Abstract

With the increasing awareness in both the medical community, as well as the general public of the progressive nature of adult scoliosis, more patients with this condition are coming to the attention of the spinal surgeon. With recent technical developments, the surgical armamentarium currently available has certainly improved, yet these patients remain a challenging population of patients. Infantile, juvenile, and adolescent idiopathic scoliosis are defined by their age of presentation. Similarly, adult scoliosis is defined as a presentation of scoliosis after skeletal maturity. Yet most studies in the literature define adult scoliosis arbitrarily as scoliosis existing in a patient age 18 or older. The majority of these patients, therefore, have curves which have persisted through adolescence into adult life with etiologies which mirror those of a younger patient population. Degenerative scoliosis related to osteoporosis and iatrogenic causes are additional etiologies of deformity which more typically present in adult patients. The indications for treatment in the adult patient are similar to those in the adolescent: progression of the deformity, pain, deterioration of pulmonary function, and perhaps cosmesis. The complications encountered during the surgical management of these patients is quite high (50-80%) when compared to their adolescent counterparts. Complications include pseudoarthrosis, loss of lumbar lordosis, thromboembolic disease, instrumentation failure, neurologic deficits, and wound infections. Therefore, even with the recent advances in surgical technique the decision of whether or not to operate on a given patient remains the single most critical decision.

Abstract

Few areas of spinal surgery present a greater challenge than management of occipitocervical abnormalities. This is due to the simultaneous presence of two commanding, yet conflicting treatment principles. First, decompression and protection of the spinal cord at this level is synonymous with the presevation of life itself. Second, however, the degree of cervical movements at this junction is unprecendented in the spine, requiring the preservation movement yet stabilization of discrete motion segemnts. The interrelation of these two critical functions is realized in the complex arrangement of the Co- C1-C2 anatomic configuration. The occipitocervical junction is responsible for 50% of the 90 degrees of head rotation. In addition, 10-15 degrees of flexion and extension are added to the subaxial cervical spine by CO-C1-C2. This duality of function is the primary reasin for the complexity of the facet joints in this location. No lateral bending occurs at this level.

Abstract

Instrumentation techniques in the cervical spine were first described in 1891.15 Over 100 years have passed, and many surgeons have made contributions that now allow complicated operations to be performed with predictable results for many conditions affecting the cervical spine. The purpose of this chapter is to describe the currently acceptable techniques of instrumentation and fusion for the subaxial cervical spine. Because different devices are used, depending on whether the spine is approached from the front or from the back, this chapter is divided into those used through anterior and those used through posterior approaches. The decision to approach a given problem anteriorly or posteriorly depends on several factors including the location of the pathology, the nature of the underlying problem, the goals of the operation, and the experience of the surgeon.

Abstract

Low back pain is a large and increasing cause of workers compensation claims in all industrialized nations. In the United States, 23% of all compensation claims involved back pain. Almost 90% of these were self limiting sprains and strains. It has been estimated that the remaining 10% account for approximately 75% of lost work days, medical costs and permanent disability payments. It is the goal of the spine surgeon to provide the patient with relief from his symptoms and return him or her to the work place. Advances in lumbar skeletal fixation have increased the fusion rate, decreased hospital stay and immobilization and decreased morbidity associated with lumbar spinal fusions.

Abstract

Lumbar fusion success rates are unpredictable. Turner, reporting on 82 published studies, cites a fusion success rate that ranged from 16% to 93%, mean 66%. Spinal fusion can be compromised by a number of risk factors that have been identified which tend toward a poorer prognosis. These risk factors include smoking graft type (autograft vs. allograft), and number of fusion levels. Brown reports a statistically different, 32% decrease in spinal fusion healing in smokers as compared to nonsmokers. Allograft has been reported to significantly lower success rate in posterolateral fusions. Autograft is the preferred graft material because it is both tissue compatible and contains viable bone cells. If these bone cells can continue to be viable during the bridging process, the fusion healing process should be enhanced. Allograft bone does not have any viable bone cells within its matrix and may be rejected due to tissue incompatibility issues. Wilkinson reported that each additional fusion level decreased the possibility of spinal fusion success by approximately 20%. Surgeons are attempting various treatment regimens and adjunctive procedures to increase the odds of fusion for these high risk patients. One method is through the adjunctive use of electrical stimulation by pulsed electromagnetic fields (PEMFs) following a spinal fusion procedure. PEMFs is an inductive method of generating an electric potential at the fusion site. A pulsing magnetic field surrounding the fusion site through a dual coil system creates an electronegative potential along the fusion site. This negative potential is very similar to the natural property that bone has of healing itself. This technology has proven useful in treating the nonunion of long bone and it seemed reasonable to attempt to improve fusion success rates in spinal fusions given the relative safety of PEMFs and the success noted so far in long bones. The purpose of this paper is to demonstrate the safety and efficacy of PEMFs in treating spinal fusion patients with one or more high risk factors regardless of the presence/absence of fixation.

