Tubular Retractor System Research Articles

Microendoscopic lumbar discectomy: Technique and results of 188 cases

Background:Discectomy performed open or with an operating microscope remains the standard surgical management. Tubular retractor system is being increasingly used. Potential benefits include less muscle and local damage, better cosmesis, decreased pain and operative time and faster recovery after surgery. We have evaluated the outcome of micro endoscopic discectomy (MED) utilizing tubular retractors in terms of safety and efficacy of the technique.Materials and Methods:188 consecutive patients who underwent surgery for herniated disc using the tubular retractors between April 2007 and April 2012 are reported. All patients had a preoperative MRI (Magnetic Resonance Imaging) and were operated by a single surgeon with the METRx system (Medtronic, Sofamor-Danek, Memphis, TN) using 18 and 16 mm ports. All patients were mobilized as soon as pain subsided and discharged within 24-48 hours post surgery. The results were evaluated by using VAS (Visual Analog Scale 0-5) for back and leg pain and ODI (Oswestry Disability Index). Patients were followed up at intervals of 1 week, 6 weeks, 3 months, 6 months, 12 months and 2 years.Results:The mean age of patients was 46 years (range 16-78 years) and the sex ratio was 1.5 males to 1 female. The mean followup was 22 months (range 8-69 months). The mean VAS scale for leg pain improved from 4.14 to 0.76 (P < 0.05) and the mean VAS scale for back pain improved from 4.1 to 0.9 (P < 0.05). The mean ODI changed from 59.5 to 22.6 (P < 0.05). The mean operative time per level was about 50 minutes (range 20-90 minutes). Dural punctures occurred in 11 (5%) cases. Average blood loss was 30 ml (range 10-500 ml). A wrong level was identified and later corrected in a case of revision discectomy. Four patients with residual disc-herniation had revision MED and three patients with recurrent disc herniation later underwent fusion. One patient had wound infection which needed a debridement.Conclusion:MED for herniated discs effectively achieves the goals of surgery with minimal access. The advantages of the procedure are cosmesis, early postoperative recovery and minimal postoperative morbidity.

Microsurgical treatment and outcome of pediatric supratentorial cerebral cavernous malformation.

ObjectiveThe purpose of this study was to investigate the clinical features and outcomes of pediatric cavernous malformation (CM) in the central nervous system.MethodsTwenty-nine pediatric patients with supratentorial CM underwent microsurgical excision. In selected cases, transparent tubular retractor system (TTRS) was used to reduce retraction injury and intraoperative neuromonitoring (IONM) was held to preserve functioning cortex. Patients' demographics and symptoms were reviewed and surgical outcomes were discussed.ResultsThe main initial clinical manifestations included the following : seizures (n=13, 45%), headache (n=7, 24%), focal neurological deficits (n=3, 10%), and an incidental finding (n=6, 21%). Overt hemorrhage was detected in 7 patients (24%). There were 19 children (66%) with a single CM and 10 (34%) children with multiple CMs. In 7 cases with deep-seated CM, we used a TTRS to minimize retraction. In 9 cases which location of CM was at eloquent area, IONM was taken during surgery. There was no major morbidity or mortality after surgery. In the 29 operated children, the overall long-term results were satisfactory : 25 (86%) patients had no signs or symptoms associated with CMs, 3 had controllable seizures, and 1 had mild weakness.ConclusionWith the assistance of neuronavigation systems, intraoperative neuromonitoring, and TTRS, CMs could be targeted more accurately and excised more safely. Based on the satisfactory seizure outcome achieved, complete microsurgical excision in children is recommended for CMs presenting with seizures but removal of hemosiderin-stained areas seems to be unnecessary.

Minimally invasive thoracic decompression for multi-level thoracic pathologies

We describe our experience using a minimal access approach for multi-level dorsal decompression of the thoracic spine that may limit approach-related soft-tissue injury and spinal destabilization. Additionally, three patients, each with unique compressive thoracic pathology, are discussed. A single minimal access technique, using multi-level hemilaminotomies, was used to address these unique pathologies via a similar approach. The three patients in this study had a mean age of 49.3years (range: 45–55years), mean estimated blood loss of 750cc (range: 350–1000cc), mean operative time of 3.8hours (range: 3–5hours), and a mean post-operative hospital stay of 2.3days (range: 2–3days). Complete decompression was achieved with resolution of symptoms in all patients. Long-term follow-up averaged 26.7months (range: 15–36months). Radiographic decompression was demonstrated in all patients. Minimal access techniques using muscle-splitting tubular retractor systems can effectively treat multi-level dorsal compression of the thoracic cord, while potentially limiting morbidity and long-term spinal instability.

