Mini Screws for Improving Accuracy in Navigation-assisted Spine Surgery.

STUDY DESIGN: Presentation of a surgical technique with accompanying video (Supplemental Digital Content 1, http://links.lww.com/CLINSPINE/A67) of an illustrative case. OBJECTIVE: The objective of this study was to present a helpful and easy-to-implement technique for improving initial referencing accuracy, as well as rereferencing accuracy in cases of multilevel instrumentation or in cases of dislocation of the reference array. SUMMARY OF BACKGROUND DATA: Navigation-assisted spine surgery has become standard of care in most hospitals performing complex spine interventions. Although short-segment instrumentations are fairly straight-forward with current hardware and software solutions, obtaining ideal accuracies and troubleshooting reference array disruptions remain challenging. METHODS: A surgical technique is presented as a step-by-step guide using intraoperative videos and photographs as well as imaging data in an illustrative case of thoracic hemivertebra resection and dorsal instrumentation. TECHNIQUE/RESULTS: After skin incision is performed at the index level, posterior soft tissue preparation is performed. Before firmly attaching the reference array to a spinous process we then insert a minimum of four 5 mm mini screws at any bony structure within the exposure. Then an intraoperative navigation scan (3-dimensional computed tomography or x-ray) is obtained, and initial referencing is performed using the previously inserted mini screws as landmarks. This yields mean accuracies of 1 mm or lower and is easily verifiable by placing the navigation probe on a mini screw head. This action can be swiftly repeated at any time to prevent reduced accuracy because of insertion forces applied during pedicle screw placement. In addition, this allows for easy rereferencing in cases of disruption or complete removal of the navigation array, eliminating the need to perform additional computed tomography or x-ray scans during the procedure. CONCLUSIONS: The technique presented allows for rapid and highly accurate initial referencing and can be used in all cases of navigation-assisted spine surgery. It also allows for hassle-free rereferencing in cases of disruption or accidental removal of the reference array.

Does kyphotic deformity correlate with functional outcomes in fractures at the thoracolumbar junction treated by 360° instrumented fusion?

Sagittal balance and its relationship with back pain and functional outcomes has become an important factor in the management of thoracolumbar fractures. The kyphosis threshold at the thoracolumbar junction (TLJ) that produces a significant functional impairment remains unclear. Ninety-four patients who were treated surgically for TLJ fractures were evaluated after a follow-up period of 2-10 years. Functional evaluation based on the Oswestry and Hannover Scores (HS) was performed. Additionally, such patients underwent clinical and radiological evaluation. A significant inversely proportional correlation between the HS and the degrees of local kyphosis ("K-Angle") (p = 0.0172) was found. A significant directly proportional correlation between Oswestry Score and "K-Angle" (p = 0.0142) was found. Significantly poorer scores with both measurement tools (Hannover and Oswestry Scores) were found in patients with a kyphosis higher than 12°.

Epithelioid hemangioma of the spine: a case series of six patients and review of the literature.

BACKGROUND CONTEXT: Epithelioid hemangioma (EH) of bone is a benign vascular tumor that can be locally aggressive. It rarely arises in the spine, and the optimum management of EH of the vertebrae is not well delineated. PURPOSE: The report describes our experience treating six patients with EH of the spine in an effort to document the treatment of the rare spinal presentation. STUDY DESIGN: This study is designed as a retrospective cohort study. PATIENT SAMPLE: A continuous series of patients with the diagnosis of EH of the spine who presented at our institution. OUTCOME MEASURES: The clinical and radiographic follow-up of the patient population is documented. METHODS: The Bone Sarcoma Registry at our institution was used to obtain a list of all patients diagnosed with EH of the spine. Medical records, radiographs, and pathology reports were retrospectively reviewed in all cases. Only biopsy-proven cases were included. RESULTS: The six patients included five men and one woman who ranged in age from 20 to 58 years (with an average age of 40 years). The follow-up available for all six patients ranged from 6 to 115 (average 46.8) months. All patients presented with lytic vertebral body lesions. Five patients presented with pain secondary to their tumor, and the tumor in the sixth patient was found incidentally during the workup for a herniated disc. Three patients required surgical management for instability secondary to the destructive nature of their tumors, and two other patients required emergent decompression secondary to spinal cord compression by the tumor. The sixth patient was treated expectantly after biopsy confirmation. Three patients received postoperative radiation therapy as gross tumor remained after surgery. Three patients had gross total resections and did not receive postoperative radiation. Preoperative embolization was used in four patients. One patient continued to have back pain after surgery and radiation and another continued to have ataxia after surgery and radiation. No tumor locally recurred or progressed. CONCLUSIONS: Our data suggest that EH of the spine can be locally aggressive and lead to instability and cord compression. Surgery is required in such instances; however, observation should be considered in patients without instability or cord compression.

