Navigating the learning curve of spinal endoscopy as an established traditionally trained spine surgeon.

BACKGROUND: Traditionally trained spine surgeons may want to transition from open spinal surgeries to endoscopic decompressions. The aspiring endoscopic spine surgeon may have to overcome multiple hurdles to master a learning curve without readily available training. Replacing traditional time-proven open spinal surgeries with endoscopic decompression may put the surgeons' reputation at risk and have an additional negative impact on his or her practice due to reduced revenue. The authors report on the utility of the mentor- and proctorship concepts to facilitate the transition from traditional open to endoscopic outpatient spine surgeries. METHODS: The study population (learning curve groups) was provided by two traditionally trained "apprentice" surgeons who have been in practice for 12 and 28 years, respectively. They trained with the remaining two authors under mentorship and proctorship arrangements. A VAS and Macnab outcomes analysis was performed by one surgeon laminectomy versus endoscopy in relationship to the case log representative of the initial learning curve. The second surgeon performed a postoperative narcotic utilization analysis as a representative way of favorable clinical outcomes in relation to his increasing case log with spinal endoscopy. RESULTS: The learning curve study by the first author (NA Ransom-under the proctorship program) consisted of 40 patients with 20 patients each divided into the traditional laminectomy control group and 20 patients in the endoscopic group. There were 22 females and 18 males with an average age of 57.38 years and a mean follow-up of 38.58 months. The preoperative VAS for patients in both groups was 7.95 compared to the postoperative VAS at final follow-up of 4.01 with a statistically significant postoperative VAS reduction (P<0.001) but without any significant difference between open laminectomy control- and endoscopic decompression groups. The endoscopic learning curve group outcomes improved significantly after 15 cases (P<0.048). The second author (S Gollogly-under mentorship program) performed a similar review of his surgical cases log and noted a significant reduction of postoperative narcotic utilization as a result of improved outcomes after an initial learning curve of 15 cases. Clinical outcomes for both authors showed improved Macnab outcomes in the majority of patients (NA Ransom =65%; S Gollogly =57%) with a slightly higher success rate in the laminectomy group (70%) versus the endoscopy group (65%) at a statistical significant level (P=0.036). CONCLUSIONS: The mentorship and proctorship approach is useful in helping traditionally trained spine surgeons to integrate spinal endoscopy into their well-established spine practices. Under the close guidance of an endoscopic master spine surgeon, the endoscopic learning curve may be comprehended by the experienced traditionally trained spine surgeon in approximately 15 lumbar decompression cases. During this initial 15-case learning curve, clinical outcomes with endoscopy may be slightly inferior to open laminectomy but may ultimately improve to equivalent levels.

Developing a sustainable hip service in Cambodia.

OBJECTIVE: Initial report on establishment of a hip service in Phnom Penh, Cambodia at Children's Surgical Centre. We describe indications for total hip replacement (THR) and initial results. METHODS: A database was established to collect data and track patients for follow up. Initial data collected included; diagnosis, implant used, post-operative complications. As the service developed, pre- and postoperative Harris hip scores were included. RESULTS: High rate of avascular necrosis (AVN) as the initial diagnosis. Five years post initiation of the hip service, 95 patients have received 116 THRs; including 10 revisions, 12 bilateral procedures. Complications/failures requiring revision involved four prosthetic femoral neck fractures, two aseptic acetabular component, two late infections, one instability. One failure, a periprosthetic acetabular fracture, required removal of all prosthetics. Complications not requiring revision, included three post-op foot drops, three superficial wound infections, one Vancouver B1 periprosthetic femur fracture. Average age was 41. Overall implant survival is 85% at three years. DISCUSSION: AVN was the most common indication for THR: many patients had a history of hip trauma, and/or prolonged steroids from traditional healers for pain. Problems with specific implants were addressed by the company. A different stem is now routinely used, no further fractures have been reported. Acetabular loosening, thought to be due to poor technique, has been addressed by focused training. Infection rate is monitored, and microbiology resources are improving. CONCLUSION: Developing an affordable hip arthroplasty service in a country like Cambodia is challenging. Developing a local registry has helped to identify complications and modify techniques.

