Anterior Procedures Research Articles

Development and clinical application of a thoracoscopy implantable plate frame for treatment of thoracolumbar fractures and instabilities

The evolution of endoscopic spinal approaches and the associated possibilities for stabilization of the anterior column demands a new generation of spinal implants. Of particular interest is the possibility to implant using an endoscopic approach and the ability to achieve real angular stability so that for a suitable injury pattern an exclusively anterior procedure can be carried out. Since November 1999, a new type of anterior plate, MACS TL, developed to meet minimally invasive clinical requirements, has been used in the Berufsgenossenschaftliche Unfallklinik in Murnau, Germany for treating the mid and lower thoracic and lumbar region. The following reports on the results of the first 100 procedures carried out over a period of 15 months, of which 93% were performed endoscopically. The results convey a trend toward anterior endoscopic treatment of injuries of the anterior column using an implant with angular stability. The results now available on healing after fusion indicate the favorable influence of the stability provided by the implants on the bone-healing rate.

MACS-TL polyaxial screw XL. A new concept for increasing stability of ventral spondylodesis in the presence of dorsal injuries

The influence of additional dorsal structure damage on anterior stabilization of thoracolumbar fracture is still unknown. Screw cement enhancement is a possibility to reinforce the stability of anterior instrumentation. A new anchorage system has been developed for fixation of anterior stabilization devices, adapted through geometric optimization and the possibility of optional additional cementation after screw insertion in cases of poor bone quality. Is this enhancement strong enough to support a single anterior procedure such as the thoracoscopic technique and still compensate for dorsal instability? A biomechanical in vitro study simulating an anterior corpectomy, strut grafting, and overbridging stabilization with a dorsal laminectomy as dorsal structure damage was performed, and the primary stability parameters were evaluated with and without screw cement enhancement. The additional cementation enhanced the primary stability of the anterior instrumentation and compensated for dorsal instability.

Spinal hydatid disease.

Review article on spinal involvement of hydatid disease. A better understanding of this rare but clinically challenging disease is intended. An overview of the epidemiology, pathogenesis, presentation and diagnosis of spinal hydatid disease is provided. Management problems and frequent pitfalls are discussed as well as current therapeutic options, results and outcome. Thirty-seven reports of spinal hydatid disease published between 1964 and 2000 were reviewed. Most of the reported cases of spinal hydatid disease presented with spinal cord compression syndrome. Due to the relative rarity of the problem the diagnosis was frequently made during surgery. Surgical intervention by decompressive laminectomy was the most frequent first management. Reports of anterior procedures as well as spinal stabilization exist. Intraoperative prophylaxis to reduce spillage as well as pharmacotherapy were usually instituted. Results of surgery were generally reported to be poor. Progressive neurological and mechanical deterioration over the years was the most frequently reported disease course. Anecdotal reports of alternative management strategies exist. Spinal hydatid disease should be considered in the differential diagnosis of spinal cord compression syndrome in endemic countries and sought after with imaging and serology. Treatment is based on surgical decompression. Despite therapy the disease frequently relapses with progressive destruction of the vertebral column and neurological deterioration. Retention of spinal stability is the major long term concern. Overall outcome is poor with few reports of disease-free long term survival.

Somatosensory evoked potential monitoring of lumbar pedicle screw placement for in situ posterior arthrodesis