Rasterstereographic evaluation of interobserver and intraobserver reliability in postsurgical adolescent idiopathic scoliosis patients.

STUDY DESIGN: Evaluation of rasterstereographic examinations in postsurgical adolescent scoliosis patients: a reliability study. OBJECTIVE: To investigate the interobserver and intraobserver reliability of rasterstereographic 3-dimensional back surface analysis and reconstruction of spine parameters including trunk length, trunk inclination, lateral deviation, kyphotic and lordotic angles in adolescent idiopathic scoliosis patients after scoliosis surgery. SUMMARY OF BACKGROUND DATA: The rasterstereography device formetric III 4D has been in routine clinical use for patients with scoliosis and other spinal deformities, reducing the patients' radiation exposure considerably. The reliability of this device has previously been examined in healthy volunteers but not in patients after scoliosis surgery. MATERIALS AND METHODS: Thirty-nine adolescent idiopathic scoliosis patients (32 women and 7 men) after scoliosis surgery with a mean age of 23.5 years (±10.6 y) were examined rasterstereographically by 5 investigators. Each investigator made a series of 3 measurements of each participating patient consecutively. The intraclass correlation coefficient (ICC) and the Pearson product moment correlation were calculated. In addition, the comparative analysis of the first and 15th measurements was assessed. RESULTS: The ICCs of all investigated parameters demonstrated very high interobserver and intraobserver reliability. The maximum ICC (0.988) for interobserver reliability of the 5 investigators was found for the trunk length and the minimum ICC (0.918) for lateral deviation. There were highly significant positive correlations between the first, second, and third measurements (r=0.994-0.697; P<0.001) for intraobserver reliability. Overall highly significant correlation was found comparing the results of the first and the 15th rasterstereographic measurement. CONCLUSIONS: The reliability of rasterstereography formetric III 4D in regard to the investigated parameters is excellent. The device can be used very efficiently by 1 or multiple investigators to analyze postsurgical adolescent idiopathic scoliosis patients in clinical practice, requiring only a single investigational exposure.

Efficacy of hemivertebra resection for congenital scoliosis: a multicenter retrospective comparison of three surgical techniques.

STUDY DESIGN: Multicenter, retrospective study. OBJECTIVE: To compare the outcomes of three surgical treatments for congenital spinal deformity due to a hemivertebra. SUMMARY OF BACKGROUND DATA: Congenital anomalies of the spine can cause significant and progressive scoliosis and kyphosis. Their management may be challenging and controversy remains over the "best" surgical treatment. METHODS: A multicenter retrospective study of patients with congenital spinal deformity due to 1 or 2 level hemivertebra(e) was performed. The surgical treatments included hemiepiphysiodesis or in situ fusion (group 1), instrumented fusion without hemivertebra excision (group 2), or instrumented hemivertebra excision (group 3). RESULTS: Seventy-six patients with minimum 2-year follow-up were evaluated. The mean age was 8 years (range: 1-18). The hemivertebra were fully segmented, nonincarcerated (67%), incarcerated (1%), and semisegmented (32%). There were 65 patients with single hemivertebra and 11 patients with double hemivertebra. There were 14 (18.4%) group 1, 20 (26.3%) group 2, and 42 (55.3%) group 3 patients. Group 1 (37 ± 14°) and group 3 (35 ± 26°) patients had smaller preoperative curves than group 2 patients (55 ± 26°) (P < 0.01). Group 3 had better percent correction at 2 years than groups 1 and 2 (P < 0.001). Group 3 had shorter fusion (P = 0.001), less estimated blood loss (EBL, P = 0.03), and a trend toward shorter operative times than group 2 (P = 0.10). The overall complication rate for the entire group was 30% group 1 (23%), group 2 (17%), and group 3 (44%) (P = 0.09). CONCLUSION: While hemivertebra resection for congenital scoliosis had a higher complication rate than either hemiepiphysiodesis/in situ fusion or instrumentated fusion without resection, posterior hemivertebra resection in younger patients resulted in better percent correction than the other two techniques.