Minimally invasive approach for the treatment of intradural spinal pathology

A wide variety of spinal intradural pathology traditionally has been treated from a midline posterior laminectomy using standard microsurgical techniques. This approach has been successful in treating the pathology; however, it carries a risk of postoperative complications including CSF leakage, wound infection, and spinal instability. The authors describe a minimally invasive surgical (MIS) approach to treating spinal intradural pathology with a low rate of postoperative complications. Through a retrospective review of a prospectively collected surgical database, the authors identified 26 patients who underwent 27 surgeries via an MIS approach for intradural pathology of the spine. Using a tubular retractor system and an operative microscope, the authors were able to treat all patients with a unilateral, paramedian, and muscle-splitting technique. They then collected data regarding operative blood loss, length of stay, imaging characteristics, and outcomes. Eight cervical, 8 thoracic, and 11 lumbar intradural pathological entities, which included 14 oncological lesions, 4 Chiari I malformations, 4 arachnoid cysts, 3 tethered cords, 1 syrinx, and 1 chronic visceral pain, were treated via an MIS approach. The average blood loss was 197 ml and the average hospital stay was 3 days. One patient had to return to the operating room for noninfectious wound dehiscence. One patient required reoperation 18 months after the initial surgery for recurrence of the initial pathology. There was no CSF leak, no infection, and no spinal instability associated with the initial surgery on follow-up. Intradural spinal pathology can be safely and effectively treated with MIS approaches without an increased risk of neurological injury. This approach may also offer a reduced postoperative length of stay, risk of CSF leak, and risk of future spinal instability.

Does Minimally Invasive Surgery Have a Lower Risk of Surgical Site Infections Compared With Open Spinal Surgery?

Surgical site infection (SSI) ranges from 1.9% to 5.5% in most large series. Minimally invasive surgery (MIS) has been postulated to reduce SSI rates. (1) Is MIS associated with a lower incidence of SSI compared with open spinal surgery? (2) Are there other independent risk factors associated with SSI? (3) What bacteria are most common in spinal SSI? Medical records of 2299 patients who underwent transforaminal lumbar interbody fusion, laminectomy, or discectomy were analyzed and selected for a nested case-control analysis. Twenty-seven cases with SSI were matched with 162 control subjects without SSI stratified based on procedure performed within 28 days of the case's date of surgery. Patients were identified from an institutional database at a tertiary care hospital. MIS involved spinal procedures performed through a tubular retractor system. Univariate and multivariate analyses were performed. Patients undergoing open spinal surgery were 5.77 times more likely to develop SSI compared with MIS approaches (odds ratio [OR], 5.77; 95% confidence interval [CI], 1.0-32.7; p = 0.048). Also, from the multivariate regression model, diabetes (OR, 4.7; 95% CI, 1.3-17.0; p = 0.018), number of levels operated on (OR, 3.5; 95% CI, 1.6-7.5; p = 0.001), and body mass index (OR, 1.2; 95% CI, 1.0-1.3; p = 0.010) were predictive of an increased risk in SSI. Staphylococcus aureus was most frequently identified, being present in 12 of 21 (52.4%) patients in whom positive cultures were obtained. Four of the 12 patients had methicillin-resistant S aureus infection. In our series, MIS has a lower incidence of SSI. The risk factors predictive of SSI should be further evaluated in well-designed prospective trials. Level III, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

Minimally invasive unilateral approach for bilateral decompression of spinal stenosis and modified transforaminal lumbar interbody fusion for degenerative spondylolisthesis

This video describes a minimally invasive approach for treatment of symptomatic grade I spondylolisthesis and high-grade spinal stenosis. In this procedure, a unilateral approach for bilateral decompression is utilized in conjunction with a modified transforaminal lumbar interbody fusion and percutaneous pedicle screw fixation. The key steps in the procedure are outlined, and include positioning, fluoroscopic positioning/guidance, exposure with tubular retractor system, technique for ipsilateral and contra-lateral decompression, disc space preparation and interbody grafting, percutaneous pedicle screw and rod placement, and closure. The video can be found here: http://youtu.be/QTymO4Cu4B0.

