Early experiences with video-assisted thoracoscopic surgery: our first 70 cases

The Thoracoscopic Approach in Spinal Cord Disease

Video-assisted thoracic surgery (VATS) has been growing in popularity over the past 2 decades as an alternative to open thoracotomy for the treatment of several spinal conditions, and in the field of minimally invasive surgery, it now acts as a keyhole to the thoracic spine.

MATERIALS AND METHODS

Most VATS approaches are from the right side for pathologies involving the middle and upper thoracic spine because there is a greater working spinal surface area lateral to the azygos vein than that lateral to the aorta. Below T-9, a left-sided approach is made possible because the aorta moves away from the left posterolateral aspect of the spine to an anterior position as it passes through the diaphragm.

RESULTS

VATS has been used extensively in spinal deformities such as scoliosis. The use of VATS in spine surgery includes the treatment of thoracic prolapsed disk diseases, vertebral osteomyelitis, fracture management, vertebral interbody fusion, tissue biopsy, anterior spinal release, and fusion without or with instrumentation (VAT-I) for spinal deformity correction. As the knowledge and the comfort of using such techniques have expanded, the indications have extended to corpectomy for tumor resections.

DISCUSSION AND CONCLUSIONS

In the field of minimally invasive surgery, VATS now acts as a keyhole to the thoracic spine and an alternative to open thoracotomy for the treatment of several spinal conditions.Although VATS can be performed in such spine conditions, it is most beneficial in the treatment of scoliotic deformity, which requires taking a multilevel approach, from the upper to the lower thoracic spine.

Pioneering Experience of Uniportal Video-Assisted Thoracoscopic Surgery for Anterior Release of Severe Thoracic Scoliosis

The optimal way to treat severe thoracic scoliosis remains controversial. Compared with conventional procedures, the uniportal video-assisted thoracoscopic surgery (UniVATS) rises in popularity in thoracic surgery because of less pain and faster recovery. This retrospective study aimed to apply UniVATS to treat severe thoracic scoliosis. Between October 2013 and March 2018, eight scoliotic patients with extremely large Cobb angle and profoundly limited flexibility underwent UniVATS for anterior release, followed by posterior instrumentation and fusion. The mean age at the time of surgery was 14.8 ± 2.4 years and the mean follow-up was 2.2 ± 1.3 years. The average levels of anterior thoracic discectomy and posterior fusion were 3.6 ± 0.7 and 11.5 ± 1.2, respectively. The mean coronal and sagittal correction rates were 70 ± 19% and 71 ± 23%, respectively. UniVATS contributed to minor access trauma (3-cm incision) with minimal blood loss, shorter operation time (75 ± 13 mins), less requirement of stay in the intensive care unit (0.3 ± 0.5 day) or chest tube placement (0.3 ± 0.7 day), speedier and narcotic-free recovery, and earlier ambulation within one day. This is the first study to assess the safety and efficacy of UniVATS in the treatment of severely stiff thoracic scoliosis, providing comparable surgical outcomes, less pain, faster recovery and superior cosmetic results without significant complications.

Is vertebral rotation correction maintained after thoracoscopic anterior scoliosis surgery? A low-dose computed tomography study

Background

Axial vertebral rotation is a key characteristic of adolescent idiopathic scoliosis (AIS), and its reduction is one of the goals of corrective surgery. Recurrence of deformity after surgical correction may relate to rotation changes that occur in the anterior vertebral column after surgery, but whether any change occurs within the fused segment or in adjacent unfused levels following thoracoscopic anterior spinal fusion (TASF) is unknown. An analysis of measurements from an existing postoperative CT dataset was performed to investigate the occurrence of inter- and intra-vertebral rotation changes after TASF within and adjacent to the fused spinal segment and look for any relationships with the Cobb angle and rib hump in the two years after surgery.

Methods

39 Lenke Type 1 main thoracic patients underwent TASF for progressive AIS and low dose computed tomography scanning of the instrumented levels of the spine at 6 and 24 months after surgery. Vertebral rotation was measured at the superior and inferior endplates on true axial images for all vertebral levels in the fused segment plus one adjacent level cranially and caudally. Intra-observer variability for rotation measurements was assessed using 95% limits of agreement to detect significant changes in inter/intra-vertebral rotation.

Results

Significant local changes in inter- and intra-vertebral rotation were found to have occurred between 6 and 24 months after anterior surgical fusion within the fused spinal segment, albeit with no consistent pattern of location or direction within the instrumented fusion construct. No significant en-bloc movement of the entire fused spinal segment relative to the adjacent un-instrumented cranial and caudal intervertebral levels was found. No clear correlation was found between any vertebral rotation changes and Cobb angle or rib hump measures.

Conclusions

Localised inter- and intra-vertebral rotation occurs between 6 and 24 months after TASF, both within the instrumented spinal segments and in the adjacent un-instrumented levels of the adolescent spine. The lack of measurable en-bloc movement of the fused segment relative to the adjacent un-instrumented levels suggests that overall stability of the instrumented construct is achieved, however the vertebrae within the fusion mass continue to adapt and remodel, resulting in ongoing local anatomical and biomechanical changes in the adolescent spine.

Thoracoscopic Vertebrectomy for Thoracolumbar Junction Fractures and Tumors: Surgical Technique and Evaluation of the Learning Curve

STUDY DESIGN

Retrospective study.