Sagittal alignment of the spine and pelvis in the presence of L5-s1 isthmic lysis and low-grade spondylolisthesis.

STUDY DESIGN: A radiographic study of 82 patients with L5-S1 spondylolysis or spondylolisthesis of less than 50% displacement of L5 on S1. OBJECTIVE: To measure and describe the sagittal alignment of the spine and pelvis in patients with spondylolysis before the development of a large secondary deformity associated with progression of the spondylolisthesis. SUMMARY OF BACKGROUND DATA: Several publications have addressed the alignment of the spine and pelvis as an important factor in the occurrence, symptomatology, progression, and treatment of spondylolysis and spondylolisthesis. To our knowledge, this is the first report to systematically document the native sagittal alignment of affected patients and compare them to a large control population. MATERIALS AND METHODS: The sagittal alignment in this cohort of 82 patients was compared with a control population of 160 patients without symptoms of back pain or radiographic abnormalities of the spine and pelvis that was the subject of a previous study. RESULTS: Patients with spondylolysis and low-grade spondylolisthesis demonstrate increased pelvic incidence, increased lumbar lordosis, but less segmental extension between L5 and S1 than in a normal population. CONCLUSIONS: These data suggest that differences in the sagittal alignment of the spine and pelvis may influence the biomechanical environment that results in the development of spondylolysis and progressive spondylolisthesis.

Surgical fixation of pathologic fractures: an evaluation of evolving treatment methods.

The surgical techniques for the fixation of pathologic fractures continue to evolve. The present study examines clinical outcomes and complications associated with the use of newer generation interlocked intramedullary nails compared with open reduction and internal fixation with plates and screws for pathologic fractures in long bones. Fifty operative procedures performed on 37 patients by five community orthopaedic surgeons were retrospectively reviewed. The operative procedures were separated into two groups based upon the method of fracture fixation; the groups were compared for differences in hardware or fixation failure. The use of intramedullary devices was associated with a significantly lower number of hardware or fixation failures (p < 0.02). This data, in addition to several additional advantages of indirect reduction and intramedullary fixation of pathologic fractures, supports this method of fracture care over open reduction and internal fixation in appropriate cases.

The vertical projection of the sum of the ground reactive forces of a standing patient is not the same as the C7 plumb line: a radiographic study of the sagittal alignment of 153 asymptomatic volunteers.

STUDY DESIGN: A radiographic study of 153 normal volunteers. OBJECTIVES: 1) To test the hypothesis that the vertical projection of the sum of the ground reactive forces of a standing patient is located in the same place in the sagittal plane as the C7 plumb line; 2) to determine if there are consistent geometric relationships between the location of the top of the spine and the pelvis in the sagittal plane that occur in individuals without symptoms of back pain or radiographic evidence of deformity. SUMMARY OF BACKGROUND DATA: Defining the optimal state of spinal balance is difficult. A full understanding of the compensatory relationships between the spine, pelvis, and lower limbs remains elusive. METHODS: A total of 153 normal volunteers were subjected to radiographic examination using a digital force plate, a stabilized standing position, a standardized radiographic technique, and the computerized measurement of sagittal alignment. RESULTS: 1) The C7 plumb line and the gravity line in a stabilized standing position are not located in the same place; 2) the association between the center of T1 and the sacral endplate may be an anatomic constant and a marker of spinal balance in individuals without symptoms of back pain or radiographic evidence of deformity, and is determined by the formula 99 degrees - 0.1 degrees (sacral slope). CONCLUSIONS: We speculate that this information will be very helpful in evaluating symptomatic spinal disease in the context of the overall alignment of the spine and pelvis.

The radiographic results and neurologic complications of instrumented reduction and fusion of high-grade spondylolisthesis without decompression of the neural elements: a retrospective review of 44 patients.