Mukund Gudnanna, MD, Mark Eskenazi, MD, John A. Bendo, MD, Jeffrey M. Spivak, MD, Ronald Moskovich, MD, FRCS, New York, NY, USASomatosensory evoked potentials (SSEPs) are commonly used to monitor the spinal cord and nerve roots during operative procedures that put those structures at risk. The utility of SSEPs to evaluate cauda equina and nerve root function during posterior spinal arthrodesis with pedicular fixation for degenerative lumbar disease has been reported anecdotally. The actual success of SSEPs in providing accurate assessment of nerve root integrity remains controversial. This report is an institution-wide review of the use of SSEPs to monitor nerve function during 186 consecutive posterior lumbar spinal arthrodeses with pedicle screws for degenerative lumbar spinal disorders. We excluded patients who had anterior procedures, spondyloreduction or scoliosis correction performed as part of their operation. There were 76 male and 110 female patients. Five fellowship-trained spine surgeons placed a total of 888 pedicle screws. Sixty-five percent of the patients (121 of 186) had a principle preoperative diagnosis of spinal stenosis with degenerative spondylolisthesis. Other common diagnoses were isthmic spondylolisthesis (21 of 186,11%) and degenerative scoliosis (16 of 186, 9%). Ninety-three percent of the cases (173 of 186) involved decompressive laminectomy. Eight percent (14 of 186) had posterior interbody fusions. L4–L5 was the most commonly arthrodesed segment. All pedicle screws were placed without the assistance of fluoroscopy or stereotactic computer-assisted guidance. Screw position was evaluated intraoperatively with standard posteroanterior and lateral radiographs. Anesthetic agents compatible with SSEP monitoring were used in all patients. SSEP baseline readings were obtained in all patients in the operating room soon after induction of general anesthesia. An acute and sustained loss of 50% of the SSEP amplitude and/or increase by 10% of latency from baseline was considered to be pathologic. None of the 186 patients had these significant SSEP changes. There were, however, five patients with postoperative radiculopathies distinct from their preoperative presentations. Early postoperative plain radiographs and computerized axial tomography scans revealed malpositioned pedicle screws. Consequently, 8 of 888 pedicle screws (0.90%) were either revised or removed. All patients had partial or full recovery of their new deficits after revision surgery. We conclude that the use of SSEPs in evaluating pedicle screw placement during lumbar arthrodesis is limited. In this setting, if monitoring is required, alternative methods with greater sensitivity and efficacy should be explored.

LAPAROSCOPIC MANAGEMENT OF PARASTOMAL HERNIA IN TRANSILEAL URINARY DIVERSION

Parastomal hernia develops after ileostomy or colostomy in 10% to 50% of cases. 1,2 Long-term parietal defects after continent urinary diversion through an ileal or colonic conduit have not been well evaluated due to the lack of data and different methods of urinary diversion. Such hernias also require difficult therapeutic management. In fact, recurrence and postoperative infection have often been observed after parietal restoration by an anterior or local procedure.3 Therefore, Helal et al proposed parietal reconstruction by laparotomy associated with stomal transposition.4 Based on our experience with laparoscopic postoperative hernia repair using intraperitoneal mesh we report this procedure in a patient who presented with a noncontinent urinary diversion parastomal hernia.

Retroperitoneal lateral lumbar interbody fusion with titanium threaded fusion cages

Intertransverse arthrodesis in which instrumentation is placed is associated with an excellent fusion rate; however, treatment of patients with symptomatic nonunion presents a number of difficulties. Revision posterior and traditional anterior procedures are associated with methodological problems. For example, in the latter, manipulation of the major vessels from L-2 to L-4 may be undesirable. The authors describe a method for performing retroperitoneal lumbar interbody fusion (LIF) in which a threaded cage is placed from L-2 through L-5 via a lateral trajectory, and they also detail a novel technique for implanting a cage from L-5 to S-1 via an oblique trajectory. Although they present data obtained over a 2-year period in the study of 15 patients, the focus of this report is primarily on describing the surgical procedure. The lateral lumbar spine was exposed via a standard retroperitoneal approach. Using the anterior longitudinal ligament as a landmark, the L2-3 through L4-5 levels were fitted with instrumentation via a true lateral trajectory; the L5-S1 level was fitted with instrumentation via an oblique trajectory. A single cage was placed at each instrumented level. Fifteen symptomatic patients in whom previous lumbar fusion had failed underwent retroperitoneal LIF. Thirty-eight levels were fitted with instrumentation. There have been no instrumentation-related failures, and fusion has occurred at 37 levels during the 2-year postoperative period. The use of retroperitoneal LIF in which threaded fusion cages are used avoids the technical difficulties associated with repeated posterior procedures. In addition, it allows L2-S1 instrumentation to be placed anteriorly via a single surgical approach. This construct has been shown to be biomechanically sound in animal models, and it appears to be a useful alternative for the management of failed multilevel intertransverse arthrodesis.

Laryngotracheal reconstruction with thyroid cartilage grafting

A technique to surgically manage neonatal subglottic stenosis is described in this report. Our extubation and decannulation rate in 17 patients who have undergone this procedure has been higher than that with the anterior cricoid split procedure. Early accidental extubation has not been problematic; this complication has been a difficulty with the anterior cricoid split procedure. The indications of this technique are being expanded to address subglottic pathology in olden children and for posterior cricoid augmentation.

