Emerging techniques in the minimally invasive treatment and management of thoracic spine tumors.

Over the past decade, the development and refinement of minimally invasive spine surgery techniques has lead to procedures with the potential to minimize iatrogenic and post-operative sequelae that may occur during the surgical treatment of various pathologies. In a similar manner, parallel advances in other current treatment technologies have led to the development of other minimally invasive treatments of spinal malignancies. These advances include percutaneous techniques for vertebral reconstruction, including vertebroplasty and kyphoplasty, the development of safe and effective spinal radiosurgery, and minimal-access spinal surgical procedures that allow surgeons to safely decompress and reconstruct the anterior spinal column. The advent of these new techniques has given modern practitioners treatment options in situations where they previously were limited by the potentially significant morbidities of the available techniques. Here, the authors discuss the application of current minimally invasive technologies in the treatment of malignancies of the thoracic spine, focusing on vertebral kyphoplasty, spinal radiosurgery, and minimally invasive spinal decompression techniques. The author's describe how these emerging treatment options are significantly expanding the options open to clinicians in the treatment of thoracic spinal column malignancies. Specific illustrative case examples are provided. The development of these techniques has the potential to improve clinical outcomes, limit surgical morbidity, and also improve the safety and efficiency of treatment pathways.

Ossification of the posterior longitudinal ligament: pathogenesis, management, and current surgical approaches. A review.

Ossification of the posterior longitudinal ligament (OPLL) is an important cause of cervical myelopathy that results from bony ossification of the cervical or thoracic posterior longitudinal ligament (PLL). It has been estimated that nearly 25% of patients with cervical myelopathy will have features of OPLL. Patients commonly present in their mid-40s or 50s with clinical evidence of myelopathy. On MR and CT imaging, this can be seen as areas of ossification that commonly coalesce behind the cervical vertebral bodies, leading to direct ventral compression of the cord. While MR imaging will commonly demonstrate associated changes in the soft tissue, CT scanning will better define areas of ossification. This can also provide the clinician with evidence of possible dural ossification. The surgical management of OPLL remains a challenge to spine surgeons. Surgical alternatives include anterior, posterior, or circumferential decompression and/or stabilization. Anterior cervical stabilization options include cervical corpectomy or multilevel anterior cervical corpectomy and fusion, while posterior stabilization approaches include instrumented or noninstrumented fusion or laminoplasty. Each of these approaches has distinct advantages and disadvantages. While anterior approaches may provide more direct decompression and best improve myelopathy scores, there is soft-tissue morbidity associated with the anterior approach. Posterior approaches, including laminectomy and fusion and laminoplasty, may be well tolerated in older patients. However, there often is associated axial neck pain and less improvement in myelopathy scores. In this review, the authors discuss the epidemiology, imaging findings, and clinical presentation of OPLL. The authors additionally discuss the merits of the different surgical techniques in the management of this challenging disease.

Minimally invasive percutaneous transpedicular screw fixation: increased accuracy and reduced radiation exposure by means of a novel electromagnetic navigation system.