OBJECTIVE

The authors evaluated the surgical technique and learning curve for video-assisted thoracoscopic surgery (VATS) for treating thoracolumbar junction burst fractures and bony tumors by examining surgical data and outcome for the first 30 VATS procedures performed by a single surgeon at a training institution.

SUMMARY OF BACKGROUND DATA

VATS is commonly used in the treatment of early-stage lung cancer. Widespread use of this technique among neurosurgeons is limited by the lack of cases and the steep learning curve.

METHODS

This study was a retrospective case series of the first 30 T12 and L1 thoracoscopic vertebrectomies from 2003 to 2008. The sample was limited to 1 surgeon and 1 region of the spine to minimize the potential variation so that a learning curve could be assessed. Surgical data and outcomes were analyzed. Estimated blood loss and operation time were analyzed using a linear generalized estimating equation model with a first-order autoregression correlation structure.

RESULTS

The average operative time for thoracoscopic corpectomy was 270±65 minutes (range, 160-416 min). Operating room time decreased significantly after the first 3 operations. The authors observed a stable linear decrease in operating time over the course of the study. The average blood loss during the thoracoscopic procedure was 433±330 mL (range, 100-1500 mL) and did not change as the series progressed. Complications and conversions to open procedures occurred in 2 patients and were evenly distributed throughout the series.

CONCLUSIONS

Thoracoscopic vertebrectomy at the thoracolumbar junction has a relatively long learning curve. In this series, operating room time improved dramatically after the first 3 cases but continued to improve subsequently. The learning curve can be accomplished without an increase in blood loss, complications, rate of conversion to open procedures, or frequency of misplaced instrumentation.

Surgical Treatment of Dystrophic Spinal Curves Caused by Neurofibromatosis Type 1: A Retrospective Study of 26 Patients

Dystrophic scoliosis in neurofibromatosis type 1 (NF-1) is difficult to treat. The purpose of this study was to review the clinical and radiological outcome of surgical treatment of dystrophic spinal curves in NF-1, for analyzing its efficacy, safety, and possible complications.This retrospective study consisted of 26 NF-1 patients with spinal deformities treated between 2003 and 2012 in our department. Preoperative X-ray, 3D-CT, and MRI were performed to evaluate the deformities of dystrophic scoliosis accurately. All patients were treated with posterior instrumented fusion alone using screws and hooks. According to the anatomical development situation of each patient's pedicles and the transverse processes, we chose different fixations and different fixed segments. The clinical and radiological outcomes of surgical correction were evaluated postoperatively.The average preoperative kyphosis was 43° (range 15-86°). The postoperative kyphosis had an average of 20° (range 10-39°) yielding 53% correction. At final follow-up, there was an average of 4.6% correction loss. The preoperative scoliosis Cobb angle had an average of 47° (range 35-96°). The postoperative scoliosis Cobb angle had an average of 21° (range 10-37°) yielding 55% correction. At final follow-up, there was an average of 6.6% correction loss. The apical vertebral body rotation was corrected by an average of 48%. At final follow-up, the score of the SRS-30 questionnaire ranged from 97 to 135 with an average of 109.In conclusion, the deformities of dystrophic scoliosis can be accurately determine through preoperative radiolographic evaluation, which plays an important role in guiding the correction of scoliosis program development. The results of this study demonstrate that satisfactory therapeutic effects can be achieved in the dystrophic scoliosis patients by preoperative meticulous surgical plans, intraoperative careful manipulation, and hybrid instrumentation.

Partial Intervertebral Fusion Secures Successful Outcomes After Thoracoscopic Anterior Scoliosis Correction: A Low-Dose Computed Tomography Study

STUDY DESIGN

Retrospective review of prospectively collected data.

OBJECTIVES

To analyze intervertebral (IV) fusion after thoracoscopic anterior spinal fusion (TASF) and explore the relationship between fusion scores and key clinical variables.

SUMMARY OF BACKGROUND INFORMATION

TASF provides comparable correction with some advantages over posterior approaches but reported mechanical complications, and their relationship to non-union and graft material is unclear. Similarly, the optimal combination of graft type and implant stiffness for effecting successful radiologic union remains undetermined.

METHODS

A subset of patients from a large single-center series who had TASF for progressive scoliosis underwent low-dose computed tomographic scans 2 years after surgery. The IV fusion mass in the disc space was assessed using the 4-point Sucato scale, where 1 indicates <50% and 4 indicates 100% bony fusion of the disc space. The effects of rod diameter, rod material, graft type, fusion level, and mechanical complications on fusion scores were assessed.

RESULTS

Forty-three patients with right thoracic major curves (mean age 14.9 years) participated in the study. Mean fusion scores for patient subgroups ranged from 1.0 (IV levels with rod fractures) to 2.2 (4.5-mm rod with allograft), with scores tending to decrease with increasing rod size and stiffness. Graft type (autograft vs. allograft) did not affect fusion scores. Fusion scores were highest in the middle levels of the rod construct (mean 2.52), dropping off by 20% to 30% toward the upper and lower extremities of the rod. IV levels where a rod fractured had lower overall mean fusion scores compared to levels without a fracture. Mean total Scoliosis Research Society (SRS) questionnaire scores were 98.9 from a possible total of 120, indicating a good level of patient satisfaction.

CONCLUSIONS

Results suggest that 100% radiologic fusion of the entire disc space is not necessary for successful clinical outcomes following thoracoscopic anterior selective thoracic fusion.