Special considerations in therapy of injuries of the cervical spine in ankylosing spondylitis (Bechterew disease)

Cervical spine changed by Bechterew's disease is severely endangered with any increased load. Even decent trauma is enough to produce a fracture with affection of spinal cord. Because of little knowledge in these special items, late diagnosis of overlooked injury is not rare, especially in two-level injuries. Neurolesions following secondary fracture dislocations may occur ("fatal pause"). From january 1990 to february 2000 12 patients underwent surgery (dorsoventral stabilisation, ventral stabilisation, laminectomy). Diagnostic procedures, levels of injury, pre- and postoperative neurostatus (following Frankel's score), operative technique, typical complications and follow-up (Ø 17.8 months) were analyzed and compared with the literature. 11 patients showed preoperative neurodeficits. They were better in five cases and disappeared at all in another five cases after surgery (83% positive neurological outcome). There was no increase of neurology failure. Two patients died (ARDS and cerebral ischemia with destruction of vertebral arteries). One patient had to be reoperated because of implant dislocation. MRI is obvious in diagnostic for these lesions. There is also an absolute need for total (both clinical and radiological) examination of the whole spinal column, because there is often injury of more than one level (three times in our study). Therapy should be operative (dorsoventral stabilisation, in certain cases only anterior procedure or laminectomy). Late diagnosis and therapy with secondary worsening after fracture dislocation is not rare because of "overlooked injury". There were four patients, that would not have suffered cervical spine fracture (minimal injury force) without Bechterew's changes. There is often pulmonary failure through limitation of thoracic movement and cerebral ischemia following rupture of vertebral arteries as typical complications. Mortality (2 cases; 16%) in our collective is less than literature's medium rates (35-57%).

転移性脊椎腫ように対する手術成績

We evaluated postoperative results in fifteen patients with metastatic spinal tumor who underwent surgical treatment between 1989 and 2000. There were eleven males and four females with a mean age of sixty-four years (range: forty-eight to seventy-seven). The primary tumor was prostate cancer in five, lung cancer in four patients, etc. The level of spinal metastases was cervical in three and thoracic spine in eleven. We treated the patients surgically with anterior procedure in three and posterior procedure in twelve. For fixation, spinal instrumentation was employed in five patients.As a result, five of the fifteen patients recovered from their paralysis and twelve of fifteen patients attained pain relief. The rate of survivl was 42.9 percent at three months, 30.8 percent at six months, and 23.1 percent at one year.Surgical treatment for spinal metastases is effecticve for improving the quality of life in patients with severe pain of progressive paralysis. However, the indication of surgical treatment for spinal metastases must be determined carefully, taking into consideration their general condition, variety of primary cancer, and prognosis of each patient.

Monitoring In Vivo Implant Loads With a Telemeterized Internal Spinal Fixation Device

Implant loads were measured in 10 patients using telemeterized internal spinal fixation devices. To determine the postoperative temporal course of implant loads. Little information exists regarding the temporal course of loads on internal spinal fixation devices. The telemeterized internal spinal fixator allows the measurement of three force components and three moments acting in the fixator. Implant loads were determined in up to 20 measuring sessions for different activities, including walking, standing, sitting, lying in the supine position, and lifting an extended leg while in the supine position. Implant loads often increased shortly after anterior interbody fusion was performed. Several patients retained the same high level even after fusion had taken place. This explains the reason why screw breakage sometimes occurs more than half a year after implantation. The time of fusion could not be pinpointed from the loading curves. The results show that fixators may be highly loaded even after fusion has occurred. A flexion bending moment acts on the implant even with the body in a relaxed lying position. This means that already shortly after the anterior procedure, the shape of the spine is not neutral and unloaded, but slightly deformed, which loads the fixators. Pedicle screw breakage more than half a year after insertion does not prove that anterior interbody fusion has not occurred.

Temporary instrumentation in dixlocations, subluxations and fractures of the lower cervical spine

The anterior interbody fusion with instrumentation seems to be the standard procedure in unstable traumatic lesions of the lower cervical spine. The goal of this study was to objective the outcome of patients, treated by only temporary stabilisation of the injured motion segment (without bone-graft fusion). Between 1990 and 1998 155 patients with traumatic lesions of the cervical spine were treated operatively, in 22 cases transfixation of the injured level without bone-graft application was performed, an implant-removal was carried out in 12 patients so long. Only patients were included into the study, who were less then 45 years old at trauma and who had no trauma related osseous or disc encrouchment of the spinal canal. Not included were patients with degenerative formations of the cervical spine at time of trauma. Until follow up all patients with implantat removal returned back to work in their former profession, 11 of 12 patients classified their result as excellent or good. No secondary instabilities or postraumatic disc prolapse were observed. Restmobility in flexion/extension of the injured level was demonstrated in 8 patients. The preservation of traumatized motion segments may reduce the incidence of degenerative alterations and hypermobilities in adjacent levels. The transfixation technique in anterior procedures leads to a reduced time of spinal exposure, complications as a result of spinal graft manipulation, pseudarthrosis or donor graft site problems are no more relevant.