BACKGROUND: Minimally invasive percutaneous pedicle screw instrumentation methods may increase the need for intraoperative fluoroscopy, resulting in excessive radiation exposure for the patient, surgeon, and support staff. Electromagnetic field (EMF)-based navigation may aid more accurate placement of percutaneous pedicle screws while reducing fluoroscopic exposure. We compared the accuracy, time of insertion, and radiation exposure of EMF with traditional fluoroscopic percutaneous pedicle screw placement. METHODS: Minimally invasive pedicle screw placement in T8 to S1 pedicles of eight fresh-frozen human cadaveric torsos was guided with EMF or standard fluoroscopy. Set-up, insertion, and fluoroscopic times and radiation exposure and accuracy (measured with post-procedural computed tomography) were analyzed in each group. RESULTS: Sixty-two pedicle screws were placed under fluoroscopic guidance and 60 under EMF guidance. Ideal trajectories were achieved more frequently with EMF over all segments (62.7% vs. 40%; p = 0.01). Greatest EMF accuracy was achieved in the lumbar spine, with significant improvements in both ideal trajectory and reduction of pedicle breaches over fluoroscopically guided placement (64.9% vs. 40%, p = 0.03, and 16.2% vs. 42.5%, p = 0.01, respectively). Fluoroscopy time was reduced 77% with the use of EMF (22 s vs. 5 s per level; p < 0.0001) over all spinal segments. Radiation exposure at the hand and body was reduced 60% (p = 0.058) and 32% (p = 0.073), respectively. Time for insertion did not vary between the two techniques. CONCLUSIONS: Minimally invasive pedicle screw placement with the aid of EMF image guidance reduces fluoroscopy time and increases placement accuracy when compared with traditional fluoroscopic guidance while adding no additional time to the procedure.

A Comparison of fixed-hole and slotted-hole dynamic plates for anterior cervical discectomy and fusion.

STUDY DESIGN: A retrospective review of clinical data at 1 institution was performed. OBJECTIVES: To compare the clinical and radiologic outcomes between fixed-hole and slotted-hole dynamic cervical plates. SUMMARY OF BACKGROUND DATA: Anterior cervical plating is commonly used to increase stability and promote spinal fusion. Two techniques, fixed-hole dynamic plating that uses variable angled screws and slotted-hole dynamic plating that permits sliding, are viable options, but there have been no clinical studies comparing their effectiveness. METHODS: Fifty-six patients at 1 institution having anterior cervical discectomy and fusion for degenerative disease over a 5-year period were entered into this study. Surgeries were performed with 1 of the dynamic plates for 1 to 3 levels. For the slotted-hole dynamic plate group, a slotted-hole plate was used (ABC, Aesculap, Tuttlingen, Germany or C-tek, Biomet, Parssipany, NJ) and for the fixed-hole dynamic plated group, a variable angled screw was used (C-tek, Biomet, Parssipany, NJ). Radiographic measurements included were graft subsidence, lordotic angle change from each end plate of fusion construct, and implant translation from end plates after a minimum of 12 months follow-up. Fusion state and clinical outcome using Odom's criteria were also evaluated. RESULTS: Demographics were not different among patient populations. The average age of the patients was 51.0 years (range: 27 to 77 y). Mean follow-up period was 20.6 months (range: 12 to 41 mo). Slotted-hole dynamic plates were used for 29 patients (ABC plate, 17; C-tek plate, 12) and fixed-hole dynamic plates for 27 patients. Clinical outcomes and pseudoarthrosis rates were similar for both types of plates. Radiographic measurements showed a statistically significant increased incidence of graft subsidence and implant translation with the slotted-hole dynamic plates. Loss of lordosis was also greater in the slotted-hole dynamic plated group, although the difference was not statistically significant. CONCLUSIONS: The use of a fixed-hole dynamic plate is more favorable in regards to graft subsidence and implant translation in the follow-up period, although clinical outcome and fusion rates are similar in patients with either the fixed-hole or slotted-hole dynamic plates.

Anatomical considerations for subaxial (C2) pedicle screw placement: a radiographic study with computed tomography in 93 patients.