The effect of surgeon experience on outcomes of surgery for adolescent idiopathic scoliosis

BACKGROUND

Single-surgeon series investigating the learning curve involved in surgery for spinal deformity may be confounded by changes in technology and techniques. Our objective with this multicenter, prospective study was to present a cross-sectional analysis of the impact of surgeon experience on surgery for adolescent idiopathic scoliosis.

METHODS

All posterior-only surgical procedures for adolescent idiopathic scoliosis performed in the 2007 to 2008 academic year, with a minimum of two years of patient follow-up, were included. Two groups were created on the basis of surgeon experience: a young surgeons' group, which included patients of surgeons with less than five years of experience, and an experienced surgeons' group, which included patients of surgeons with five or more years of experience.

RESULTS

Nine surgeons (four young and five experienced) operated on a total of one hundred and sixty-five patients with adolescent idiopathic scoliosis. The surgeons' experience ranged from less than one year to thirty-six years in practice. The two groups had similar preoperative curve-magnitude measurements, SRS-22 (Scoliosis Research Society-22) scores, and distribution by Lenke curve type. There were significant operative and postoperative differences. The young surgeons fused an average of 1.2 levels more than the experienced surgeons (p = 0.045). The mean intraoperative estimated blood loss (EBL) of the young surgeons' group was more than twice that of the experienced surgeons' group (2042 mL compared with 1013 mL; p < 0.001). The duration of surgery was 458 minutes for the young surgeons compared with 265 minutes for the experienced surgeons (p < 0.001). The overall SRS-22 scores were significantly worse in the young surgeons' group (a mean of 4.1 compared with 4.5; p = 0.001). The difference between groups was also significant for the domains of pain (p = 0.016), self-image (p = 0.008), and function (p < 0.001). Complication rates did not differ significantly between the groups.

CONCLUSIONS

Operative results and health-related quality of life following surgery for adolescent idiopathic scoliosis were significantly and positively correlated with surgeon experience.

LEVEL OF EVIDENCE

Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

The impact of a distal expansion mechanism added to a standard pedicle screw on pullout resistance. A biomechanical study

BACKGROUND CONTEXT

Spinal deformity surgery in elderly patients is associated with an increased risk of implant loosening due to failure at the screw-bone interface. Several techniques can be used to increase the screw anchorage characteristics. Cement-augmented screw fixation was shown to be the most efficient method; however, this technique is associated with a risk of complications related to vertebral cement deposition and leakage. Hence, there is a need to further elaborate the alternative screw augmenting techniques to reduce the indications for bone cement.

PURPOSE

To analyze surgical alternatives to cement augmentation, the present study sought to quantify the impact of a distal expansion mechanism added to a standard pedicle screw on an axial pullout resistance.

STUDY DESIGN

A biomechanical laboratory study on the uniaxial pullout resistance of a standard pedicle screw versus a customized pedicle screw with a distal expansion mechanism.

METHODS

A total of 40 vertebrae from seven fresh-frozen human specimens were harvested and subjected to a computed tomography scanning and an analysis of the bone mineral density (BMD). The vertebrae were instrumented with a standard 6.0-mm pedicle screw and a modified 6.0-mm pedicle screw with a distal expansion mechanism added. The actual working length of both screws inside the vertebrae was identical. The distal expansion mechanism made up one-fifth of the shaft length. The accuracy of the screw insertion was assessed using biplanar radiographs and by inspection. Analysis of resistance to pullout was performed by a coaxial alignment of the pedicle screws and attachment to an electromechanical testing machine. The pullout rate was 5 mm/min, and the load-displacement curve was recorded until the force of the pullout resistance peaked. The peak load-to-failure was measured in Newtons and reported as the ultimate failure load. With each test, the mode of failure was noted and analyzed descriptively.

RESULTS

A total of 17 vertebrae with matched pairs of standard and expansion pedicle screws were eligible for the final statistical analysis. The BMD of the vertebrae tested was 0.67±0.19 g/cm³. The screw length was 50 mm, and the actual working length of both screws was 40.3±4.2 mm. The ultimate failure load of the standard screw was 773.8±529.4 N and that of the expansion screw was 910.3±488.3 N. Statistical analysis revealed a strong trend toward an increased failure load with the expansion screw (p=.06). The mean increase of the ultimate failure load was 136.5±350.4 N. Abrupt vertebral fracture at the vertebral body-pedicle junction and the pedicle occurred seven times with the expansion screw and only five times with the standard screw (p=.16).

CONCLUSIONS

Our study indicates that adding a distal expansion mechanism to a standard pedicle screw increases the failure load by one-fifth. Modern expansion screws might offer an intermediate solution for the augmentation of screw-rod constructs in osteoporotic bone while reducing the need for cement-augmented screws and avoiding the related risks.

Case report: Curetting osteoid osteoma of the spine using combined video-assisted thoracoscopic surgery and navigation

BACKGROUND

A spinal osteoid osteoma is a rare benign tumor. The usual treatment involves complete curettage including the nidus. In the thoracic spine, conventional open surgical treatment usually carries relatively high surgical risks because of the close anatomic relationship to the spinal cord, nerve roots, and thoracic vessels, and pulmonary complications and postoperative pain.

CASE REPORT

We report the case of a 16-year-old girl with a symptomatic osteoid osteoma at the T9 level whose lesion was currettaged using video-assisted thoracoscopic surgery (VATS) guided by a navigation system (VATS-NAV). There were no complications and the patient had immediate relief of the characteristic pain after surgery and was asymptomatic at 5 months' followup.