STUDY DESIGN: A retrospective review of all cases of high-grade spondylolisthesis treated by 1 surgeon between the years 1991 and 2003. OBJECTIVE: To report the radiographic results and neurologic complications following instrumented posterior reduction and fusion without decompression of the neural elements. SUMMARY OF BACKGROUND DATA: Despite a large number of published reviews of the clinical results of operative intervention, controversy remains about the surgical treatment of high-grade spondylolisthesis. METHODS: A retrospective review of the clinical charts and radiographs of all patients with L5-S1 spondylolisthesis and more than 50% anterior displacement of L5 on S1 who were treated by the same surgical team at 1 institution. RESULTS: With this technique, an average reduction in the displacement of L5 on S1 from 64% to 38% was achieved. At a minimum 2-year follow-up (41 patients), we have detected 5 cases with evidence of pseudarthrosis or loss of reduction (11.4%). Overall, a neurologic complication rate of 9.1% occurred in this series, with a 2.3% chance of a persistent motor deficit. We did not detect any loss of bowel or bladder function after surgery. At last follow-up, and after revision procedures, we were able to achieve good or fair clinical results in 40 (90.9%) of 44 patients. CONCLUSIONS: These data suggest that a posterior instrumented reduction and fusion of high-grade spondylolisthesis without decompression of the neural elements can be accomplished with acceptable radiographic and clinical results.

Simultaneous anterior-posterior approach through a costotransversectomy for the treatment of congenital kyphosis and acquired kyphoscoliotic deformities.

BACKGROUND: Congenital kyphosis and acquired kyphoscoliotic deformities are uncommon but are potentially serious because of the risk of progressive deformity and possible paraplegia with growth. Our current approach for the treatment of these deformities is to use a single posterior incision and costotransversectomy to provide access for simultaneous anterior and posterior resection of a hemivertebra or spinal osteotomy, followed by anterior and/or posterior instrumentation and arthrodesis. To our knowledge, this approach has not been reported previously. METHODS: The medical records and radiographs for sixteen patients who had been managed at our institution for the treatment of congenital kyphosis and acquired kyphoscoliosis between 1988 and 2002 were analyzed. The mean age at the time of surgery was twelve years. The diagnosis was congenital kyphosis for fourteen patients and acquired kyphoscoliotic deformities following failed previous surgery for two. The mean preoperative kyphotic deformity was 65 degrees (range, 25 degrees to 160 degrees ), and the mean scoliotic deformity was 47 degrees (range, 7 degrees to 160 degrees ). Fifteen patients were managed with vertebral resection or osteotomy through a single posterior approach and costotransversectomy, anterior and posterior arthrodesis, and posterior segmental spinal instrumentation. The other patient was too small for spinal instrumentation at the time of vertebral resection. A simplified outcome score was created to evaluate the results. RESULTS: The mean duration of follow-up was 60.1 months. The mean correction of the major kyphotic deformity was 31 degrees (range, 0 degrees to 82 degrees ), and the mean correction of the major scoliotic deformity was 25 degrees (range, 0 degrees to 68 degrees ). Complications occurred in four patients; the complications included failure of posterior fixation requiring revision (one patient), lower extremity dysesthesias (one patient), and late progressive pelvic obliquity caudad to the fusion (two patients). The outcome, which was determined with use of a simplified outcomes score on the basis of patient satisfaction, was rated as satisfactory for thirteen patients, fair for two patients, and poor for one patient. CONCLUSIONS: A simultaneous anterior and posterior approach through a costotransversectomy is a challenging but safe, versatile, and effective approach for the treatment of complex kyphotic deformities of the thoracic spine, and it minimizes the risk of neurologic injury. LEVEL OF EVIDENCE: Therapeutic Level IV.

Results of preoperative pulmonary function testing of adolescents with idiopathic scoliosis. A study of six hundred and thirty-one patients.