STUDY DESIGN: Radiographic study. OBJECTIVE: More detailed anatomical knowledge of the C2 pedicle is required to optimize and minimize the risk of screw placement. The aim of this study was to evaluate the linear and angular dimensions of the true C2 pedicle using axial computed tomography. BACKGROUND DATA: Although earlier studies have analyzed the anatomy of the C2 pars interarticularis, little attention has been focused on the dimensions of the C2 pedicle. METHODS: Ninety-three patients (47 males, 46 females; mean age 48.4 y) who had previous cervical spinal computed tomography imaging were evaluated for this study. Axial images of the C2 pedicle were selected and the following pedicle parameters were determined: pedicle width (the mediolateral diameter of the pedicle isthmus, perpendicular to the pedicle axis) and pedicle transverse angle (PTA, ie, the angle between the pedicle axis and the midline of the vertebral body). RESULTS: The overall mean pedicle width was 5.8+/-1.2 mm. The mean pedicle width in male patients (6.0+/-1.3 mm) was greater than that in the female patients (5.6+/-1.1 mm). This difference was not found to be statistically significant (P=0.679). The overall mean PTA was 43.9+/-3.9 degrees. The mean PTA in male patients was 43.2+/-3.8 degrees, whereas that in female patients was 44.7+/-3.7 degrees. CONCLUSIONS: Given the significant variability in pedicle widths and the need for precise trajectory planning in pedicle cannulation, preoperative planning is absolutely mandatory. A significant percentage of patients have pedicle widths that may not accommodate screw fixation. In addition, the angle of entry into the C2 pedicle must be carefully measured for safe instrumentation at this level.

Clinical and Radiographic Outcomes After Minimally Invasive Transforaminal Lumbar Interbody Fusion-Early Experience Using a Biplanar Expandable Cage for Lumbar Spondylolisthesis.

BACKGROUND: Minimally invasive transforaminal lumbar interbody fusion (MIS TLIF) is a surgical technique frequently used to treat symptomatic lumbar spondylolisthesis. We aim to investigate the safety and efficacy of using a biplanar expandable cage in the treatment of symptomatic lumbar spondylolisthesis using a MIS TLIF approach. METHODS: A retrospective review of patient records was performed on patients who underwent MIS TLIF for symptomatic lumbar spondylolisthesis using the FlareHawk cage over a 12-month period. Patient demographics, as well as preoperative and postoperative clinical and radiographic outcome measures were recorded and analyzed. RESULTS: A total of 13 consecutive patients underwent MIS TLIF for symptomatic spondylolisthesis during the study period. The mean age was 60.2 ± 13.9 years, and 61.5% were female. The mean preoperative and postoperative slippage was 7.0 ± 3.0 mm and 1.0 ± 1.9 mm, respectively. The preoperative mean segmental lordosis was 5.1° ± 6.0°, mean anterior, posterior disc, and foraminal height were 9.1 ± 3.9 mm, 5.7 ± 1.5 mm, and 11.0 ± 2.0 mm, respectively. The postoperative mean segmental lordosis was 6.8° ± 4.7°, and mean anterior, posterior disc, and foraminal height were 11.4 ± 2.2 mm, 7.8 ± 1.0 mm, and 12.3 ± 1.3 mm. There was improvement in all radiographic parameters postoperatively. The mean Visual Analog Scale (VAS) back pain, VAS leg pain improved from 7.0 ± 2.9 and 5.1 ± 3.0 preoperatively to 3.1 ± 2.9 and 1.1 ± 1.7 at the latest clinic follow-up visit, respectively (P = .0081). The mean EuroQol-Five Dimensions (EQ5D) score improved from 0.37 ± 1.7 to 0.66 ± 0.23 after surgery. There was no subsidence, endplate violation, cage migration, or other implant-related complications. No patient required reoperation. CONCLUSIONS: The biplanar expandable cage is both safe and efficacious in treating symptomatic lumbar spondylolisthesis using the MIS TLIF approach. Spine surgeons should be familiar with the biplanar expandable cage technology and keep it in their armamentarium in surgical treatment of lumbar spondylolisthesis. LEVEL OF EVIDENCE: 4.

Surgical outcomes of elderly patients with cervical spondylotic myelopathy.

