The surgical technique of minimally invasive transforaminal lumbar interbody fusion.

We aim to describe the minimally invasive transforaminal lumbar interbody fusion (MI-TLIF) technique. The MI-TLIF procedure was developed to achieve the same goal of neural decompression and interbody arthrodesis as the traditional, open TLIF techniques. MI-TLIF has been utilized in the treatment of an array of lumbar pathologies, while offering the advantages of reducing soft tissue trauma, decreasing postoperative pain, and reducing the rate of complication when compared to the open techniques. The surgical technique of MI-TLIF is described in a step-by-step fassion. A technical review of this novel minimally invasive procedure was performed. Additionally, data collected through our experience with this procedure is reported. Data was collected retrospectively from patients between January 2008 and December 2009 who underwent MI-TLIF. The mean preoperative VAS score was 6.12±2.02 compared to 2.11±2.69 postoperatively. The mean ODI score dropped from 38.29±13.19 preoperatively to 16.00 ±16.598 postoperatively. Eighty-four patients who underwent MI-TLIF between October 2007 and December 2010 were divided based on age (over or under 65 years) and intraoperative estimated blood loss (EBL) was compared. The mean EBL for the young age group was 93.37±102.16 mL compared to 100 ±61.24 mL for the older group. Operation times for the MI-TLIF procedure has decreased from 3-4 hours to approximately 2 hours throughout our experience with this technique. The MI-TLIF technique is a safe and effective procedure offering the advantages of less tissue damage, less blood loss, and reduced postoperative hospitalization over the open techniques.

Minimally invasive approach for far lateral disc herniations: results from 20 patients.

BACKGROUND: Far lateral lumbar disc herniations, while infrequent, are a substantial cause of morbidity causing painful radicular syndromes often accompanied by a motor or sensory deficit. Surgical treatment can be challenging technically because of unfamiliar lateral anatomy and the importance of adjacent osseous structures, notably the pars interarticularis and facet joint. METHOD: The traditional approach for a far lateral lumbar disc herniation involves a midline incision, wide lateral subperiosteal exposure and partial removal of these structures with the potential for iatrogenic instability. A paramedian approach to the lateral compartment of the disc space is advantageous because it directly targets the pathology. The use of recently developed minimally invasive retractor systems decreases tissue dissection and blood loss and improves postoperative recovery. RESULTS AND DISCUSSION: We present a series of 20 patients who underwent far lateral discectomy using a minimally invasive muscle splitting approach.

Feasibility and safety of neural tissue transplantation in patients with syringomyelia.

Transplantation of fetal spinal cord (FSC) tissue has demonstrated significant potential in animal models for achieving partial anatomical and functional restoration following spinal cord injury (SCI). To determine whether this strategy can eventually be translated to humans with SCI, a pilot safety and feasibility study was initiated in patients with progressive posttraumatic syringomyelia (PPTS). A total of eight patients with PPTS have been enrolled to date, and this report presents findings for the first two patients through 18 months postoperative. The study design included detailed assessments of each subject at multiple pre- and postoperative time points. Outcome data were then compared with each subject's own baseline. The surgical protocol included detethering, cyst drainage, and implantation of 6-9-week postconception human FSC tissue. Immunosuppression with cyclosporine was initiated a few days prior to surgery and continued for 6 months postoperatively. Key outcome measures included: serial magnetic resonance imaging (MRI) exams, standardized measures of neurological impairment and functional disability, detailed pain assessment, and extensive neurophysiological testing. Through 18 months, the first two patients have been stable neurologically and the MRIs have shown evidence of solid tissue at the graft sites, without evidence of donor tissue overgrowth. Although it is still too soon to draw any firm conclusions, the findings from the initial two patients in this study suggest that intraspinal grafting of human FSC tissue is both feasible and safe.

Neurophysiological assessment of the feasibility and safety of neural tissue transplantation in patients with syringomyelia.