LITERATURE REVIEW

Progressive advances in the technology of spinal surgery have evolved to offer greater safety and less morbidity for patients. The advent of minimally invasive surgery has expanded the indications for VATS for anterior spinal disorders. Spinal navigation systems have become useful tools allowing localization and excision of the nidus of osteoid osteomas with minimal bone resection and without radiation exposure.

CLINICAL RELEVANCE

The VATS-NAV combination in our patient allowed accurate localization and guidance for complete excision of a spinal osteoid osteoma through a minimally invasive approach without compromising spinal stability.

ProDisc-L learning curve: 24-Month clinical and radiographic outcomes in 44 consecutive cases

Background

Total disc replacement (TDR) promises preservation of spine biomechanics in the treatment of degenerative disc disease but requires more careful device placement than tradition fusion and potentially has a more challenging learning curve.

Methods

A cohort of 44 consecutive patients had 1-level lumbar disc replacement surgery at a single institution by a single surgeon. Patients were followed up clinically and radiographically for 24 months. Patients were divided into 2 groups of 22 sequential cases each. Clinically, preoperative and postoperative Oswestry Disability Index, visual analog scale, Short Form 12 (SF-12) Mental and Physical Components, and postoperative satisfaction were measured. Radiographically, preoperative and postoperative range of motion (ROM) dimensions, prosthesis deviation from the midline, and disc height were measured. TDR-related complications were noted. Logarithmic curve–fit regression analysis was used to assess the learning curve.

Results

Operative time decreased as cases progressed, with an asymptote after 22 cases. The operative time for the later group was significantly lower (P < .0005), but hospital stay was significantly longer (P = .03). There was no significant difference in amount of blood loss (P = .10) or prosthesis midline deviation (P = .86). Clinically, there was no significant difference in postoperative scores between groups in Oswestry Disability Index (P = .63), visual analog scale (P = .45), SF-12 Mental Component (P = .66), SF-12 Physical Component (P = .75), or postoperative satisfaction (P = .92) at 24 months. Radiographically, there was no significant difference in improvement between groups in ROM (P = .67) or disc height (P = .87 for anterior and P = .13 for posterior) at 24 months. For both groups, there was significant improvement for all clinical outcomes and disc height over preoperative values. One patient in the later group had device failure with subluxation of the polyethylene, which required revision.

Conclusions/level of evidence

Early experience can quickly reduce operative time but does not affect clinical outcomes or ROM significantly (level IV case series).

Clinical relevance

Lumbar TDR is a rapidly learnable technique in treatment of degenerative disc disease.

The relationship between deformity correction and clinical outcomes after thoracoscopic scoliosis surgery: a prospective series of one hundred patients

STUDY DESIGN

Prospective clinical case series of 100 patients receiving thoracoscopic anterior scoliosis correction.

OBJECTIVE

To evaluate the relationship between clinical outcomes of thoracoscopic anterior scoliosis surgery and deformity correction, using the Scoliosis Research Society (SRS) outcomes instrument.

SUMMARY OF BACKGROUND DATA

Surgical treatment of scoliosis is quantitatively assessed in the clinic, using radiographic measures of deformity correction and the rib hump, but it is important to understand the extent to which these quantitative measures correlate with self-reported improvements in patients' quality of life after surgery.

METHODS

A series of 100 consecutive adolescent idiopathic scoliosis patients received a single anterior rod via a thoracoscopic approach at the Mater Children's Hospital, Brisbane, Australia. Patients completed SRS outcomes questionnaires before surgery and at 24 months after surgery. Multiple regression and t tests were used to investigate the relationship between SRS scores and deformity correction achieved (radiographic measurements and rib hump) after surgery.

RESULTS

There were 94 females and 6 males with a mean age of 16.1 years. The mean Cobb angle improved from 52° before surgery to 25° after surgery (52%) and the mean rib hump improved from 16° to 8° (51%). The mean total SRS score for the cohort was 99.4/120. None of the deformity-related parameters in the multiple-regression were significant. However, patients with the lowest postoperative major Cobb angles reported significantly higher SRS scores than those with the highest postoperative Cobb angles, but there was no difference on the basis of rib hump correction. There were no significant differences between patients with either rod fractures or screw-related complications compared to those without complications.

CONCLUSION

Patients undergoing thoracoscopic anterior scoliosis correction reported good SRS scores which are comparable with those in previous studies. Postoperative major Cobb angle is a significant predictor of patient satisfaction when comparing subgroups of patients with the highest and lowest postoperative Cobb angles.

Approach-related morbidity in transthoracic anterior spine surgery: a clinical study and review of literature