Ventral cancellous bone augmentation of the dens and temporary instrumentation C1/C2 as a function-preserving option in the treatment of dens pseudarthrosis.

STUDY DESIGN: An innovative function preserving technique for the treatment of odontoid nonunion via ventral cancellous bone augmentation of the dens is described. A retrospective clinical study of 17 patients, thus treated by this technique is reported. OBJECTIVES: Assessment of a new method, which preserves the rotational mobility of the C1/C2 joint. SUMMARY OF BACKGROUND DATA: Nonunion after odontoid fractures are usually treated by posterior fusion of C1/C2. Although there are reports of good clinical results, restriction of rotational mobility is inevitable. METHODS: Seventeen patients with dens pseudarthrosis or delayed healing were operated on between the year 1991 and 2005. A hole was drilled in the dens and packed with autologous bone graft. Temporary Instrumentation C1/C2 (anteriorly or posteriorly) was performed for 3 to 4 months. Patients were evaluated clinically and radiographically, rotation computed tomography or magnetic resonance imaging studies were conducted. RESULTS: Fifteen patients were available for follow-up. Nine patients demonstrated healing of the pseudarthrosis with preservation of C1/C2 joint mobility (confirmed by rotation-computed tomgraphy or rotation -magnetic resonance imaging in 7 cases, average segmental rotation 37.3 degrees). Four patients showed persistent pseudarthrosis (2 were fused by posterior C1/C2 fixation) and 2 patients demonstrated spontaneous C1-C2 fusion. CONCLUSIONS: Ventral cancellous bone augmentation of the dens and temporary instrumentation C1/C2 is a function-preserving option in the treatment of dens pseudarthrosis.

Adolescent idiopathic scoliosis treated with open instrumented anterior spinal fusion: five-year follow-up.

STUDY DESIGN: A multicenter prospective database was queried for patients who underwent open instrumented anterior spinal fusion (OASF) for treatment of primary thoracic (Lenke 1) adolescent idiopathic scoliosis (AIS). OBJECTIVES: To present the intermediate radiographic and pulmonary function testing (PFT) data from patients who underwent OASF using modern, rigid instrumentation. SUMMARY OF BACKGROUND DATA: Anterior spinal fusion is an excellent method to correct the 3-dimensional deformity produced by AIS. Modern instrumentation consisting of stronger metals, unthreaded rods, and dual rod systems should theoretically decrease the incidence of rod breakage, pseudarthrosis, and loss of correction seen in earlier OASF studies. The paucity of intermediate and long-term data prevents surgeons and patients from making an informed decision regarding the true incidence of these complications. METHODS: Of 101 potential patients who underwent OASF with a minimum 5-year follow-up, 85 (85%) were studied. Standing radiographs were analyzed before surgery and at first standing erect, 2-year, and 5-year follow-up. PFT data were collected before surgery and at 5 years after surgery. RESULTS: Complete 5-year follow-up was obtained in 85 patients. Five years after surgery, the mean coronal correction was 26 degrees (51%; P < 0.05) and the thoracolumbar/lumbar curve improved 16 degrees (51%). There was a 9-degree (P < 0.001) increase in kyphosis, and there were 9 patients (11%) in whom the C7 plumb line translated >2 cm. There was a 6.7% decrease in predicted FEV1 over the 5-year period, from 75.5% +/- 13% before surgery to 68.8% +/- 2% at 5-year follow-up (P = 0.007); however, there was no significant change in FVC. There were 3 significant adverse events: 1 implant breakage requiring reoperation and 2 cases of progression of the main thoracic curve requiring reoperation. CONCLUSION: OASF is a reproducible and safe method to treat thoracic AIS. It provides good coronal and sagittal correction of the main thoracic and compensatory thoracolumbar/lumbar curves that is maintained with intermediate term follow-up. In skeletally immature children, this technique can cause an increase in kyphosis beyond normal values, and less correction of kyphosis should be considered during instrumentation. As with any procedure that employs a thoracotomy, pulmonary function is mildly decreased at final follow-up.