Anterior dural laceration caused by thoracolumbar and lumbar burst fractures.

A retrospective review of the records of 60 patients with thoracolumbar and lumbar burst fractures was undertaken to document the incidence and evaluate the sequelae of dural injuries found during anterior procedures. In the entire series, six (10%) patients each had a preexisting vertically oriented dural tear. All patients with anterior dural lacerations were male and had associated neurologic deficits. In all six patients, preoperative computed tomography showed an asymmetrically retropulsed bone fragment. Dural tears were repaired primarily. A postoperative cerebrospinal fluid leak developed into the chest cavity of one patient, who was treated successfully with subarachnoid drainage. In patients with anterior dural laceration, primary repair is warranted and can be performed more easily after intraoperative correction of kyphosis. Subarachnoid drainage may be effective in cases of continued postoperative anterior cerebrospinal fluid leakage before repeated operation is considered.

Iatrogenic lumbar spondylolisthesis: treatment by anterior fibular and iliac arthrodesis.

A retrospective independent radiographic and chart review was undertaken for 17 patients who underwent a unique anterior salvage procedure for iatrogenic and progressive postoperative spondylolisthesis. This one-stage anterior transabdominal discectomy, reduction, stabilization, and arthrodesis was first performed in 1979. Of the 17 patients, all complained of leg pain, 14 of back pain, 11 had neurogenic claudication, and 2 were bedridden preoperatively because of their pain. Of the 17 patients, 7 had no neurologic deficits, 2 had cauda equina syndrome, and the remaining 8 had motor root deficits. The average number of posterior operations before our salvage procedure was 1.8, with a range of 1 to 3. Eight patients had an average of 1.6 attempts at posterior arthrodesis, with a range of 1 to 3 procedures. Two patients had a grade I spondylolisthesis, 11 a grade II, and 4 a grade III. Follow-up was available for 16 patients from 2 years and 3 months to 11 years and 5 months after the index operation (mean, 6 years and 5 months). One patient with severe cardiovascular disease died perioperatively. This anterior procedure was able to restore spinal stability and decompress the neural elements in 13 of 16 patients. Eleven obtained a solid arthrodesis. Three patients required further spinal surgery: two posterior fusions for symptomatic nonunions and one posterior foraminotomy for persistent foraminal stenosis. No patient deteriorated neurologically, the two with cauda equina syndrome recovered, and all but one patient with motor root deficits recovered fully. At latest follow-up, there were six excellent, seven good, and three fair results. There were no poor results. Although technically difficult and troubled by complications, the relative historical merits and principles of this unique anterior salvage procedure probably warrant further consideration, especially in light of evolving anterior surgical technologies.

Vertebral decancellation for severe scoliosis.

The results of staged surgery including vertebral decancellation were reviewed retrospectively for 21 patients with severe scoliosis. To evaluate the benefits and limitations of vertebral decancellation as new anterior surgical procedure. The curvatures of severe scoliosis are often very rigid, and surgical correction using the anterior or posterior approach may not achieve the desired correction. Some studies reported neurologic complications might appear due to the aggressive approach or excessive correction force. Twenty-one patients (average age, 17.0 years) with severe scoliosis, in whom Cobb angle was over 80 degrees (average angle, 107 degrees), underwent staged anterior and posterior spinal reconstruction. Vertebral decancellation was performed as anterior procedure, and until posterior instrumentation, halo traction was carried out. The transition of curvatures in coronal and sagittal planes was assessed in this series. The average correction rate of lateral curvature at the final follow-up was 46%. The average loss of correction was 2.5 degrees. Kyphosis, measured between T5 and T12, changed from 41 degrees to 36 degrees. Lordosis, measured between L1 and S1, changed from 56 degrees to 45 degrees. Transient neurologic deficit was seen in one case after vertebral decancellation. Staged surgery including vertebral decancellation is an effective surgical method for patients with severe scoliosis, where an inflexible rigid curve or the risk of occurrence of neurologic complications due to temporary correction may exist.

