authors of this report, however, prefer to perform revascularization only in the limited subset of patients in whom preoperative assessment has revealed risk factors for cerebral ischemia due to hypoperfusion. In this paper, the authors introduce their protocol for assessing cerebrovascular reserve capacity, indications for cerebral revascularization in the treatment of complex anterior circulation aneurysms, and discuss their rationale for choosing to practice selective, rather than universal, revascularization.

Evaluation of personal digital assistants as an interpretation medium for computed tomography of patients with intracranial injury.

The objective of the study was to assess the feasibility of using a personal digital assistant (PDA) as a medium for the interpretation of cranial CT scans of trauma patients. Twenty-one noncontrast cranial CT scans were transferred in their entirety to a PDA from the picture archiving and communications system (PACS) utilizing General Electric (GE) PathSpeed PACS Web Server interface and synchronization. All CT scans had been interpreted by board-certified radiologists prior to the study. Seven of the scans demonstrated subarachnoid hemorrhage, seven demonstrated subdural hematomas, and the remaining scans were normal. After transfer to the PDA, all images were separately reviewed in a blinded manner by a radiologist and a neurosurgeon. Images were graded for their quality and diagnostic utility in the evaluation of intracranial hemorrhage. Image quality was categorized as excellent, very good, acceptable for diagnosis, or not acceptable for diagnosis. Based on the radiologic diagnosis, recommendation for surgical management was made by the reviewing neurosurgeon. The accuracy rate for both the radiologist and the neurosurgeon in the detection of intracranial hemorrhage was 95%. There was one false negative which was attributed to error in judgment rather than poor image quality. This diagnostic error did not affect patient management. The sensitivity and specificity for detection of intracranial hemorrhage were 93% and 100%, respectively. Image quality was judged to be excellent in 90% of the cases and very good in the remaining 10%. Our results suggest that the PDA is a robust medium for interpretation of CT scans in patients with suspected hemorrhage following intracranial injury. In this setting, the PDA should be considered for teleradiology purposes.

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.