BACKGROUND: Anterior access to the thoracic spine is done by open thoracotomy (OTC) or video-assisted thoracoscopic surgery (VATS). VATS is known as the method which results in lower morbidity rates, but there is little evidence of its less invasiveness. Objective: The current study yielded for outcome data concerning patients' perception of approach-related morbidity (ArM) following OTC for spinal surgery and that of a control group having a chest tube thoracotomy (CTT). METHODS: We performed a questionnaire assessment of ArM after OTC and CTT. Applying strict inclusion criteria, we compared outcomes in terms of percentage morbidity (Morbidity %) of 43 patients that underwent OTC for instrumented scoliosis correction to 30 patients that had CTT for minor thoracic pathologies (e.g., pneumothorax). RESULTS: Mean age in CTT and OTC Group was 50.2 and 16.5 years old, follow-up was of 32.2 and 58.4 months, and mean incision length was 2.5 and 25.5 cm, respectively. Mean number of levels fused in the OTC Group was 5.8. Mean morbidity (0% delineating no cases, 100% delineating highest morbidity) for the CTT Group was 10.8±15.4% (0-59.5%), 42% of patients had no morbidity. Signs of intercostal neuralgia (ICN) were present in 16.7%. A total of 35.5% had a morbidity >10% (mean: 27.5%), and 10% of morbidity cases were defined as having a chronic post-thoracotomy pain (CPP). In the OTC Group, mean morbidity was 7.0±12.7% (0-52.1%), 44% had no morbidity. Out of the sample, 18.6% had morbidity >10% (mean: 28.6%). Signs of ICN were present in 14%. In both groups, the presence of ICN had a significant impact on and showed correlation with morbidity (p<0.0001). In terms of clinical judgement, the severity of the ArM after a CTT or OTC was generally mild except for one patient in each group. Age and follow-up were significantly different between groups (p<0.0001, p=0.02), but the intergroup difference in morbidity was not significant (p=0.08). CONCLUSIONS: ArM after open thoracic spinal surgery or VATS procedures can be assessed using the questionnaire. To put ArM of OTC into perspective, a Control Group with simple CTT was selected, demonstrating that morbidity was not different between the OTC and CTT groups. Patients with increased signs of ICN do worse which was reflected by increased morbidity in both groups. The study demonstrates that not only the cosmesis is not a concern for patients undergoing OTC, but neither is the ArM a concern, equalling that of a simple CTT.

Radiographic outcomes over time after endoscopic anterior scoliosis correction: a prospective series of 106 patients

STUDY DESIGN

A prospective, consecutive series of 106 patients receiving endoscopic anterior scoliosis correction.

OBJECTIVE

To analyze changes in radiographic parameters and rib hump in the 2 years after surgery.

SUMMARY OF BACKGROUND DATA

Endoscopic anterior scoliosis correction is a level sparing approach and therefore, it is important to assess the amount of decompensation which occurs after surgery.

METHODS

All patients received a single anterior rod and vertebral body screws using a standard compression technique. Cleared disc spaces were packed with either mulched femoral head allograft or rib head/iliac crest autograft. Radiographic parameters (major, instrumented, minor Cobb, T5-T12 kyphosis) and rib hump were measured at 2, 6, 12, and 24 months after surgery. Paired t tests and Wilcoxon signed ranks tests were used to assess the statistical significant of changes between adjacent time intervals.

RESULTS

Mean loss of major curve correction from 2 to 24 months after surgery was 4 degrees. Mean loss of rib hump correction was 1.4 degrees. Mean sagittal kyphosis increased from 27 degrees at 2 months to 30.6 degrees at 24 months. Rod fractures and screw-related complications resulted in several degrees less correction than patients without complications, but overall there was no clinically significant decompensation after complications.

CONCLUSION

There are small changes in deformity measures after endoscopic anterior scoliosis surgery, which are statistically significant but not clinically significant.

Novel dual-rod screw for thoracoscopic anterior instrumentation: biomechanical evaluation compared with single-rod and double-screw/double-rod anterior constructs

STUDY DESIGN

A novel dual-rod screw was designed to provide a second-rod augmentation at the critical apical/middle segments of the single-rod thoracoscopic anterior construct. Biomechanical testing was performed on pig thoracic spines instrumented with 7-segment anterior scoliosis constructs.

OBJECTIVES

To analyze the biomechanical performance of the new implant, and compare it to a single-rod and double-rod anterior constructs.

SUMMARY OF BACKGROUND DATA

Using single-rod thoracoscopic anterior instrumentation for thoracic scoliosis, the complications of rod breakage at apex, high rate of nonunion, and resultant loss of coronal and sagittal correction has been reported. Inadequate construct stiffness because of a smaller diameter single rod has been implicated as the cause of these complications.

METHODS

Twelve pig thoracic spines were instrumented over 7 segments with: (1) single-rod construct, (2) short second-rod augmentation at the apex of the single-rod construct, (3) long second-rod augmentation at middle segments of the single-rod construct, and (4) double-screw/double-rod anterior construct. The spines were tested in flexion-extension, left-right lateral bending, and torsion, using pure bending moments. Strain gauges attached to the primary single rod at the cephalad, middle, and caudal portions were used and the maximum tensile stress was recorded.

RESULTS

In the single-rod construct, the middle portion stress was 39% to 51% greater than the stress in the cephalad and caudal portions in flexion-extension (P < 0.05), and the cephalad portion stress was 39% to 65% greater than the stress in the middle and caudal portions in right lateral bending and torsion (P < 0.05). When a second rod was added at the apical/middle portion, the middle portion stress decreased from 50% to 72% in flexion-extension and right lateral bending (P < 0.05). In addition, the second rod decreased the primary single-rod stress at the cephalad portion by 48% (left torsion) and the caudal portion by 50% (flexion). Double-screw/double-rod construct significantly increases the construct stiffness in comparison with the single-rod construct. However, it did not add any construct stiffness at the critical apical segments when compared to the constructs in which the second rod augmented the single-rod constructs.

CONCLUSION

A novel dual-rod screw was designed to combine the standard single-rod construct with the addition of a second rod at the critical apical/middle segments and increase construct stiffness and stability. This implant may therefore prevent pseudarthrosis and rod breakage by enhancing construct stiffness.