The feasibility and safety of a procedure involving fetal spinal cord tissue transplantation in patients with syringomyelia was assessed using a neurophysiological protocol designed to quantitate peripheral nerve function, spinal cord reflex excitability, and spinal cord conduction pathways essential for somatosensory evoked potentials. We report here data obtained before and for 18 months following the transplantation procedure performed on the first two patients in this study. The neurophysiological assessment protocols included measures of cortical and spinal cord evoked potentials, H-reflex excitability, and peripheral nerve conduction. Prior to the procedure, both patients had significant deficits on some of the neurophysiological measures, for example, lower extremity cortical evoked potentials. However, robust measures of intact pathways, such as upper extremity cortical evoked potentials, were also observed preoperatively in both patients. Thus, it was anticipated that conduction in these intact pathways could be at risk either from complications from the transplantation procedure and/or from continued expansion of the syrinx. Following the transplantation procedure, no negative changes were observed in any of the neurophysiological measures in either patient. In addition, patient 1 showed a decrease in the rate potentiation of tibial H-reflexes on the right side and an increase in the response probability of left tibial H-reflexes. The results of this postoperative longitudinal assessment provide a first-level demonstration of the safety of the intraspinal neural tissue transplantation procedure. However, the consideration of safety is currently limited to the grafting procedure itself, since the long-term fates of the donor tissue in these two patients remain to be shown more definitively.

Molecular biology of degenerative disc disease.

The intervertebral disc is a complex anatomic and biochemical structure. It is composed primarily of fibrocytes and chondrocytes that are anatomically segregated in an elaborate avascular macromolecular matrix of collagen and proteoglycans. Degenerative processes associated with aging and trauma result in morphological and molecular changes to the disc. Morphological changes are observed as dehydration, fissuring, and tearing of the nucleus, annulus and endplates. On the molecular level, degenerative changes include decreased diffusion, decreased cell viability, decreased proteoglycan synthesis, and alteration in collagen distribution. The role of inflammatory mediators in these processes, and the potential use of growth factors to delay or reverse the degenerative cascade, is poorly understood. However, these areas are under active investigation, the results of which may soon contribute significantly to our understanding of degenerative disc disease.

Necrotizing sarcoid granulomatosis mimicking an intracranial neoplasm: clinicopathologic features and review of the literature.

We present a unique case of biopsy-proven necrotizing sarcoidosis involving the central nervous system (CNS) in a 52-year-old woman. The patient presented with a 3-month history of left-sided headache and sharp, shooting pains on the left side of her face. She also has a previous history of sarcoidosis, histopathologically confirmed on parotid gland biopsy 24 years before. Imaging studies of the present lesion revealed a 1.8 x 1.4-cm mass in the left temporal lobe with signal intensity suggestive of meningioma or low-grade glial neoplasm. Surgical resection was initiated, and intraoperative consultation with frozen sections revealed granulomata. The lesion was biopsied, and surgical intervention was terminated. Permanent sections failed to reveal bacteria, mycobacteria, fungi, or foreign bodies. A diagnosis of necrotizing neurosarcoidosis was rendered. The patient was administered steroid therapy and clinically responded favorably. At the most recent follow-up almost 2 years later, there was no evidence of recurrence or progression. Necrotizing sarcoidosis has been reported most commonly in the lungs and rarely in other organ systems. We report the first histologically proven case involving the CNS as well as a rare example of sarcoidosis and necrotizing sarcoid granulomatosis in the same patient. Sarcoidosis and its necrotizing variant should be considered in the differential diagnosis of a granulomatous mass lesion involving the CNS, particularly in the context of a history of systemic disease.

Endoscopic foraminotomy using MED system in cadaveric specimens.

STUDY DESIGN: Four cadavers had cervical foraminotomies performed at noncontiguous levels using either the standard open technique or the microendoscopic technique. OBJECTIVES: To evaluate the feasibility of using a minimally invasive technique for posterior decompression of cervical disc disease. SUMMARY OF BACKGROUND DATA: Even though the anterior approach is more commonly performed for the treatment of cervical disc disease, the posterior approach has distinct advantages in selected cases of foraminal stenosis and posterolateral disc herniation. Current technique, however, requires extensive muscle dissection, and is, therefore, subject to significant morbidity. METHODS: Each of four cadavers had posterior cervical foraminotomies performed using either the MICROENDOSCOPIC (MED) technique, or the standard open technique. Three noncontiguous levels were decompressed using one technique, and the other technique was used for the adjacent contralateral decompression. Each specimen was then evaluated with postoperative myelogram/CT and open dissection. Laminotomy size, length of root decompressed, and percentage of facet removed were measured. RESULTS: Average vertical diameter decompression and percentage of facet removed were significantly greater for the MED technique than for the open technique. Transverse diameter of the laminotomy area and the average length of decompressed root were not significantly different between the techniques. CONCLUSION: Posterior cervical foraminotomy, using the microendoscopic technique, is technically feasible and may be applicable to the treatment of foraminal stenosis and laterally located cervical disc herniation. Studies in live animals are currently examining techniques for hemostasis.

Complex atlantoaxial fractures.