BACKGROUND: Previous research has suggested a correlation between pulmonary impairment and thoracic spinal deformity. The curve magnitude, number of involved vertebrae, curve location, and decrease in thoracic kyphosis independently contribute to pulmonary impairment, but the strength of these associations has been variable. The objectives of this study were to test the hypothesis that increased thoracic deformity is associated with decreased pulmonary function and to determine which, if any, radiographic measurements of deformity predict pulmonary impairment. METHODS: Preoperative pulmonary function testing and radiographic examination were performed on 631 patients with adolescent idiopathic scoliosis. Correlation analysis and subsequent stepwise multiple regression analysis were carried out to assess the associations between radiographic measurements of deformity and the results of pulmonary function testing. RESULTS: The magnitude of the thoracic curve, the number of vertebrae involved in the thoracic curve, the thoracic hypokyphosis, and coronal imbalance had a minimal but significant effect on pulmonary function. While these four factors were associated with an increased risk of moderate or severe pulmonary impairment, they explained only 19.7%, 18.0%, and 8.8% of the observed variability in forced vital capacity, forced expiratory volume in one second, and total lung capacity, respectively. The degrees of scoliosis that were associated with clinically relevant decreases in pulmonary function were much smaller than previously described, but the majority of the observed variability in pulmonary function was not explained by the radiographic characteristics of the deformity. CONCLUSIONS: Some patients with adolescent idiopathic scoliosis may have clinically relevant pulmonary impairment that is out of proportion with the severity of the scoliosis, and this may alter the decision-making process regarding which fusion technique will produce an acceptable clinical result with the least additional effect on pulmonary function.

Classification of the normal variation in the sagittal alignment of the human lumbar spine and pelvis in the standing position.

STUDY DESIGN: A prospective radiographic study of 160 volunteers without symptoms of spinal disease was conducted. OBJECTIVES: The objective of this study was to describe, quantify, and classify common variations in the sagittal alignment of the spine, sacrum, and pelvis. SUMMARY OF BACKGROUND DATA: Previous publications have documented the high degree of variability in the sagittal alignment of the spine. Other studies have suggested that specific changes in alignment and the characteristics of the lumbar lordosis are responsible for degenerative changes and symptomatic back pain. METHODS: In the course of this study, anteroposterior and lateral radiographs of 160 volunteers in a standardized standing position were taken. A custom computer application was used to analyze the alignment of the spine and pelvis on the lateral radiographs. A four-part classification scheme of sagittal morphology was used to classify each patient. RESULTS: Reciprocal relationships between the orientation of the sacrum, the sacral slope, the pelvic incidence, and the characteristics of the lumbar lordosis were evident. The global lordotic curvature, lordosis tilt angle, position of the apex, and number or lordotic vertebrae were determined by the angle of the superior endplate of S1 with respect to the horizontal axis. CONCLUSIONS: Understanding the patterns of variation in sagittal alignment may help to discover the association between spinal balance and the development of degenerative changes in the spine.

The volume of lung parenchyma as a function of age: a review of 1050 normal CT scans of the chest with three-dimensional volumetric reconstruction of the pulmonary system.

STUDY DESIGN: An Institutional Review Board-approved retrospective review of 3400 sequential CT scans of the thorax obtained at a single institution over a 3-year period from 2000 to 2003 was performed. OBJECTIVES: We determined values for the volume of the right lung, left lung, and total lung volume and plot these data as a function of age and sex. SUMMARY OF BACKGROUND DATA: To our knowledge, no normative data on CT determined lung volume as a function of age have been published. METHODS: All examinations with a report of a normal CT scan of the chest (1050 examinations) were identified. The volume of lung parenchyma in each normal examination was determined by performing a three-dimensional reconstruction of the pulmonary system. RESULTS: Predicted increases in pulmonary volume with age for the third to 97th percentiles of male and female children were calculated. CONCLUSIONS: Normal values for the volume of lung parenchyma as a function of age and sex increase the clinical utility of a standard CT scan of the thorax in evaluating children with complex spinal deformities. They are a useful adjunct to pulmonary function testing. These data can be used in the pre- and postoperative evaluation of patients who are at risk of thoracic insufficiency syndrome, particularly in patients younger than 5 years of age, when standard pulmonary function testing cannot be accomplished. The effects of nonoperative treatment, early spinal fusion, and new techniques for the fusionless management of spinal deformity on lung volume can be quantified and compared to normal values.