BACKGROUND: Cervical spondylotic myelopathy is a potentially serious neurologic disorder that commonly presents with gait difficulty and hand dysfunction. Because the development of CSM is in large part related to advanced spondylosis and degenerative disk disease, elderly patients appear to be at an increased risk to develop this condition. The surgical outcomes of this patient population have been understudied; the authors seek to report their clinical results in a series of patients with CSM older than 75 years who underwent surgical treatment. METHODS: This report is composed of a cohort of 36 elderly patients (older than 75 years) and 34 younger patients (younger than 65 years) who underwent decompressive surgery for CSM at one institution between 2001 and 2005. The patients' functional status was evaluated preoperatively and postoperatively using the mJOA disability scale. RESULTS: The mean follow-up time in the elderly group was 24 months, with a range from 12 to 48 months. There was a statistically significant improvement between mean preoperative (11.3) and postoperative (14.4) mJOA scores (P< .0001). The younger group had a higher neurologic recovery rate (71%) than the elderly group (59%); however, this was not statistically significant (P= .29). The postoperative complication rate in the elderly population (38%) was higher than in the younger group (6%; P= .002). CONCLUSION: Elderly patients with CSM are likely to obtain neurologic improvement after decompressive surgery. Their postoperative complication rate is higher than that of younger patients, yet most complications appear to be self limiting and do not adversely affect neurologic outcome.

Minimally invasive decompression for lumbar stenosis and disc herniation.

For decades, lumbar disc herniation and lumbar stenosis have been treated surgically via traditional open techniques. With recent emphasis on minimally invasive approaches in spine surgery, a number of new techniques has been introduced that are aimed at treating these 2 common pathological conditions. Currently the most widely used and efficacious minimally invasive technique for treating these disorders is direct decompression with minimally invasive surgery. Due to the scarcity of large randomized studies, however, it is difficult to compare the effectiveness and possible superiority of this technique with traditional decompression. Further studies are needed to evaluate this issue.

The results of beta-tricalcium phosphate coated hydroxyapatite (beta-TCP/HA) grafts for interbody fusion after anterior cervical discectomy.

STUDY DESIGN: The efficacy of tricalcium phosphate and hydroxyapatite (beta-TCP/HA) grafts was studied after anterior cervical discectomy (ACD). OBJECTIVE: This study presents our observations about the efficacy of beta-TCP/HA grafts after ACD. SUMMARY OF BACKGROUND DATA: Especially in the last 2 decades, fusion materials such as autograft and allograft, as well as different kind of cages were used to maintain fusion after ACD. METHODS: beta-TCP/HA grafts after ACD were used in 17 patients. The cervical and radicular pain was evaluated via visual analog scale (VAS) score preoperatively, at postoperative third week, and after 20 months (range: 18 to 24 mo) after the operation. The radiologic evaluations were done preoperatively, at postoperative first day and at the latest follow-up. The VAS, intervertebral space ratio, height of intervertebral disc space and neural foramen, and cervical and segmental lordosis angles were recorded preoperatively and during the postoperative follow-up period. The presence of fusion was controlled in computed tomography scans taken at the latest follow-up. RESULTS: Both clinical and radiologic evaluations yielded satisfactory results. VAS scores decreased significantly in all patients. The intervertebral space and neural foramen and intervertebral disc heights increased at postoperative day 1 but were found to be decreased at the latest follow-up (P<0.05). On the contrary the cervical and segmental lordosis angles decreased at postoperative day 1 but were found to be increased at the latest follow-up (P<0.05). There was a solid fusion in 16 out of 17 patients (94.11%). CONCLUSIONS: Although there was a loss of the initially obtained neural foraminal and disc height, the application of beta-TCP/HA graft after ACD resulted in a high rate of fusion and patient satisfaction. Additionally, the cervical and segmental lordosis was preserved. We concluded that it is a good alternative to current methods to maintain cervical alignment and fusion after ACD.

Cytokines in umbilical cord blood-derived cellular product: a mechanistic insight into bone repair.