OBJECT: The authors conducted a retrospective study to evaluate the treatment of complex C1-2 fractures. METHODS: There were 10 cases of complex C1-2 fractures. Six patients were men (median age 58 years) and four patients were women (median age 55.5 years). Injuries resulted from seven falls, two motor vehicle accidents, and one diving incident. Three patients suffered from upper-extremity weakness. Neurological function in seven patients was intact preoperatively. Fracture combinations included six Jefferson/Type II odontoid, two anterior ring/Type II odontoid, one posterior ring/Type II odontoid, and one posterior ring/Type III odontoid/Type III hangman's fracture. All patients underwent surgery, five after halo immobilization for an average of 4 months failed to provide stability. Treatment included placement of six odontoid screws, one posterior C1-2 transarticular screw, one odontoid screw with anterior C1-2 transarticular screw fixation, one C1-2 transarticular screw with C1-2 Songer cable fusion, and one odontoid screw with bilateral C-2 pedicle screw fixation. Specific treatment was determined by the combination of fractures. Postoperatively, all patients were immobilized in a hard collar for 3 months. There were no intraoperative surgery-related complications. The mean follow-up period was 28.5 months. Neurological recovery was observed in one of three patients who presented with neurological deficits. Fusion occurred in all cases. CONCLUSIONS: The goals in treating these complex fractures are to achieve early maximum stability and minimum reduction in range of motion. These are often competing phenomena. Frequently in cases of atlas-axis fracture, odontoid screw fixation combined with hard collar immobilization is the best therapy, provided the transverse atlantal ligament is competent. If not, C1-2 stabilization with placement of transarticular screws is required for best results.

Complications during anterior surgery of the lumbar spine: an anatomically based study and review.

Procedures involving anterior surgical decompression and fusion are being performed with increasing frequency for the treatment of a variety of pathological processes of the spine including trauma, deformity, infection, degenerative disease, failed-back syndrome, discogenic pain, metastases, and primary spinal neoplasms. Because these operations involve anatomy that is often unfamiliar to many neurological and orthopedic surgeons, a significant proportion of the associated complications are not related to the actual decompressive or fusion procedure but instead to the actual exposure itself. To understand the nature of these injuries, a detailed anatomical study and dissection was undertaken in six cadaveric specimens. Critical structures at risk in the abdomen and retroperitoneum were identified, and their anatomical relationships were categorized and photographed. These structures included the psoas muscle, kidneys, ureters, diaphragm and crura, esophageal hiatus, thoracic duct, greater splanchnic nerves, phrenic nerves, sympathetic chains, medial arcuate ligament, superior and inferior hypogastric plexus, segmental and radicular vertebral vessels, aorta, vena cava, median sacral artery, common iliac vessels, iliolumbar veins, lumbosacral plexus, and presacral hypogastric plexus. Based on these dissections and an extensive review of the literature, the authors provide a detailed anatomically based discussion of the complications associated with anterior lumbar surgery.

Anterior cervical corpectomy for cervical spondylotic myelopathy.

OBJECTIVE: To evaluate the efficacy of anterior surgery for the treatment of cervical spondylotic myelopathy, we have reviewed our experience with anterior cervical corpectomy (ACC) at the University of Florida, specifically analyzing neurological outcomes and complications. These results have been compared with historical control subjects receiving laminectomy or "no treatment." METHODS: Between 1982 and 1992, 93 ACC operations were performed for the primary diagnosis of cervical spondylotic myelopathy. This consecutive series of patients was reviewed retrospectively. Age, gender, pre- and postoperative myelopathy severity, number of levels decompressed, and neurological complications were assessed. Myelopathy severity was graded using the Nurick myelopathy grading system. The average follow-up period was 39 months (range, 2-137 mo). RESULTS: Symptomatic improvement was achieved for 92% of patients (F = 28.9, df = 2172, P < 0.001). Nurick scores reflected improvement for 86% of patients, with the conditions of 13% remaining unchanged and only one patient showing worsening. Preoperative myelopathy severity was weakly correlated with age (P < 0.05) but was not correlated with gender or number of levels decompressed. Similarly, postoperative myelopathy severity was not significantly correlated with age, gender, preoperative myelopathy severity, or number of levels decompressed. ACC-treated patients showed an average improvement of 1.24 points on the Nurick scale, compared with an improvement of 0.07 points for patients treated with laminectomy (P < 0.001) and a deterioration of 0.23 points for patients undergoing conservative treatment (P < 0.001). Complications were slightly more likely to occur in older patients (P < 0.05). The number of levels decompressed was not significantly correlated with complications. Only one permanent neurological complication was seen in this series of patients. CONCLUSION: We conclude that ACC is a safe and effective treatment for cervical spondylotic myelopathy. In an average of 39 months, ACC showed improved results in terms of myelopathy scores, compared with historical control subjects receiving either no treatment or laminectomy. Age, gender, preoperative myelopathy severity, and extent of disease were not negative predictors of clinical outcomes.