Three-dimensional MR imaging in the assessment of physeal growth arrest.

The purpose of this study is to describe an imaging method for identifying and characterising physeal growth arrest following physeal plate aggression. The authors describe the use of three-dimensional MRI performed with fat-suppressed three-dimensional spoiled gradient-recalled echo sequences followed by manual image reconstruction to create a 3D model of the physeal plate. This retrospective series reports the analysis of 33 bony physeal bridges in 28 children (mean age 10.5 years) with the use of fat-suppressed three-dimensional spoiled gradient-recalled echo imaging and 3D reconstructions from the source images. 3D reconstructions were obtained after the outlining was done manually on each source image. Files of all patients were reviewed for clinical data at the time of MRI, type of injury, age at MRI and bone bridge characteristics on reconstructions. Twenty-one (63%) of the 33 bridges were post-traumatic and were mostly situated in the lower extremities (19/21). The distal tibia was involved in 66% (14/21) of the cases. Bridges due to causes other than trauma were located in the lower extremities in 10/12 cases, and the distal femur represented 60% of these cases. Of the 28 patients, five presented with two bridges involving two different growth plates making a total of 33 physeal bone bars. The location and shape of each bridge was accurately identified in each patient, and in post-traumatic cases, 89% of bone bars were of Ogden type III (central) or I (peripheral). Reconstructions were obtained in 15 min and are easy to interpret. Volumes of the physeal bone bridge(s) and of the remaining normal physis were calculated. The bone bridging represented less than 1% to 47% of the total physeal plate volume. The precise shape and location of the bridge can be visualised on the 3D reconstructions. This information is useful in the surgical management of these deformities; as for the eight patients who underwent bone bar resection, an excellent correspondence was found by the treating surgeon between the MRI 3D model and the per-operative findings. Accurate 3D mapping obtained after manual reconstruction can also visualise very small physeal plates and bridges such as in cases of finger physeal disorders. MR imaging with fat-suppressed three-dimensional spoiled gradient-recalled echo sequences can be used to identify patterns of physeal growth arrest. 3D reconstructions can be obtained from the manual outlining of source images to provide an accurate representation of the bony bridge that can be a guide during surgical management.

Determining lung volume with three-dimensional reconstructions of CT scan data: A pilot study to evaluate the effects of expansion thoracoplasty on children with severe spinal deformities.

A retrospective review of a cohort of five patients who had been treated with a new technique for expansion thoracoplasty was performed. This study was designed to demonstrate that measurement of the volume of the lungs by three-dimensional reconstruction of CT scan data from children with complex spinal and thoracic deformities is a useful method for determining lung volumes in children who are too young to cooperate with pulmonary function testing. The authors' results indicate that lung volume by analysis of CT scan data is also a means of evaluating and quantifying the effects of expansion thoracoplasty. The authors were able to show that expansion thoracoplasty and stabilization with a titanium rib was able to increase the volume of lung parenchyma in the five patients in the study group by approximately 25% to 90% after surgical intervention.

Scoliosis associated with Chiari 1 malformations: the effect of suboccipital decompression on scoliosis curve progression: a preliminary study.