Abstract

History and development: as we continue to better define the true indications of surgical procedures and ultimately refine these procedures to improve their inherent morbidity, the development of spinal endoscopic techniques continue to enhance minimally invasive surgical procedures. Surgeons desire to define anatomy and to visualize pathology long preceded our ability to utilize sophisticated imaging techniques. Visualization tools using rod-lens technology have been employed for use in the intracranial and in the myeloscopic visualization of neuroanatomy. Pool in 1942 described a large series of myeloscopic inspections of intrathecal normal and abnormal anatomy. His classic diagrams display the presence of disc herniations, arachnoiditis, and spinal stenosis from intrathecal inspections performed through a large bore myeloscope (Figure I). The continued evolution of myeloscopy was thought to be essential for the treatment of arachnoiditis, large herniated disc disease, and intrathecal tumor pathology. Its complications, however, led to its disuse because of the large bore scope requirements and the morbidity required to insert this instrumentation in the appropriate neural cavity.

Abstract

Economic and cunical factors have placed an increasing emphasis on minimally invasive surgical treatment of lumbar disc herniations. Percutaneous posterolateral techniques have been used increasingly over the last seven years but have definite technical limitations related to location of the disc herniation and its size. Dissatisfaction with percutaneous posterolateral lumbar discectomy (PPLD)led the senior author to explore the possibility of an anterior approach. Preliminary work included a "hands on" laparoscopy course and assisting experienced laparoscopists in the operating room. Before authorization from the Palomar Medical Center Investigational Review Board was obtained, dissection of the prevertebral space was performed in a human volunteer and a two level discectomy on a recently deceased patient was carried out in the operating room. The first operation was performed on February 4, 1991. Early in the series, patient selection was identical to that of percutaneous posterolateral discectomy, namely a soft posterolateral herniation contained within the posterior longitudinal ligament (PLL). As experience was gained, indications were expanded to include larger disc herniations. A description of the technique and our experience with the initial 21 consecutive cases form the basis of this report.

Abstract

Computer-driven robots and medical imaging technology may soon enable surgeons to plan and execute intricate procedures with unprecedented precision. Our experience in introducing a robotic system for use in an active role in cementless total hip replacement surgery has convinced us that the marriage of these two technologies - robotics and medical imaging - is likely to change the way many types of surgical procedures are performed. The ability to link an image-based preoperative plan with its surgical execution by a robot may be the key to improved outcomes. Research and development of robotic systems for a wide variety of medical applications is underway at a number of prestigious institutions. Grenoble University has developed the IGOR (Imaged Guided Operating Robot) system. This six-axis robot has performed more than 400 interventions, acting as a positioner for brain surgery in both biopsy and therapeutic procedures. AlephMed and Digital are currently assisting the developers in integrating image analysis into the system. Future development plans include an application for spinal surgery.

Abstract

Inorganic ceramic compounds have found increasing serviceability as implants in orthopedic surgery and can be classified into general categories using their chemical property characteristics. These characteristics include terms, such as inert, active, and degradable, that normally refer to the ceramics, time-dependent interactions on a relative basis, one-to-another, when implanted in hard and soft tissue sites. The early interest in the high grade (purity and strength) oxide ceramics of aluminum (alumina), titanium (titania), and zirconium (zirconia) was based on information from industrial applications in chemical processing of corrosive solutions. The selection of alumina for high surface area (porous) implants in bone was based partly upon the knowledge that these ceramic materials could maximally resist biodegradation phenomena, while being routinely available at reasonable costs.

Abstract

Total joint replacement arthroplasty has been extremely successful since its inception in the 1960's. There have been untoward problems however that have become more apparent with the current state of the art joint replacement. These problems include thigh pain following total hip replacement arthroplasty, proximal bone resorption as a result of stress shielding, and areas of bone lysis. The progressively enlarging size of the metal implant stem with its associated increased elastic modulus has been implicated in the above noted problems. The implant stem as well as metal alloy screws utilized to fix acetabular and tibial plate components to bone have been suggestedto contribute to particulate debris and the above noted problems through fretting. Bioresorbable polymers can be utilized as screws to fix the definitive implant to bone as well as utilized as a stem to allow rigid fixation of the implant until there is firm attachment, whether by mechanical or chemical bonding. When the definitive implant has been adequately attached to bone, the resorbable polymer degrades completely, thereby, obviating many of the problems seen with the presently retained screws and large, high modulus, intramedullary stems.