Review: complications of surgery for thoracic disc disease.

BACKGROUND: Thoracic discectomy has evolved over the last 60 years from resection through standard laminectomy, to posterolateral procedures to open thoracotomy and finally thoracoscopy. Comparison of relative morbidity and mortality between these approaches is now possible. METHODS: Peer-reviewed publications reporting clinical data relating to thoracic discectomy, and which provided sufficient information to enable adequate assessment of mortality and morbidity were reviewed. These articles were determined via review of the results of MedLine searches and articles gathered through compilation of references from those articles. RESULTS: Articles reviewed spanned a period of over 60 years. Surgical procedures used for thoracic discectomy included laminectomy, pediculectomy, costotransversectomy, lateral extracavitary, transverse arthropediculectomy, anterolateral thoracotomy, and thoracoscopy. Complications included death, paralysis, paresis, loss of bowel and/or bladder control, pulmonary embolism, pneumonia, atelectasis, compression fracture, infection, pleural tear, bowel obstruction, and anesthesia dolorosa. Mortality dropped to nearly zero after development of anterior and posterolateral approaches. Morbidity seems relatively similar between most procedures other than laminectomy. Not enough procedures have been reported using thoracoscopy to adequately assess its morbidity. CONCLUSION: Comparison of relative rates of morbidity and mortality between surgical approaches to thoracic discectomy suggest that laminectomy does not provide adequate access for the safe removal of these lesions. Choice of approach among the alternatives should be based on the evacuation of the herniated fragment and experience of the surgeon. Thoracoscopy, although promising, has not had sufficient time for evaluation of morbidity to make definite statements regarding its safety.

Lateral extracavitary approach to the thoracic and thoracolumbar spine.

Twenty-nine patients with anterior spinal cord compression underwent decompression and fusion through a laterally based approach to the thoracic and thoracolumbar spine. The lateral extracavitary approach allows access to the vertebral bodies as well as the posterior elements through a single incision. This approach was chosen for patients who had complicating medical conditions that made staged procedures less desirable. Ten men and 19 women with an average age of 53 years were studied. Diagnoses included post-traumatic deformity, metastatic disease, osteomyelitis, and primary neoplasms. Twenty-three patients had frank neurologic loss preoperatively, and 28 patients had significant medical comorbidities as evidenced by American Society of Anesthesiology classes II, III, and IV. One patient died postoperatively from pneumonia, which developed in a lung with metastatic disease, and two patients developed seromas that subsequently became infected. The average intensive care unit stay was less than 2 days. Patients remained intubated for an average of 13 hours after surgery. In this population of medically compromised patients with difficult spinal disease, the lateral extracavitary approach provided an effective means of one-stage treatment. Patients tolerated the procedure, and cardiopulmonary complications were minimal. This approach is most appropriate in patients who require posterior stabilization in conjunction with anterior stabilization.

Primary reconstruction for spinal infections.

Primary reconstruction using bone grafts and instrumentation for spinal infections remains controversial. Between 1991 and 1993, 27 infections of the spinal column were treated at the Department of Neurosurgery of the University of Florida. Of the 27 cases 20 (six cervical, eight thoracic, and six lumbar spine) required surgical debridement and spinal reconstruction to maximize eradication of the infection and maintenance of spinal alignment. All of the cervical and lumbar cases were caused by bacterial infections, and two of eight thoracic cases were caused by tuberculous infections. Spinal arthrodesis was performed in all cases: interbody grafts were used in 18 procedures and posterolateral onlay grafts in 14. Interbody grafts were autologous in 10 cases (six rib and four iliac crest) and allograft in eight (six fibular and two humerus). All of the posterolateral onlay grafts were autologous (three rib and 11 iliac crest). Spinal instrumentation was used in 15 cases: four with Caspar plates and 11 with posterior segmental fixation (five hook/rod constructs and six screw/rod constructs). Seventeen of 20 patients achieved improved clinical status postoperatively and 18 of 20 showed radiographic evidence of bone fusion. Antibiotic drugs were administered parenterally for an average of 6 weeks followed by a 3-month course of oral antibiotic medications. Tuberculous infections were treated for 1 year with antibiotic therapy. The average follow-up period was 37 months from surgery and 31 months after completion of treatment with antibiotic drugs. The authors conclude that primary arthrodesis and instrumentation can be performed in acute spinal infections; however, successful management depends on aggressive debridement of infectious foci and prolonged treatment with parenteral antibiotic drugs.