DECISION MAKING IN PEDIATRIC SPINAL DEFORMITY

OBJECTIVE

To review the concepts involved in the decision-making process for management of pediatric patients with spinal deformity.

METHODS

The literature was reviewed in reference to pediatric deformity evaluation and management.

RESULTS

Pediatric spinal deformity includes a broad range of disorders with differing causes, natural histories, and treatments. Appropriate categorization of pediatric deformities is an important first step in the clinical decision-making process. An understanding of both nonoperative and operative treatment modalities and their indications is requisite to providing treatment for pediatric patients with spinal deformity. The primary nonoperative treatment modalities include bracing and casting, and the primary operative treatments include nonfusion instrumentation and fusion with or without instrumentation. In this article, we provide a review of pediatric spinal deformity classification and an overview of general treatment principles.

CONCLUSION

The decision-making process in pediatric deformity begins with appropriate diagnosis and classification of the deformity. Treatment decisions, both nonoperative and operative, are often predicated on the basis of the age of the patient and the natural history of the disorder.

[The dorsal spondylodesis of rotationally unstable thoracic fractures. Is additional ventral stabilization necessary?]

METHODS

A total of 60 patients with solely dorsally reconstructed type C fractures of the thoracic spine admitted between January 2000 and December 2003 were retrospectively evaluated. Stability was determined by measuring kyphosis of the vertebral body, the operated segments and of lateral bending on the basis of plain films and computed tomography immediately postoperatively and after 2 and 19 months.

RESULTS

There were 48% C2, 38% C1 and 13% C3 fractures. Of the injuries, 28% were caused by motorbike accidents, 25% by car accidents, 23% by falling from a height, 13% by suicidal jumps, 3% by ski accidents and 3% for other reasons. A total of 92% of the patients had severe thoracic trauma as attendant injuries, 42% further vertebral fractures, 35% a head injury, 30% an extremity fracture, 15% a clavicle fracture, 8% an abdominal trauma and 7% a fractured pelvis. At 19+/-12 months postoperatively, the angle of the operated segments increased by 4.7 degrees +/-4.0 degrees and that of lateral bending of the operated segments by 0.7 degrees +/-1.8 degrees compared to the immediate postoperative values.

CONCLUSION

In spite of the high instability of the injured spine, the collective examined had no relevant postoperative loss of correction and no increase in lateral bending. Therefore, a solely dorsal reconstruction is sufficient, reasonable and economical.

Clinical Analysis of Video-assisted Thoracoscopic Spinal Surgery in the Thoracic or Thoracolumbar Spinal Pathologies

OBJECTIVE

Thoracoscopic spinal surgery provides minimally invasive approaches for effective vertebral decompression and reconstruction of the thoracic and thoracolumbar spine, while surgery related morbidity can be significantly lowered. This study analyzes clinical results of thoracoscopic spinal surgery performed at our institute.

METHODS

Twenty consecutive patients underwent video-assisted thoracosopic surgery (VATS) to treat various thoracic and thoracolumbar pathologies from April 2000 to July 2006. The lesions consisted of spinal trauma (13 cases), thoracic disc herniation (4 cases), tuberculous spondylitis (1 case), post-operative thoracolumbar kyphosis (1 case) and thoracic tumor (1 case). The level of operation included upper thoracic lesions (3 cases), midthoracic lesions (6 cases) and thoracolumbar lesions (11 cases). We classified the procedure into three groups: stand-alone thoracoscopic discectomy (3 cases), thoracoscopic fusion (11 cases) and video assisted mini-thoracotomy (6 cases).

RESULTS

Analysis on the Frankel performance scale in spinal trauma patients (13 cases), showed a total of 7 patients who had neurological impairment preoperatively : Grade D (2 cases), Grade C (2 cases), Grade B (1 case), and Grade A (2 cases). Four patients were neurologically improved postoperatively, two patients were improved from C to E, one improved from grade D to E and one improved from grade B to grade D. The preoperative Cobb's and kyphotic angle were measured in spinal trauma patients and were 18.9+/-4.4 degrees and 18.8+/-4.6 degrees , respectively. Postoperatively, the angles showed statistically significant improvement, 15.1+/-3.7 degrees and 11.3+/-2.4 degrees , respectively (P<0.001).

CONCLUSION

Although VATS requires a steep learning curve, it is an effective and minimally invasive procedure which provides biomechanical stability in terms of anterior column decompression and reconstruction for anterior load bearing, and preservation of intercostal muscles and diaphragm.

Scoliosis associated with neurofibromatosis

Neurofibromatosis type 1 (NF-1) is a multisystemic disease. It may manifest as abnormalities of the nervous tissue, bones, soft tissue, and skin. The manifestations of NF-1 vary from person to person and range from subclinical to severe. Individuals who carry the gene eventually exhibit some clinical feature of the disease. The penetrance for NF-1 nears 100% during adulthood. Skeletal abnormalities are common in NF-1, with most patients presenting with some type of bony dysplasia. The orthopedic complications usually appear early. They include spinal deformities, such as scoliosis or kyphosis, congenital tibial dysplasia with bowing and pseudarthrosis of the tibia, forearm, other bones, as well as overgrowth phenomenon of an extremity, and soft tissue tumors.