Abstract

Among surgical specialities; orthopedics has been the slowest to embrace the laser as a surgical tool. Although lasers have been used in ophthalmology for over two decades, and laser usage has become commonplace in gynecology, otorhinolaryngology, dermatology, plastic surgery, and general surgery, it is only within the past four years that lasers have attracted appreciable attention in orthopedics. The fact that much of the surgery in the majority of specialities is ablative in nature makes use of the laser particularly appealing, as lasers are the ultimate of ablative tools. Much of orthopedic surgery, on the other hand, is primarily reparative or reconstructive in nature. The re-establishment of continuity or the replacemeut of tissues such as bone, tendon, and ligament are the goals of the majority of orthopedic surgical procedures. While lasers may ultimately play some role in tissue repair, that role is currently viewed as one of providing precision (for example, nerve and small vessel "welding") rather than strength, the latter being crucial in orthopedics. It is, thus, not surprising that the interest in "orthopedic lasers" centers around the relatively few procedures that are ablative in nature - intervetebral disc removal, the removal of polymethylmethacrylate, and the majority of arthroscopic procedures.

Abstract

Arthroscopic techniques for shoulder arthroscopy have evolved and been refined constantly over the last decade. Significant advances have been made, compared to the first arthroscopic intraarticular examinations on cadavers by Takagi in 1918. Advances in fiberoptics, computer technology, and surgical instrumentation, coupled with innovative ideas and improved operative skills, have opened a new era in the orthopedic evaluation of intraarticular structures and treatment of pathology by the orthopedic surgeon. Arthroscopic examination of the glenohumeral joint and subacromial bursa permits the surgeon to visually assess, document, and treat shoulder pathology in an injury specific manner. Critical to effective use of this technology and skill is a comprehensive and reproducible system for thorough examination and documentation, so that no abnormality is inadvertently overlooked and treatments are effectively performed. In this fashion, standardization is developed for evaluating surgical treatments and providing a common base for professional communication and continued education within the orthopedic community. At the Southern California Orthopedic Institute, a comprehensive 15-point glenohumeral and 8-point subacromial examination from both posterior and anterior portals has been developed and is widely accepted in most arthroscopic forums. The operating room set-up, instrumentation, patient positioning, and the authors' preference for systematic glenohumeral arthroscopy and bursoscopy will be described. Specific methods for arthroscopic subacromial decompression, distal clavicle resection, and evaluation of the rotator cuff will be outlined. It is imperative that the surgeon have a complete knowledge of normal shoulder anatomy and common variants.

Abstract

The indications for performing arthroscopy of the hip are fewer than for the knee and shoulder. Yet, it is a very useful procedure when the occasion arises. The purpose of this article is to present a technique that is simple and safe. The lateral approach over the greater trochanter, not only meets these criteria, but it gives the surgeon enough maneuverability to completely visualize the joint and to perform surgery.

Abstract

While the use of external fixators is not revolutionary, the ilizarov apparatus has dramatically improved the application of the principles of external fixation to the management of bony defects, malunions, infections, and pseudarthroses. Since its formal introduction in Western Siberia in 1951 by Gavril Abramovich Ilizarov, an international cadre of surgeons has employed its methods to pioneer modern limb salvaging procedures. Such techniques are made possible by the numerous advantages, including immediate loading of the limb postoperatively, and the use of healthy viable bone to replace devascularized dead bone "in situ" by osteoclasis, localized transport and osteogenesis. Accordingly, leg length discrepancy, deformity and infected nonunions may all be treated effectively. The basic premise of the Ilizarov technique is that osteogenesis can occur at a surgical osteotomy site given the appropriate degree of retained vascularity, fixation and quantified distraction. This dogma is a function of many variables which Ilizarov classified into three categories; biological, clinical, and technical. First, biologic variables include preservation of endosteal and periosteal blood supply via corticotomy and stable fixation to prevent shear forces, but to permit axial dynamization with postoperative weightbearing. Distraction should occur at approximately 1 mm. per day divided into four times per day. At the termination of distraction, neutral fixation should be permitted to allow strengthening of the new bone. In essence, the technique fools the body into believing it is a child again. The corticotomy sites now act as physes.