Complications of buttress plate stabilization of cervical corpectomy.

A retrospective analysis of 14 patients treated with cervical corpectomy and buttress plate fixation. To determine the complications of buttress plate fixation following multilevel cervical corpectomies. Buttress plate fixation of multilevel cervical corpectomy has recently been reported. Biomechanical data suggests that it is preferable to long plates spanning the entire corpectomy site. There are no clinical studies that have specifically addressed the complications of this type of plate fixation. The records and radiographs of all patients who had undergone cervical buttress plate fixation following anterior cervical corpectomy for myelopathy were independently reviewed. Twelve of the patients had three-level corpectomies and two had two-level corpectomies. All patients had placement of a short plate at the inferior end of the construct with sufficient overhang to act as a buttress against graft extrusion. Three patients underwent posterior cervical fusion in addition to the anterior procedure. Graft extrusion. One patient had complete graft extrusion on the third post-operative night. A second patient who had undergone circumferential fusion had minimal plate dislodgement secondary to graft settling. Pseudarthrosis. Three patients had pseudarthroses. Two of these required revision posterior surgery. Neurologic. None of the patients suffered neurologic complications. With the exception of the one patient who died, the rest of the patients all improved by at least one Nurick grade. The most catastrophic complication in the present series was plate dislodgement causing airway compromise and eventually resulting in death. Surgeons who utilize these types of buttress plates without additional posterior instrumentation should be aware of the potential complications of buttress plate fixation.

Urgent surgical stabilization of spinal fractures in polytrauma patients.

A prospective, longitudinal study of multiply injured patients treated with segmental instrumentation for spinal fractures with a minimum 2-year follow-up. To determine whether urgent stabilization of spinal fractures in severely injured patients increases the risk of surgery compared with early treatment and historical results. Opinion in clinical studies is divided about whether operative treatment offers an advantage over nonoperative treatment in isolated spine fractures. Concomitant trauma is rarely discussed relative to decision making or surgical timing. Urgent stabilization of long-bone fractures improves survival and outcome in polytrauma patients. To date, urgent treatment of spine fractures in polytrauma patients has not been considered in the literature. Seventy-five consecutive patients treated with segmental instrumentation for spinal trauma were observed prospectively to assess perioperative and longterm outcome. Twenty-seven patients with severe polytrauma (injury severity score, > 26) were separately analyzed. Perioperative and postoperative results were analyzed relative to timing of surgery, injury severity score, and surgical approach. Urgent treatment was defined as that provided within 24 hours of the spinal injury, and early treatment was defined as that provided between 24 and 72 hours after injury. Twenty-five patients (93%) sustained two or more major injuries in addition to the spine fracture, and 17 of 27 (63%) had neurologic injury. The mean injury severity score approached or exceeded the LD50 (50% expected mortality) in each group--36.0 for the early-treatment group and 42.0 for the urgent group--but only one patient in each group died. There were no deep venous thromboses, pulmonary emboli, neurologic injuries, decubiti, deep wound infections, or episodes of sepsis in either group. Blood loss for anterior procedures was significantly higher in the urgent group, but estimated blood loss for posterior procedures was similar for both groups. At 49 months' mean follow-up, no revisions were necessitated by the urgent spinal treatment. Urgent spinal stabilization is safe and appropriate in polytrauma patients when progressive neurologic deficit, thoracoabdominal trauma, or fracture instability increase the risks of delayed treatment.

Classification of thoracic and lumbar injuries: An analysis of interobserver reliability.

The purpose of a fracture classification is to help the surgeon to choose an appropriate method of treatment for each and every fracture occuring in a particular anatomical region. The classification tool should not only suggest a method of treatment, it should also provide the surgeon with a reasonably precise estimation of the outcome of that treatment. But to use a classification before its workability has been proved is inapproproiate and can lead to confusion and more conflicting results. Any classification system should be proved to be a workable tool before it is used in a discriminatory or predictive manner. The radiographs of fourteen fractures of the lumbar spine were used to assess the interobserver reliability of the AO classification system. The radiographs and CT scans were reviewed in twenty two hospitals experienced with spinal trauma. The mean interobserver agreement for all fourteen cases was found to be 67 % (41-91 %),when only the three main types (A, B, C) were used. The corresponding kappa value of the interobserver reliability showed a coefficient of 0,33 (range, 0,30 to 0,35). The reliability decreased by increasing the categories. For some injuries the interobserver reliability was found to be over 90 % and also for the recommended therapeutic procedure there was an acceptable agreement. But the decision between an posterior approach alone or an additionally anterior procedure seems to be the most important question in treatment of spinal injuries at that time.