Video-assisted thoracoscopic surgery compared with thoracotomy: early and late follow-up of radiographical and functional outcome

BACKGROUND CONTEXT

Video-assisted thoracoscopic surgery (VATS) is a new technique that allows for access to anterior spinal pathology using a minimally invasive approach. Proponents of this procedure argue that anterior thoracic spine surgery can be performed with the same accuracy and completeness as is possible by the conventional open approach but through much smaller skin and muscle incisions. Advantages of VATS include decreased blood loss, shorter hospital stay, and improved cosmesis.

PURPOSE

To detect if VATS is equally as effective as open thoracotomy, both combined with instrumented posterior spinal fusion, with respect to fusion rate, percent curve correction, and functional outcome.

STUDY DESIGN

Retrospective case control.

PATIENT SAMPLE

Seventeen patients underwent VATS/instrumented posterior spinal fusion for thoracic curvatures exceeding 50 degrees . A control cohort of patients that were age matched, sex matched, and curve magnitude matched underwent open thoracotomy/instrumented posterior spinal fusion.

OUTCOME MEASURES

Percentage of curve correction, fusion rate, intraoperative and postoperative clinical parameters, and functional outcome scores.

METHODS

Preoperative and postoperative radiographs were analyzed to calculate the percentage of major curve correction in the coronal and sagittal planes as well as the rate of fusion. In addition, operative reports and medical records were analyzed for the following outcomes: estimated operative blood loss, length of surgery, chest tube output, length of hospitalization, and complications. Average follow-up time was 26 months in the VATS group and 27 months in the thoracotomy group. Finally, functional outcome was assessed using the Scoliosis Research Society (SRS-22) and Oswestry Disability Index (ODI) scoring system.

RESULTS

The VATS group (mean age, 30) averaged 5.4 anterior levels and 11 posterior levels fused. The thoracotomy group (mean age, 32) averaged 5.8 anterior levels and 12 posterior levels fused. Estimated blood loss was nearly identical for the posterior procedures in both groups, whereas the anterior blood loss was significantly higher in the thoracotomy group as compared with the VATS group (541 cc vs. 288 cc). Operative time did not differ significantly between the two cohorts. Percent curve correction immediately postoperative (52% correction VATS; 51% correction thoracotomy) as well as at the 2-year follow-up (50% VATS and 54% thoracotomy) was nearly identical. There was no difference in postoperative ODI (p=.6) or SRS scores (p=.5) between groups. Complications were frequent but not significantly different between the two groups (p=.3).

CONCLUSION

VATS is equally effective as thoracotomy with respect to fusion rate, major curve correction, and functional outcome scores. Although a decrease in operative blood loss was seen in the VATS patients, this was not clinically significant.

Perioperative Aspects of Endoscopic Anterior Scoliosis Surgery: The Learning Curve for a Consecutive Series of 100 Patients

The reported benefits of endoscopic versus open scoliosis surgery include improved visualization, a muscle sparing approach, reduced pulmonary morbidity, reduced pain, and improved cosmesis. Some aspects of the surgical learning curve for this technically demanding method have been previously reported; however, improvements in other factors with increasing experience have not been quantified. This paper presents a series of 100 consecutive endoscopic anterior scoliosis corrections performed between April 2000 and February 2006. We report changes in the following perioperative factors with increasing experience; operative set-up time, operative time, x-ray irradiation time, number of instrumented levels, blood loss, intercostal catheter drainage, chest drain removal time, days in intensive care, days to mobilize, days in hospital, and early complications. Statistical comparisons were made between the first 20 (1 to 20), middle 20 (41 to 60), and last 20 (81 to 100) cases. Results showed statistically significant improvements and increased consistency in operative time, operative set-up time, x-ray irradiation time, blood loss, hospital stay, and mobilization time with experience. The complication rate was comparable to other recently published endoscopic studies. In the last 20 cases of the series, operative times had reduced to 35 minutes per level, x-ray irradiation times to 15 seconds per level, and blood loss to 38 mL per level. Most perioperative surgical factors therefore improve significantly with increasing experience in endoscopic anterior scoliosis correction.

[Video-assisted thoracic surgery to treat spinal deformities: climbing the learning curve]

OBJECTIVE

The aim of this study was to analyze the impact of the learning curve on the preliminary results of video-assisted thoracic surgery for spinal deformities in a general hospital setting.

PATIENTS AND METHODS

We retrospectively reviewed the medical records of 15 patients who underwent video-assisted thoracic surgery performed by a multidisciplinary team comprising orthopedic and thoracic surgeons. Endoscopic anterior release and fusion were followed by posterior instrumentation in a single procedure. Demographic, orthopedic, morbidity, and mortality statistics were compiled for the 15 patients and compared to results reported for similar series.

RESULTS

Endoscopic surgery was indicated for 15 patients: 11 women (73.3%) and 4 men (26.7%). The median age was 15 years (interquartile range [IQR], 14-19 years). Three patients (20%) required conversion to thoracotomy. There were 2 serious (13.3%) and 3 minor complications (20%). They all resolved satisfactorily and there was no perioperative mortality. The median Cobb angle was 71 degrees (IQR, 63.75 degrees -75.25 degrees ) before surgery and 41 degrees (IQR, 30 degrees -50 degrees ) after surgery. Median duration of surgery was 360 minutes (IQR, 300-360 minutes), duration of postoperative recovery unit stay was 1.5 days (IQR, 1-2.75 days), and total hospital stay was 11.5 days (IQR, 8.25-14 days).

CONCLUSIONS

Despite the complexity of video-assisted thoracic surgical procedures, we believe they will become the standard approach to treating spinal deformities in the near future. By working together in general hospital settings, orthopedic and thoracic surgeons can help to overcome the steep yet manageable learning curve.

