Sean A. Salehi

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

OBJECTIVEThe 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). METHODSA 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. RESULTSEleven 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. CONCLUSIONTLIF 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.

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° (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.

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.

Spinal cord compression in beta-thalassemia: case report and review of the literature

Study design: A case report of thoracic spinal cord compression in a 34-year-old male with beta-thalassemia is reported.Objectives: In patients with thalassemia, neurologic complaints should lead to a high index of suspicion for spinal cord compression from marrow expansion, ectopic bone formation and resultant stenosis. Initial presentation, diagnosis, radiographic findings, surgical treatment and follow-up are reviewed.Setting: This case is reported from Chicago, Illinois.Method: A chart review is performed for the purposes of this case report.Results: Patient underwent decompressive laminectomy with good surgical outcome.Conclusion: Rapid diagnosis and treatment of such a condition is essential to optimize the chances of recovery.

Use of internal fiducial markers in frameless stereotactic navigational systems during spinal surgery: Technical note

OBJECTIVEThe use of frameless stereotaxy has expanded the spine surgeon’s ability to perform surgical procedures with instrumentation in areas of narrow anatomic tolerance. In many circumstances, however, it is difficult to register the frameless stereotactic probe using known anatomic landmarks. This occurs typically because landmarks are indistinct, and congenital or surgical defects limit the availability of anatomic fiducials. We propose an accurate and efficient method for registering the frameless stereotactic probe for spinal surgery when a staged procedure is planned. METHODSDuring the first stage of a planned two-stage procedure, a minimum of four cranial fiducial screws are implanted in the posterior element of each vertebra in which stereotactic registration is desired. Stage 1 is completed, and all suture closure is performed. A computed tomographic scan formatted for the frameless stereotactic unit is obtained postoperatively. In the second stage of surgery, registration is performed using cranial screws as internal fiducial markers. RESULTSRegistration is performed easily and quickly using cranial screws as internal fiducial markers. No more than four registration points are necessary to calibrate the system to accuracy within 1.5 mm. CONCLUSIONImplantation of fiducial markers during Stage 1 of a complex staged spinal surgery renders the frameless stereotactic navigational system registration extremely fast and accurate. We advocate the technique to enhance the use of frameless navigational systems for reliable and quick registration of the spine.

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.