Outcome of 132 operations in 97 patients with chordomas of the craniocervical junction and upper cervical spine.

OBJECTIVE: To study the outcomes of surgery for chordomas of the craniocervical junction and upper cervical spine as well as complication rates, survival, and associated adverse factors. METHODS: Retrospective review of patients (1982-2007) at 2 European centers who underwent transoral, transfacial, transmandibular, and anterior cervical approaches for excision of chordomas of the craniocervical junction and cervical spine. The chi test and Fisher exact test were used to determine significant adverse factors (P < .05), and log-rank survival analysis was used to compare outcome in different groups. RESULTS: One hundred thirty-two operations were performed in 97 patients. The most common operations were transoral surgeries and maxillotomies. After surgery, neck pain was the same or better in 98.1% of patients. Of the 18.6% of patients who presented with myelopathy, 27.8% improved, 44.4% remained unchanged, and 27.8% deteriorated. Major complication rates were velopharyngeal incompetence, 3.1%; vertebral artery stroke, 1%; wound infection, 3.1%; dysphagia, 3.1%; failure of fixation, 2.1%; sepsis, 3.1%; meningitis, 3.1%; and cerebrospinal fluid leakage, 6.2%. Five- and 10-year overall survivals were 55% and 36%, respectively. Patients who presented to our units for revision surgery, after prior attempts at resection elsewhere, were associated with a worse survival than patients who underwent de novo surgery. CONCLUSION: We present, to our knowledge, the largest published series of chordomas at the craniocervical junction. Complication rates for these major operations can be minimized at specialist centers, with careful patient selection and counseling. As complete or as radical an operation as possible should be performed at first presentation; the best chance for the patient is the first chance.

Hemivertebra resection and osteotomies in congenital spine deformity.

STUDY DESIGN: Retrospective study of posterior hemivertebra resection and osteotomies with transpedicular instrumentation in very young children. OBJECTIVE: Assessment of early intervention in congenital scoliosis with almost complete correction of the main deformity. SUMMARY OF BACKGROUND DATA: There is a trend to early correction of congenital deformities, however, there is a lack of long-term follow-up. METHODS: Forty-one children aged 1 to 6 years with congenital scoliosis were operated on by hemivertebra resection by a posterior only approach with transpedicular instrumentation. Mean age at time of surgery was 3 years 5 months. They were retrospectively studied with a mean follow-up of 6 years 2 months. RESULTS: In group 1 (patients without bar formation), the average Cobb angle of the main curve was 36 degrees before surgery and 7 degrees after surgery. Compensatory cranial curve improved spontaneously from 15 degrees to 3 degrees, compensatory caudal curve from 17 degrees to 4 degrees. The angle of kyphosis was 22 degrees before surgery and 8 degrees after surgery. In group 2 (patients with bar formation) the main curve improved from 69 degrees to 23 degrees, cranial curve from 27 degrees to 11 degrees, caudal curve from 34 degrees to 14 degrees, and kyphosis from 24 degrees to 9 degrees. CONCLUSION: Posterior hemivertebra resection, in case of bar formation with osteotomy of the bar, allows for excellent correction in both the frontal and sagittal planes, with a short segment of fusion. Early surgery in young children prevents the development of severe local deformities and secondary structural curves, thus allowing for normal growth in the unaffected parts of the spine.

Biomechanics and materials of reconstruction after tumor resection in the spinal column.

We initially review the general biomechanical principles that should be considered in surgical reconstruction of spinal tumors. This will be further clarified by more detailed descriptions for individual spinal regions in the subsequent part of the article. In the case of patients with spinal metastases, especially in patients with a median survival time less than a few months, a thorough review of the risks and benefits regarding surgical intervention must be discussed with the patient. However, once the decision for surgery has been made, a biomechanically sound reconstruction should be performed to help restore or maintain the patient's mobility.

Does spinal surgery improve the quality of life for those with extradural (spinal) osseous metastases? An international multicenter prospective observational study of 223 patients. Invited submission from the Joint Section Meeting on Disorders of the Spine and Peripheral Nerves, March 2007.