Video-assisted thoracoscopic surgery in idiopathic scoliosis: evaluation of the learning curve

STUDY DESIGN

Retrospective review of patients with idiopathic scoliosis who underwent same-day or staged anterior and posterior spinal fusion and segmental spinal instrumentation.

OBJECTIVE

Evaluation of our learning curve with video-assisted thoracoscopic surgery (VATS) with respect to operative time, blood loss, and complications in patients with idiopathic scoliosis.

SUMMARY OF BACKGROUND DATA

VATS is a minimally invasive alternative to thoracotomy in the management of idiopathic scoliosis. An increased or steep learning curve has been described in the initial application of this technique.

METHODS

We began performing VATS in 1998. We compared our first 25 consecutive VATS patients (Group 2) and subsequent 28 consecutive VATS patients (Group 3) to our previous 16 consecutive patients (Group 1) with a thoracotomy (1991-1998) for idiopathic scoliosis. Training at a sponsored regional course was obtained before performing our first VATS procedure.

RESULTS

VATS allowed more disc to be excised in Group 2 (4.5 +/- 1, 5.7 +/- 1, and 4.4 +/- 1 discs in Group 1, Group 2, and Group 3, respectively) and significantly decreased the anterior operative time (215 +/- 33, 260 +/- 56, and 177 +/- 47 minutes) and time per individual disc excision (50 +/- 13, 47 +/- 12, and 41 +/- 12 minutes), while providing comparable correction of the thoracic deformity (67% +/- 12%, 66% +/- 10%, and 70% +/- 13% correction). There was no increase in estimated intraoperative anterior blood loss (228 +/- 213, 183 +/- 136, and 211 +/- 158 mL), estimated blood loss per disc excised (51 +/- 42, 34 +/- 29 and 48 +/- 37 mL), or complications in the VATS groups. Complications were primarily pulmonary and resolved with medical therapy. Postoperative chest tube drainage (855 +/- 397, 462 +/- 249, and 561 +/- 261 mL) and total perioperative anterior blood loss (1083 +/- 507, 647 +/- 309, and 773 +/- 308 mL) were significantly decreased in the VATS groups, but this was attributed to the use of Amicar.

CONCLUSIONS

VATS is an effective procedure for anterior spinal fusion in idiopathic scoliosis. The learning curve is short, provided appropriate training is obtained.

Is anterior release effective to increase flexibility in idiopathic thoracic scoliosis? Assessment by traction films

With the advent of thoracoscopy, anterior release procedures in adolescent idiopathic scoliosis (AIS) have come into more frequent use, however, the indication criteria for an anterior release in thoracic AIS are still controversial in the literature. To date, few studies have assessed the influence on spinal flexibility and no study has so far been able to show a beneficial effect on the correction rate as compared to a single posterior procedure. The objective of this study was to evaluate the influence of thoracic disc excision on coronal spinal flexibility. Six patients (5 females, 1 male) with AIS and a mean age of 15.6 years (range 13-20 years) underwent an open anterior thoracic release prior to posterior instrumentation. Cotrel dynamic traction along with radiographs of the whole spine including traction films were conducted pre- and postoperatively and were evaluated retrospectively. The mean preoperative thoracic curve was 89.7 degrees +/- 15.4 degrees (range 65 degrees-110 degrees). The flexibility rate in Cotrel traction was 22.8 +/- 8.1%. After performance of the anterior release the thoracic curve showed a mean increase of coronal correction by 5.5 degrees +/- 5.0 degrees as assessed by traction radiographs. The flexibility index changed by 6.2 +/- 5.6%. After posterior instrumentation the thoracic curve was corrected to a mean of 36.5 degrees +/- 10.1 degrees (correction rate 59.6%). Disc excision in idiopathic thoracic scoliosis only slightly increased spinal flexibility as assessed by traction films. In our view a posterior release with osteotomy of the concave ribs (concave thoracoplasty, CTP) is more effective in increasing spinal flexibility. According to our clinical experience, an anterior release prior to posterior instrumentation in AIS should only be considered in hyperkyphosis, coronal imbalance or massive curves.

Video-assisted thoracoscopic surgery: the Cincinnati experience

Video-assisted thoracoscopic surgery is an alternative to open thoracotomy. We analyzed our experience during a consecutive series of 100 patients who had this procedure and who were available for study at 3-year followup. Video-assisted thoracoscopic surgery was done on patients with the following diagnoses: idiopathic scoliosis (n = 49), neuromuscular spinal deformity (n = 15), Scheuermann kyphosis (n = 15), congenital and infantile scoliosis (n = 5), neurofibromatosis (n = 5), Marfan (n = 1), postradiation scoliosis (n = 1), and repair of pseudoarthrosis (n = 1). Four patients had excision of the first rib to treat thoracic outlet syndrome. One patient had excision of an intrathoracic neurofibroma and one a benign rib tumor. One had anterior arthrodesis after fracture-dislocation of the thoracic spine and another had anterior fusion for vertebral osteomyelitis. The average operative time for the thoracoscopic anterior release with discectomy and arthrodesis was 253 minutes. The average number of discs excised was 8. Final postoperative scoliosis and kyphosis corrections were 68% and 90%, respectively. Complications related to thoracoscopy occurred in eight patients. Video-assisted thoracoscopic surgery provides a safe and effective alternative to open thoracotomy in the treatment of thoracic pediatric spinal deformities.