Iatrogenic injury to the erector spinae during posterior lumbar spine surgery: underlying anatomical considerations, preventable root causes, and surgical tips and tricks

The approach-related morbidity resulting from iatrogenic erector spinae injury in posterior lumbar surgery has become an increasing concern for spine surgeons. Many studies have explained the injury mechanisms and reported new surgical approaches to prevent this iatrogenic injury from their own point of views, but there is still no systemic information for a thorough understanding of this iatrogenic erector spinae injury that may give spine surgeons practical advices in their individual operations. We consequently reviewed the literature on the anatomy of erector spinae, causes of injury, and relative minimally invasive approaches. We found that the local anatomic structures make the erector spinae vulnerable to injury during posterior lumbar surgery, especially the medial multifidus which is innervated only by the medial branch of the dorsal ramus, with no intersegmental nerve supply as in the other paraspinal muscles, and the injury factors mainly include dissection, retraction, denervation, and immobility. Studies suggest that the goal of prevention is to preserve the physiological structure of erector spinae and to avoid or limit the injury causes: approaches through spatium intermusculare and approaches with endoscope and tubular retractor system can prevent the erector spinae from injury by less dissection and retraction; non-fusion techniques may prevent the erector spinae from disuse atrophy by preserving the segmental motion and the adjacent erector spinae activity.

Minimal access to deep intracranial lesions using a serial dilatation technique

Surgical access to deep intracranial lesions causing the least amount of iatrogenic trauma to the surrounding brain tissue remains a challenging task. In this article, we evaluate the use of a set of sequential tubes that dilate and provide retraction of the overlying brain tissue acting as a surgical corridor for deep-seated brain lesions resection. In addition, we conducted a comprehensive review of the literature of previously described techniques using variable brain tubular retractor systems. We discuss the adaptation of a system designed for spinal use to intracranial pathologies and evaluate the outcomes for the patients involved in the study. Moreover, the advantages and limitations of the described technique were presented. Between August 2005 and 2011, a total of 30 patients with deep brain lesions were operated on using an incremental increase of tubing size for brain retraction guided by a frameless navigation device. Of these, seven cases were intraventricular, and 23 were intraparenchymal. Gross total resection was achieved in 70% of cases, and the remaining had planned subtotal resections due to involvement of an eloquent area. In conclusion, the technique of serial dilatation of the brain tissue can be used in conjunction with a microscope or endoscope to provide satisfactory access to deep intracranial pathologies. It appears to minimize the associated retraction injury to the surrounding tissue by gradually dilating the white fiber tracts. This operative approach may be considered as an effective and safe alternative for brain tumor resections in selected cases, especially deep-seated lesions.

Minimally invasive treatment of multilevel spinal epidural abscess

The use of minimally invasive tubular retractor microsurgery for treatment of multilevel spinal epidural abscess is described. This technique was used in 3 cases, and excellent results were achieved. The authors conclude that multilevel spinal epidural abscesses can be safely and effectively managed using microsurgery via a minimally invasive tubular retractor system.

To Screen or Not to Screen: Vertebral Artery Injuries in Blunt Cervical Spine Trauma

To present operative details and clinical follow-up of a series of patients with thoracic disk herniation treated with the minimally invasive technique of thoracic microendoscopic diskectomy (TMED).TMED was performed in 16 consecutive patients (age range, 18–79 years old) with 18 thoracic disk herniations. One patient with a calcified herniation in a direct ventral location was not included in this series. Patients were positioned prone, and a tubular retractor system was placed through a muscle dilating approach. The procedure was performed with endoscopic visualization. Outcomes were assessed using modified McNab criteria.There were no complications, and no case required conversion to an open procedure. The mean operative time was 153 minutes per level, and mean blood loss was 69 mL per level. Mean hospital stay was 21 hours. At a mean follow-up of 24 months (median, 22 months), 13 patients (81%) had excellent or good outcomes, 1 patient (6%) had a fair outcome, and 2 patients (13%) had poor outcomes. The two patients with poor outcomes had neurologic diagnoses (multiple sclerosis and multiple systems atrophy) that were ultimately found to be responsible for their symptoms and deficits.TMED is a safe and effective minimally invasive posterolateral approach for the treatment of thoracic disk herniations that lacks the morbidity associated with traditional approaches.