AIM: Umbilical cord blood (UCB) finds frequent applications in regenerative medicine. We evaluated the role of cytokines present in a uniquely processed, UCB-derived cellular allograft product (UCBp). MATERIALS & METHODS: Luminex multiplex assay and standard cell biology methods were employed. RESULTS: Study with allografts from 33 donors identified 44 quantifiable cytokines in the UCBp derived conditioned media (CM). The UCBp-CM elevated proliferation and migration rates of mesenchymal stem cells (MSCs) and bone marrow stromal cells. Moreover, UCBp-CM induced secretion of VEGF-A and osteoprotegerin, which promoted angiogenesis of endothelial cells and positively influenced the osteogenic differentiation of MSCs, respectively. CONCLUSION: Cytokines in UCBp stimulate cellular processes important for bone regeneration, making UCBp an excellent candidate for potential applications in orthopedic procedures like bone non-union and spinal fusion.

Minimally invasive operative management for lumbar spinal stenosis: overview of early and long-term outcomes.

Standard open posterior decompression is well established and familiar to virtually all spine surgeons. However, this traditional surgical treatment of lumbar spinal stenosis (LSS) is often associated with significant postoperative pain, disability, and dysfunction. This article reviews the use of a minimally invasive microendoscopic approach for bilateral decompression of lumbar stenosis by way of a unilateral approach. This technique has been shown to provide symptomatic relief equivalent to that of open discectomy, with significant reductions in operative blood loss, postoperative pain, hospital stay, and narcotic usage. Furthermore, the article explains the rationale, indications, and surgical techniques for minimally-invasive LSS surgery and presents the authors' 4-year outcomes data.

Treatment of lumbar spinal stenosis with a total posterior arthroplasty prosthesis: implant description, surgical technique, and a prospective report on 29 patients.

OBJECT: Total disc replacement is an alternative to lumbar fusion, but patients with spinal stenosis, spondylolisthesis, and facet arthropathy are often excluded from this procedure because increased adjacent-segment motion can exacerbate dorsal spondylotic changes. In such cases of degenerative spondylolisthesis with stenosis, decompression and fusion remain the gold standard of treatment. To avoid attendant loss of motion at the treated segment, the TOPS system is a novel total posterior arthroplasty prosthesis that allows for an alternative dynamic, multiaxial, three-column stabilization and motion preservation. The purpose of this study is to report preliminary surgical data and clinical outcomes in patients treated with the TOPS lumbar total posterior arthroplasty system. METHODS: Twenty-nine patients were enrolled in a nonrandomized, multicenter, prospective pilot study outside the US. All patients had spinal stenosis and/or spondylolisthesis at L4-5 due to facet arthropathy. Radiographs and scores on outcome measures including the visual analog scale (VAS) for pain, Oswestry Disability Index (ODI), Short Form-36, and Zurich Claudication Questionnaire were prospectively recorded before surgery and at 6-week, 3-month, 6-month, and 1-year intervals after surgery. Prior to instrumentation, a bilateral total facetectomy and laminectomy at L4-5 or L3-4 was performed via a standard midline posterior approach. After decompression, the TOPS screws were inserted into four pedicles to achieve maximal purchase with triangulating bicortical trajectories. An appropriately sized TOPS arthroplasty implant was then applied. The mean surgical time was 3.1 hours, and patients' clinical status improved significantly following treatment with the TOPS device. The mean ODI score decreased compared with baseline by 41% at 1 year, and the 100-mm VAS score declined by 76 mm over the same time period. Radiographic analysis showed that lumbar motion was maintained, disc height was preserved, and no evidence of screw loosening was found. No device malfunctions or migrations and no device-related adverse events were reported during the study. CONCLUSIONS: The TOPS total posterior arthroplasty system represents a novel, dynamic, posterior arthroplasty device that provides multiaxial stability in flexion, extension, rotation, and lateral bending after total facetectomy and neural decompression. The surgical data indicate that it can be safely applied via a traditional approach with low surgical morbidity and excellent 1-year functional and radiographic outcomes in patients with degenerative spondylolisthesis accompanied by stenosis and back pain.