STUDY DESIGN: A retrospective review of the effect of suboccipital decompression and duraplasty on curve progression in 22 patients who presented with scoliosis, syringomyelia, and a Chiari 1 malformation. OBJECTIVES: To document the clinical characteristics of scoliosis in association with a Chiari 1 malformation, determine the effects of suboccipital decompression and duraplasty on scoliosis curve progression over time, and identify the clinical factors (age, gender, and curve characteristics) that may be associated with a clinical improvement in the scoliotic deformity after suboccipital decompression. SUMMARY OF BACKGROUND DATA: Prior publications have documented the clinical characteristics, signs, and symptoms of the Chiari 1 malformation. An association between Chiari 1 malformations, syringomyelia, and scoliosis has been recognized and reported. Several authors have also reported on the response of the scoliotic curve to Chiari 1 decompression, but the number of patients in these reports has been small. This cohort represents the largest number of patients to date (21) with Chiari 1 malformations, syringomyelia, and scoliosis who have been treated and followed over time in order to determine the effect of decompression on curve progression. METHODS: A retrospective case review of 85 patients, age 16 years or less, who underwent posterior fossa decompression for a Chiari 1 malformation between 1990 and November 2000. A subset of 7 males and 15 females (22 of 85 total patients) who initially presented with scoliosis and were then found to have a Chiari 1 malformation was selected from this larger cohort for further review. The orthopedic and neurosurgical charts, spinal radiographs, and magnetic resonance imaging scans were then reviewed for each of these patients. RESULTS: Twenty-one of the 22 patients who presented with scoliosis met the inclusion criteria of having a Chiari 1 malformation, scoliosis, and an unfused spine during the follow-up period after suboccipital decompression. One patient had a posterior spinal fusion before suboccipital decompression and was excluded from further review. CONCLUSIONS: Thirteen patients of the 21 study patients (62%) had curve improvement or stabilization during the follow-up period. Eight of 21 patients (38%) had curve progression. Closer analysis reveals that the age, gender, and initial size of the scoliotic curve influenced the results of suboccipital decompression on the behavior of the scoliosis. Specifically, 10 of 11 patients (91%) who were less than 10 years of age at the time of suboccipital decompression have had their curves improve or stay the same during follow-up. In contrast, 5 of 7 female patients (72%) older than 10 years old with a curve greater than 40 degrees before suboccipital decompression have either been fused or are awaiting fusion.

Anterior thoracolumbar instrumentation: stiffness and load sharing characteristics of plate and rod systems.

STUDY DESIGN: An in vitro biomechanical study using a thoracolumbar corpectomy model to compare load sharing capabilities and stiffnesses of six different anterior instrumentation systems (three rod styles and three plate styles) for stabilizing the thoracic and lumbar spine. OBJECTIVES: To evaluate the axial load sharing capabilities of the instrumentation in a thoracolumbar corpectomy model and to measure the bending stiffness of the anterior instrumentation systems for the axes of flexion-extension, lateral bending, and axial rotation with and without an anterior column graft in place. SUMMARY OF BACKGROUND DATA: Prior publications have analyzed biomechanical characteristics of many spinal instrumentation systems. These reports have compared anterior instrumentation systems with posterior instrumentation systems, in situ fusion techniques, intervertebral spacers, structural allograft and instrumentation, and combined anterior and posterior instrumentation. Other reports have published data on the biomechanical characteristics of typical anterior and posterior spinal instrumentation systems. However, there are no published reports that specifically compare the characteristics of anterior plate-style with anterior rod-style systems, or examining load sharing capabilities. METHODS: Six constructs of each of six instrumentation systems were mounted on simulated vertebral bodies. A custom four-axis spine simulator was used to apply independent flexion-extension, lateral bending, and axial rotation moments as well as axial compressive loads. Axial load sharing was measured through a range of applied axial loads from 50 N to 500 N with rotational moments maintained at 0 Nm. The bending stiffness of each construct was calculated in response to +/-5.0 Nm moments about each axis of rotation with a 50 N compressive axial load with a full-length corpectomy graft in place, simulating reconstruction of the anterior column, and with no graft in place, simulating catastrophic graft failure. Statistical significance was determined using an analysis of variance and Fisher PLSD post hoc test with an alpha