Minimally invasive tubular retractor system for adequate exposure during surgical obliteration of spinal dural arteriovenous fistulas with the aid of indocyanine green intraoperative angiography

Effective surgical obliteration of spinal dural arteriovenous fistulas (DAVFs) traditionally requires laminectomy or hemilaminectomy to allow intradural exposure and occlusion of the draining vein. The authors present successful treatment of a spinal DAVF by using a tubular retractor system to provide minimally invasive exposure at the L5-S1 level adequate for both microsurgical treatment and intraoperative indocyanine green angiography.

Lumbar Juxtafacet Cyst Resection

A retrospective review. To report our approach and results using a contralateral minimally invasive spinal surgical muscle splitting approach that allows visualization of the cyst without extensive removal of the adjacent facet joint. The use of tubular retractors for spinal surgery can potentially minimize tissue injury. Contralateral approaches may be beneficial in visualizing pathology that is located adjacent or under the facet joint. This approach has not been reported previously. Sixteen consecutive patients were treated using this approach using tubular retractors and the operating microscope. A retrospective chart and imaging review was conducted to determine operative and clinical measures. Subsequently, patients were contacted to obtain long-term clinical follow-up. Nine patients had an excellent and 5 had a good outcome, with median follow-up of 18 months, 2 patients were lost due to lack of follow-up. The mean operative time was 105 minutes and in all cases the blood loss was <40 mL. No postoperative instability was noted. A contralateral approach using a tubular retractor system provides excellent visualization of the facet cyst allowing safe cyst resection and nerve root decompression without compromising the facet joint. Larger case series with longer follow-up are needed to assess stability.

Minimally invasive lateral extracavitary corpectomy: cadaveric evaluation model and report of 3 clinical cases

In this paper, the authors' goal was to demonstrate the clinical and technical nuances of a minimally invasive lateral extracavitary approach (MI-LECA) for thoracic corpectomy and anterior column reconstruction. A cadaveric feasibility study and the subsequent application of this approach in 3 clinical cases are reported. Six procedures were completed in 3 human cadavers. Minimally invasive, extrapleural thoracic corpectomies were performed with the aid of a 24-mm tubular retraction system, using a posterolateral incision and an oblique approach angle. Fluoroscopy and postprocedural CT scanning, using 3D volumetric averaging software, was used to evaluate the degree of bone removal and decompression. Three clinical cases, including a T-11 burst fracture, a T-7 plasmacytoma, and a T4-5 vertebral body (VB) tuberculosis lesion, were treated using the approach. At 6 cadaveric levels, the mean circumferential volumetric decompression was 48% ± 16%, and the mean resection of the VB was 72% ± 13%. The mean change in anterior and posterior vertebral height with expansion of the corpectomy cage was 47 and 61 mm, respectively. There were no violations of the pleura or dura. Pedicle screw reliability was 95.8% (23 of 24 screws) with a single lateral breach. All 3 patients in the clinical cohort had excellent clinical outcomes. There was a single pleural tear requiring chest tube drainage. Operative images and a video clip are provided to illustrate the approach. A minimally invasive lateral extracavitary thoracic corpectomy has the ability to provided excellent spinal cord decompression and VB resection. The procedure can be completed safely and successfully with minimal blood loss and little associated morbidity. This approach has the potential to improve upon established traditional open corridors for posterolateral thoracic corpectomy.