Minimally invasive posterior cervical arthrodesis and fixation.

This article describes the use of minimally invasive posterior cervical arthrodesis and internal fixation for the subaxial cervical spine. Such systems vary by the angulation of their screws and in the degree of the constraint placed at the screw-rod interface. The polyaxial tulip or islet connectors of the screws are able to angle medially, laterally, and straight, with varying degrees of rotational freedom in each direction, thus making segmental fixation more easily achievable from a top-loading approach and allowing for the possibility of minimally invasive posterior cervical fixation.

Treatment of lumbar synovial cysts using minimally invasive surgical techniques.

OBJECT: Lumbar synovial cysts are a potential cause of radiculopathy and back pain, and the definitive treatment is the complete excision of the cyst. This report summarizes the authors' preliminary clinical experience with the minimally invasive resection of lumbar synovial cysts. METHODS: Nineteen patients (nine men and 10 women) with symptomatic synovial cysts underwent minimally invasive resection. The mean patient age was 64 years of age (range 43-80 years). The presenting symptom was radiculopathy in 16 patients, low-back pain in two, and lower-extremity weakness in one. There were 16 cases of a cyst located at the L4-5 level, two at L3-4, and one at L5-S1. The mean cyst diameter was 13.7 mm (range 3-30 mm). The mean follow-up time was 16 months (range 4-29 months). Clinical outcomes were graded, based on the Macnab modified criteria, as excellent, good, fair, or poor. Eighteen patients (95% of cases) reported either excellent (10 patients) or good (eight patients) results, and a fair result was reported by one patient (5% of cases). The mean operative time was 158 minutes (range 75-270 minutes), and the average intraoperative blood loss was 31 ml (range 10-100 ml). Two patients had intraoperative dural tears that resulted in cerebrospinal fluid leaks that resolved following primary closure. CONCLUSIONS: Synovial cysts can be safely and effectively treated using minimally invasive surgical techniques. Long-term follow up is required to determine whether this approach results in less need for fusion than conventional surgical approaches.

A novel minimally invasive presacral approach and instrumentation technique for anterior L5-S1 intervertebral discectomy and fusion: technical description and case presentations.

OBJECT: The authors describe a new paracoccygeal approach to the L5-S1 junction for interbody fusion with transsacral instrumentation. The purpose of this technical note is to demonstrate a novel surgical approach, technique, and instrumentation system for the treatment of L5-S1 instability in degenerative disc disease and spondylolisthesis. METHODS: This technical note highlights the AxiaLif (TranS1) transsacral system as an alternative method to transforaminal lumbar interbody fusion or posterior lumbar interbody fusion. Via a novel presacral approach corridor, a truly percutaneous L5-S1 discectomy, interbody distraction, and fixation are achieved, and retroperitoneal viscera and dorsal neural elements are avoided. Percutaneous pedicle screw fixation is then used to provide additional stabilization at the treated level. CONCLUSIONS: This novel technique of interbody distraction and fusion via a truly percutaneous approach corridor allows for circumferential treatment of the lower lumbar segments with minimal risk to the anterior organs and dorsal neural elements.

A novel percutaneous system for bone graft delivery and containment for elevation and stabilization of vertebral compression fractures. Technical note.

OBJECT: Vertebroplasty and kyphoplasty are minimally invasive procedures used to treat persistently symptomatic vertebral compression fractures (VCFs). Both interventions usually involve injection of polymethyl methacrylate (PMMA). The purpose of this technical note was to review the theory and surgical technique for a novel percutaneous system for fracture reduction and stabilization of VCFs by using bone graft. METHODS: This technical note highlights the Optimesh system as an alternative method of minimally invasive VCF reduction and stabilization with the delivery of a bone graft containment device. Instead of using PMMA as in vertebroplasty or kyphoplasty, this system allows the delivery of allograft and/or autograft bone, with its osteoinductive, osteoconductive, and osteogenic properties. CONCLUSIONS: This system allows for restoration of sagittal alignment of the spine with direct control of bone graft delivery by using a mesh graft containment device that allows for ingrowth of new bone and vascular tissue.