Bilateral Adrenalectomy for Cushing's Syndrome. Anterior Versus Posterior Surgical Approach

OBJECTIVE: This study evaluates the intraoperative and postoperative complications in patients with Cushing's syndrome who underwent bilateral adrenalectomy comparing the posterior or anterior operative approach. BACKGROUND: The posterior approach for bilateral adrenalectomy has been advocated over the anterior approach because of rapid recovery and decreased morbidity, but the long-term complications associated with each procedure are not well described. METHODS: The intraoperative profiles and morbidity in 48 patients undergoing bilateral adrenalectomy for Cushing's disease through either the anterior or posterior approach from 1985 to the present were reviewed comparing the intraoperative complication and early and late postoperative complication rate and morbidity. RESULTS: Twenty-seven patients underwent an anterior transabdominal procedure, whereas 21 underwent a posterior retroperitoneal procedure via bilateral incisions. Age, weight, and diagnostic categories of Cushing's syndrome were similar between the two groups as well as serum cortisol and 24-hour urinary cortisol levels. Operative time, estimated blood loss, and transfusion requirements were not different between the groups, even though adrenal glands excised through the anterior approach were significantly larger. Acute morbidity was similar between the groups. However, 17 (81%) of 21 patients who underwent posterior bilateral adrenalectomy suffered from chronic back pain, compared with 2 (7%) of 27 via the anterior approach. Five of these patients in the posterior group considered the pain incapacitating, and the mean time to return to work was significantly longer in the posterior group because of back pain. CONCLUSIONS: The anterior approach to bilateral adrenalectomy has comparable intraoperative complications and early morbidity compared to the posterior approach. The posterior approach has a very high incidence of chronic incision-related back pain. The anterior approach is the preferred open surgical technique in most patients undergoing bilateral adrenalectomy for Cushing's syndrome without other contraindications for undergoing laparotomy.

Video-assisted thoracoscopic surgery to the upper thoracic spine.

The standard open technique for exposure of the upper thoracic spine, T1-T4, usually requires a difficult thoracotomy. From November 1, 1995 to June 30, 1997, eight patients underwent video-assisted thoracoscopic spinal surgery in our institute to treat their upper thoracic spinal lesions endoscopically. A new approach, the so-called "extended manipulating channel method," was used in this series that allows the combined use of video-assisted thoracoscopy and conventional spinal instruments to enter the chest cavity freely for the procedures. Patients' ages ranged from 44 to 89 years (average, 60 years). Definitive diagnoses included two pyogenic spondylitis and six spinal metastases. Five patients presented initially with myelopathy. There were no deaths or neurologic injuries associated with this technique. The mean surgical time was 3.1 h. The mean duration of chest tube retention was 3.3 days. The mean total blood loss was 1,038 ml, and two patients had a blood loss of more than 2,000 ml owing to bleeding from epidural veins or raw osseous surfaces. Complications included one superficial wound infection and one subcutaneous emphysema that resolved spontaneously. In this series, there was no need of conversion to open thoracotomy for the patients. The thoracoscopy-assisted spinal technique using the extended manipulating channels, usually 2.5-3.5 cm, allows variable instrument angulations for manipulation. The mean surgical time (3.1 h) was considered no longer than for an open technique for the equivalent anterior procedure. Such an approach can achieve less procedure-related trauma and has proved to be a good alternative to other treatment modalities.

'Oh's Retractor': New adjustable retractor for anterior cervical approach

The purpose of this study is to describe the features and benefits of Oh's Retractor. Oh's Retractor is a new, easily adjustable instrument for anterior cervical approach procedures. It delivers improved stability, precision, and ease-of-use compared with currently available instruments. The major contribution of this invention is its radically new design which allows the surgeon to logically adjust the instrument step-bystep as needed during the procedure. The instrument provides both a wide range of maneuverability and fine-tuned precision. Existing retractors may present cumbersome and precarious conditions due primarily to difficulty in stabilizing the instrument for the operative field. In contrast, Oh's Retractor can be easily stabilized. This paper illustrates how Oh's Retractor optimizes surgical performance and saves time by providing the benefits of greater stability, precision, and ease of use. [Neurol Res 1999; 21: 45-47]