Outcome analysis in lumbar spine: instabilities/degenerative disease.

In summary, expectations for outcome analysis have changed over the last several years. It is no longer the case that outcome analysis is expected to be done by academic institutions alone. Surgeons in private practice are rapidly approaching the time when outcome analysis of personal results will be necessary for competitive marketing purposes. In addition, the definition of outcome analysis has been considerably expanded from medical outcome to include functional outcome, return to work, quality of life, patient satisfaction, and cost-effectiveness. The above discussion has considered several aspects of data outcome analysis for degenerative disease of the lumbar spine. It is the intent of this review to help surgeons prepare themselves for changing expectations in their new medical environment.

Prospective, multicenter study of spinal cord stimulation for relief of chronic back and extremity pain.

STUDY DESIGN: This prospective, multicenter study was designed to investigate the efficacy and outcome of spinal cord stimulation using a variety of clinical and psychosocial outcome measures. Data were collected before implantation and at regular intervals after implantation. This report focuses on 70 patients who had undergone 1 year of follow-up treatment at the time of data analysis. OBJECTIVES: To provide a more generalizable assessment of long-term spinal cord stimulation outcome by comparing a variety of pain and functional/quality-of-life measures before and after management. This report details results after 1 year of stimulation. SUMMARY OF BACKGROUND DATA: The historically diverse methods, patient selection criteria, and outcome measures reported in the spinal cord stimulation literature have made interpretation and comparison of results difficult. Although short-term outcomes are generally consistent, long-term outcomes of spinal cord stimulation, as determined by prospective studies that assess multidimensional aspects of the pain complaint among a relatively homogeneous population, are not well established. METHODS: Two hundred nineteen patients were entered at six centers throughout the United States. All patients underwent a trial of stimulation before implant of the permanent system. Most were psychologically screened. One hundred eighty-two patients were implanted with a permanent stimulating system. At the time of this report, complete 1-year follow-up data were available on 70 patients, 88% of whom reported pain in the back or lower extremities. Patient evaluation of pain and functional levels was completed before implantation and 3, 6, 12, and 24 months after implantation. Complications, medication usage, and work status also were monitored. RESULTS: All pain and quality-of-life measures showed statistically significant improvement during the treatment year. These included the average pain visual analogue scale, the McGill Pain Questionnaire, the Oswestry Disability Questionnaire, the Sickness Impact Profile, and the Back Depression Inventory. Overall success of the therapy was defined as at least 50% pain relief and patient assessment of the procedure as fully or partially beneficial and worthwhile. Using this definition, spinal cord stimulation successfully managed pain in 55% of patients on whom 1-year follow-up is available. Complications requiring surgical intervention were reported by 17% (12 of 70) of patients. Medication usage and work status were not changed significantly. CONCLUSIONS: This prospective, multicenter study confirms that spinal cord stimulation can be an effective therapy for management of chronic low back and extremity pain. Significant improvements in many aspects of the pain condition were measured, and complications were minimal.

Percutaneous lumbosacral fixation and fusion: anatomic study and two-year experience with a new method.

This anatomic and clinical study describes a transsacral, percutaneous approach for fixation and fusion of the L5-S1 disc. A tunnel is created into the L5-S1 disc from this approach, permitting disc removal, bone grafting, and placement of two nine-millimeter diameter titanium screws into the body of L5. There were no complications referable to screw placement, and eight of nine patients had successful fusion.

Posterolateral approach to intradural extramedullary thoracic tumors.

Six ventrally located intradural thoracic tumors were successfully resected through the posterolateral approach. This approach allows direct visualization of the ventral and dorsal boundaries of the tumor with minimal manipulation of the spinal cord. Compared to the traditional laminectomy, the operative time is increased but visualization of the tumor and spinal cord is markedly improved. Compared to the transthoracic approach, the posterolateral approach has fewer potential complications and eliminates the necessity of vertebrectomy. Neurological improvement occurred in all six patients. It is believed that this approach offers significant advantages for the treatment of ventrally located intradural thoracic tumors, and should be considered an alternative to the transthoracic approach.