Minimally invasive cervical microendoscopic foraminotomy: an initial clinical experience.

OBJECTIVE: We have previously reported the feasibility of using the microendoscopic foraminotomy (MEF) technique in a cadaveric study. We now report our initial clinical experience with this novel technique. METHODS: From March 1998 to January 2001, we prospectively used the MEF technique in 25 patients with cervical root compression from either foraminal stenosis or disc herniation. The patients' demographic, clinical presentation, surgical, and outcome data were recorded. Another 26 patients treated via open cervical laminoforaminotomy were used for comparison. RESULTS: MEF cases involved less blood loss (138 versus 246 ml per level). MEF patients recovered more rapidly, had a shorter postoperative stay (20 versus 68 hours), and needed fewer narcotics (11 versus 40 equivalents). There were two durotomies after MEF. Overall, our initial experience with the MEF procedure yielded symptomatic improvement for approximately 87 to 92% of patients, depending on which symptom was analyzed. After MEF (mean follow-up, 16 mo; minimum follow-up, 1 year), patients with radiculopathy experienced resolution of their symptoms in 54%, improvement in 38%, and no change in 8% of cases. For open surgery, radiculopathy resolved in 48%, improved in 40%, and remained unchanged in 12%. For neck pain, the MEF results were 40% resolved, 47% improved, and 13% unchanged. Open results for neck pain were 33% resolved, 56% improved, and 11% unchanged. Overall, there was no significant difference in outcomes between the groups. CONCLUSION: The MEF technique yielded clinical results equivalent to those of the open surgical group as well as to those described in the literature. MEF patients, however, had less blood loss, shorter hospitalizations, and a much lower postoperative pain medication requirement.

Microendoscopic decompressive laminotomy for the treatment of lumbar stenosis.

OBJECTIVE: By modifying existing microendoscopic discectomy techniques, we previously developed a novel surgical treatment of lumbar stenosis and validated its ability to achieve a thorough decompression in a cadaveric study. We now describe our clinical experience with this new, minimally invasive microendoscopic decompressive laminotomy (MEDL) technique. METHODS: A MEDL was performed in 25 patients with classic features of lumbar stenosis. By use of a fluoroscopically guided percutaneous technique, the working portal was docked on the lamina with minimal soft-tissue injury. With the angle of the endoscope combined with an oblique entry, a bilateral bony and ligamentous decompression was achieved under the midline, thereby preserving the supraspinous-interspinous ligaments and contralateral musculature. A second group of 25 patients treated with open decompression was used for comparison. RESULTS: Effective circumferential decompression was achieved in the majority of patients. The results for the MEDL group were as follows: operative time, 109 minutes per single level; blood loss, 68 ml; and postoperative stay, 42 hours. The results for the open-surgery group were as follows: operative time, 88 minutes; blood loss, 193 ml; and postoperative stay, 94 hours. The MEDL group needed significantly less narcotic medication after surgery. Overall, 16% of the MEDL patients reported resolution of their back pain, 68% improved symptomatically, and 16% remained unchanged. The outcome of the open group was very similar. CONCLUSION: Compared with an equivalent open technique, MEDL appears to offer a similar short-term clinical outcome with a significant reduction in operative blood loss, postoperative stay, and use of narcotics. This lower surgical stress, decreased tissue trauma, and quicker recovery are particularly important in this elderly population of patients.

Thoracoscopic-assisted treatment of thoracic and lumbar fractures: a series of 371 consecutive cases.