Minimally Invasive Cervical Spine Foraminotomy and Lateral Mass Screw Placement

This technique article describes accomplishing multilevel posterior cervical decompression and lateral mass screw placement through a tubular retraction system. Multilevel foraminotomy and instrumented fusion using lateral mass screw fixation can be achieved through a minimally invasive technique using specialized retractors and intraoperative fluoroscopic imaging. Minimally invasive surgical techniques have been adapted to the cervical spine with good results. These techniques have the theoretical advantages of reducing morbidity, blood loss, perioperative pain, and length of hospital stay associated with conventional open posterior spinal exposure. Minimally invasive access to the posterior cervical spine was performed with exposure through a paramedian muscle-splitting approach. With the assistance of a specialized tubular retraction system with a deep soft tissue expansion mechanism, multilevel posterior cervical decompression and fusion can be accomplished. Minimized access to perform multilevel posterior cervical foraminotomy and fusion can be safely accomplished with tubular retraction systems. Complications associated with these techniques can include inadequate decompression, improper instrumentation placement, or neurologic injury due to poor access and visualization. Multilevel foraminotomy and instrumented fusion using lateral mass screw fixation can be safely achieved using these techniques. Complications associated with these strategies are typically due to inadequate visualization, incomplete decompression, or poor placement of instrumentation. As with all minimally invasive spine techniques, the surgeon must ensure that goals of the surgery, both technical and clinical outcomes, are comparable to those of a conventional open procedure.

Minimal Access Spine Surgery (MASS) for Decompression and Stabilization Performed as an Out-Patient Procedure for Metastatic Spinal Tumours Followed by Spine Stereotactic Body Radiotherapy (SBRT): First Report of Technique and Preliminary Outcomes

We report a novel approach in the treatment of spinal metastases with epidural disease and mechanical instability using a combined minimal access spine surgery (MASS) technique followed by spine stereotactic body radiotherapy (SBRT). This study was performed as a retrospective review of the first ten consecutive patients treated with this combined approach. The MASS technique was based on a tubular retraction system to gain access for decompression and mechanical stabilization achieved using methyl-methacrylate (MMA) applied under direct visualization. SBRT consisted of one to five image-guided high dose per fraction treatments. Eight patients were symptomatic at baseline. Pain, disability, and quality of life (QOL) were prospectively determined using the visual analogue score (VAS), Oswestry Disability Index (ODI), and Short-Form-36 version 2, respectively. The median follow-up was 13 months (range, 3-18). MASS successfully decompressed each patient. The median blood loss was 335 ml. Following MASS, the median time to SBRT treatment planning was 6.5 days and subsequent median time to treatment was 7 days. Local control was observed in 7 of the 10 patients. Improvements in VAS, ODI and QOL were observed post-SBRT. We report preliminary efficacy for our MASS-SBRT combined approach for patients with spinal metastases, mechanical pain and epidural disease.

Minimally invasive microsurgical resection of primary, intradural spinal tumours using a tubular retraction system

Study design. This is a retrospective review of prospectively collected data. Background. Primary, intradural spinal tumours have traditionally been microsurgically resected following macrosurgical laminectomy or laminoplasty. We hypothesize that approach-related morbidity can be reducedwith less-invasive approaches; we have therefore implemented a minimally invasive approach, with the assistance of a tubular retraction system, for microsurgical resection of primary intradural spinal tumours. Methods. From January 2007 to December 2009, 54 patients underwent surgery for a spinal intradural tumour. Of these, nine patients who underwent minimally invasive posterior unilateral transmuscular surgery using a tubular retraction system were included in this study. Resection grade and surgery-related complications were retrospectively reviewed. Results. All tumours were totally resected (verified by postoperative magnetic resonance imaging). There were no post-operative complications. Eight of the nine patients were mobilized on the day of surgery or on post-operative day 1. One patient was mobilized on post-operative day 2. Conclusions. Selected primary, intradural spinal tumours can be safely and successfully resected using a minimally invasive posterior unilateral transmuscular approach with the assistance of a tubular retraction system.

Minimal Invasive Decompression for Lumbar Spinal Stenosis

Lumbar spinal stenosis is a common condition in elderly patients and may lead to progressive back and leg pain, muscular weakness, sensory disturbance, and/or problems with ambulation. Multiple studies suggest that surgical decompression is an effective therapy for patients with symptomatic lumbar stenosis. Although traditional lumbar decompression is a time-honored procedure, minimally invasive procedures are now available which can achieve the goals of decompression with less bleeding, smaller incisions, and quicker patient recovery. This paper will review the technique of performing ipsilateral and bilateral decompressions using a tubular retractor system and microscope.