OBJECTIVE: Conventional approaches for the treatment of thoracic and thoracolumbar fractures require extensive surgical exposure, often leading to significant postoperative pain and morbidity. Thoracoscopic spinal surgery was performed to reduce the morbidity of these approaches while still achieving the primary goals of spinal decompression, reconstruction, and stabilization. METHODS: Between May 1996 and May 2001, 371 patients with fractures of the thoracic and thoracolumbar spine (T3-L3) were treated with a thoracoscopically assisted procedure. In the first 197 patients, a conventional open anterior plating system was used. The last 174 patients were treated with the MACS-TL system (Aesculap, Tuttlingen, Germany), which was designed specifically for endoscopic placement, thereby significantly reducing operative times. RESULTS: Seventy-three percent of the fractures were located at the thoracolumbar junction. In 49% of patients, mobilization of the diaphragm was performed to expose the fracture, with later repair. Both x-ray canal compromise and neural deficit were present in 15% of patients. In 35% of patients, a stand-alone anterior thoracoscopic reconstruction was performed. In 65% of patients, a supplemental posterior pedicle-screw construct was also placed either before or after the anterior construct. A steep learning curve was present, with an average operating time of 300 minutes in the first 50% of cases and an average of 180 minutes with the MACS-TL system. The severe complication rate was low (1.3%), with one case each of aortic injury, splenic contusion, neurological deterioration, cerebrospinal fluid leak, and severe wound infection. Compared with a group of 30 patients treated with open thoracotomy, thoracoscopically treated patients required 42% less narcotics for pain treatment after the operation. CONCLUSION: A complete anterior thoracoscopically assisted reconstruction of thoracic and thoracolumbar fractures can be safely and effectively accomplished, thereby reducing the pain and morbidity associated with conventional thoracotomy and thoracolumbar approaches. Although the learning curve is steep, the functional and cosmetic benefits to the patient warrant the difficult training process.

Minimally invasive percutaneous posterior lumbar interbody fusion.

OBJECTIVE: The wide exposure required for a standard posterior lumbar interbody fusion (PLIF) can cause unnecessary trauma to the lumbar musculoligamentous complex. By combining existing microendoscopic, percutaneous instrumentation and interbody technologies, a novel, minimally invasive, percutaneous PLIF technique was developed to minimize such iatrogenic tissue injury (MIP-PLIF). METHODS: The MIP-PLIF technique was validated in three cadaveric torsos with six motion segments decompressed and fused. Preoperative variables measured from imaging included interpedicular distance, pedicular height and width, interspinous distance, lordosis, intervertebral height, Cobb angle, and foraminal height and volume. Using the METRx and MD spinal access systems (Medtronic Sofamor Danek, Memphis, TN), bilateral laminotomies were performed using a hybrid of microsurgical and microendoscopic techniques. The intervertebral disc spaces were then distracted and prepared with the Tangent (Medtronic Sofamor Danek) interbody instruments. Either a 10 or 12 by 22 mm interbody graft was then placed. Using the Sextant (Medtronic Sofamor Danek) system, percutaneous pedicle screw-rod fixation of the motion segment was completed. We then applied MIP-PLIF in three patients. RESULTS: For segments with preoperative intervertebral/foraminal height loss, MIP-PLIF was effective in restoring both heights in all cases. The amount of improvement (9.7 to 38% disc height increase; 7.7 to 29.9% foraminal height increase) varied directly with the size of the graft used and the original degree of disc and foraminal height loss. Segmental lordosis improved by 29% on average. Graft and screw placement was accurate in the cadavers, except for a single Grade 1 screw violation of one pedicle. The average operative time was 3.5 hours per level. In our three clinical cases, the MIP-PLIF procedure required a mean of 5.4 hours, estimated blood loss was 185 ml, and inpatient stay was 2.8 days, with no intravenous narcotic use after 2 days in any of the patients. All screw and graft placements were confirmed. CONCLUSION: A complete PLIF procedure can be safely and effectively performed using minimally invasive techniques, thereby potentially reducing the pain and morbidity associated with standard open surgery. Prospective, randomized outcome studies will be required to validate the efficacy of this exciting new surgical technique.