Minimally Invasive Removal of an Intradural Cervical Tumor : Assessment of a Combined Split-Spinous Laminectomy and Quadrant Tube Retractor System Technique

Conventional laminectomy is the most popular technique for the complete removal of intradural spinal tumors. In particular, the central portion intramedullary tumor and large intradural extramedullary tumor often require a total laminectomy for the midline myelotomy, sufficient decompression, and adequate visualization. However, this technique has the disadvantages of a wide incision, extensive periosteal muscle dissection, and bony structural injury. Recently, split-spinous laminectomy and tubular retractor systems were found to decrease postoperative muscle injuries, skin incision size and discomfort. The combined technique of split-spinous laminectomy, using a quadrant tube retractor system allows for an excellent exposure of the tumor with minimal trauma of the surrounding tissue. We propose that this technique offers possible advantages over the traditional open tumor removal of the intradural spinal cord tumors, which covers one or two cervical levels and requires a total laminectomy.

Comparative Study of the Outcomes of Percutaneous Endoscopic Lumbar Discectomy and Microscopic Lumbar Discectomy Using the Tubular Retractor System Based on the VAS, ODI, and SF-36.

ObjectivePercutaneous endoscopic lumbar discectomy (PELD) and microdiscectomy with the microscope endoscopic tubular retractor system(METRx-MD) are considered popular minimally invasive surgery (MIS) methods for the treatment of lumbar disc herniation. Many authors have also reported good clinical outcomes of these methods, but there are few comparative studies of them. This report compares the clinical outcomes of PELD and METRx-MD for lumbar disc herniation as MIS methods and discusses the efficacy of PELD.MethodsSeventy-two patients who had undergone single-level unilateral discectomy using two different methods, PELD and METRx-MD, between 2009 and 2011 were given a follow-up examination prospectively. Thirty-seven of these patients underwent discectomy using PELD, and the remaining 35 patients underwent discectomy using METRx-MD. In addition to the general parameters, clinical outcomes were assessed as specific parameters using the Visual Analogue Scale (VAS) score, the Oswestry Disability Index (ODI), the Short-form 36 (SF-36), and the return-to-work time.ResultsSixty-seven percent (25/37) of the patients in the PELD group and 74%(26/35) in the METRx-MD group were included in follow-up more than 6 months post-operatively. The mean improvements in the VAS scores for the back pain, leg pain, and ODI were 2.6, 4.8, and 30.1% for the PELD group and 2.8, 4.6, and 33.2% for the METRx-MD group, respectively. The SF-36 physical health component subscale score improved from 40.6 pre-operatively to 68.3 at the last follow-up for the PELD group post-operatively, and from 48.5 to 65.1 in the mental component subscale (METRx-MD group: from 34.4 to 66.5 and from 44.87 to 56.7). Complications occurred in 3/37 patients in the PELD group and in 2/35 patients in the METRx-MD group in the peri-operative period. The mean return-to-work times were 37.5 days in the PELD group and 42.5 days in the METRx-MD group.ConclusionThe outcomes for the PELD group are comparable to those for the METRx-MD group. It can thus be concluded that PELD for lumbar disk herniations may be performed safely and effectively. Also, PELD can be considered one of the treatment modalities of lumbar disk herniation.

Primary Closure of Inadvertent Durotomies Utilizing the U-Clip in Minimally Invasive Spinal Surgery

Retrospective clinical cohort study. To examine performance of the U-Clip for the closure of inadvertent durotomy occurring during minimally invasive spinal surgery. Primary closure of inadvertent durotomies that occur during minimally invasive spinal surgery can be technically difficult to accomplish when using standard knot-tying and suture management techniques, owing to the narrow and deep surgical corridor afforded by tubular retraction systems. The U-Clip is a novel device that can achieve tight tissue approximation without the need for knot-tying and excessive suture manipulation, making it ideally suited for use in minimally invasive spinal surgeries. We performed a retrospective review of patients who underwent minimally invasive decompressive procedures complicated by durotomy and repaired using U-Clips for the period January 2008 to January 2010. A total of seven patients were identified. Four of the seven patients were male. Six patients underwent lumbar laminectomy or discectomy. One patient underwent resection of a cervical synovial cyst. In each patient, the durotomy was repaired primarily using U-Clips. All six lumbar patients were discharged home on the same day, and the remaining patient was discharged the following morning. Mean follow-up was 6.3 months. No patient experienced symptoms related to persistent cerebrospinal fluid leakage. Primary closure of an inadvertent durotomy occurring during minimally invasive spinal surgery can be effectively achieved using the self-closing U-Clip device.