OBJECT: Opinions vary widely as to the role of surgery (from none to wide margin excision) in the management of spinal metastases. In this study the authors set out to ascertain if surgery improves the quality of remaining life in patients with spinal metastatic and tumor-related systemic disease. METHODS: The authors included 223 patients in this study who were referred by oncologists and physicians over a 2-year period. All underwent surgery. Surgery was classified according to extent of excision ranging from en bloc excision or debulking to palliative surgery. All patients had a histologically confirmed diagnosis of epithelial spinal metastasis, and an oncology specialist undertook appropriately indicated adjuvant therapy in almost half of the patients. RESULTS: The mean patient age was 61 years. Excisional en bloc or debulking surgery was performed in 74%; the rest had (minimal) palliative decompression. All patients considered for surgery were included in the study. Patients presented with pain in 92% of cases, paraparesis in 24%, and abnormal urinary sphincter function in 22% (5% were incontinent). Breast, renal, lung, and prostate accounted for 65% of the cancers, and in 60% of patients there were widespread spinal metastases (Tomita Type 6 or 7). The incidence of perioperative death (within 30 days of surgery) was 5.8%. Postoperatively 71% of the entire group had improved pain control, 53% regained or maintained their independent mobility, and 39% regained urinary sphincter function. The median survival for the cohort was 352 days (11.7 months); those who underwent excision survived significantly longer than those in the palliative group (p = 0.003). As with survival results, functional improvement outcome was better in those who underwent excision. CONCLUSIONS: Surgical treatment was effective in improving quality of life by providing better pain control, enabling patients to regain or maintain mobility, and offering improved sphincter control. Although not a treatment of the systemic cancer, surgery is feasible, has acceptably low mortality and morbidity rates, and for many will improve the quality of their remaining life.

Axial plane lumbar responses after anterior selective thoracic fusion for main thoracic adolescent idiopathic scoliosis.

STUDY DESIGN: A retrospective radiographic study. PURPOSE: To evaluate the axial plane lumbar responses after anterior selective thoracic fusion (STF) in patients with main thoracic adolescent idiopathic scoliosis (MT-AIS). OVERVIEW OF LITERATURE: Anterior scoliosis surgery induces more MT derotation through disc preparation than posterior surgery. METHODS: Twenty-eight MT-AIS patients treated with STF were evaluated after a minimum follow-up (FU) of 2 years. The MT and lumbar coronal angles, as well as the MT and lumbar rotational angles at the most rotated vertebrae were measured. RESULTS: At the last FU, the MT coronal correction and derotation rates were 65% and 41%, respectively. The lumbar coronal correction rate was 61% but there was minimal lumbar derotation (2%). Nine cases were decompensated (coronal balance >10 mm). After surgery, the compensated and decompensated groups showed similar MT coronal and axial correction rates. During the FU, the MT and lumbar apecies rotated in the same direction (r=0.443). In addition, significant MT derotation occurred in the decompensated group with increasing lumbar rotational correction loss. At the last FU, while the MT coronal correction was similar between the two groups, there was more MT derotation in the decompensated group. Furthermore, the MT rotational change was strongly associated with the coronal C7 plumb line position (r=0.728). CONCLUSIONS: After anterior STF in patients with MT-AIS, the final MT derotation is strongly associated with the coronal C7 plumb line position. During the FU, the excessive MT derotation in the decompensated group was attributed to excessive lumbar rotational correction loss.

Operative management of Scheuermann's kyphosis in 78 patients: radiographic outcomes, complications, and technique.

STUDY DESIGN: A retrospective multicenter review of 78 patients with Scheuermann's kyphosis treated operatively was conducted. OBJECTIVE: The purpose of this study was to evaluate correction of sagittal alignment, maintenance of correction, and occurrence of, and etiologic factors associated with, junctional kyphosis in patients managed operatively for Scheuermann's kyphosis. SUMMARY OF BACKGROUND DATA: There is a paucity of literature regarding the surgical treatment of Scheuermann's kyphosis using current implant systems and operative techniques. Junctional kyphosis has been shown to occur in up to one third of patients. Factors causing junctional kyphosis have not been clearly elucidated. Loss of correction has been variable based on the technique used. No clear-cut advantages or disadvantages have been shown for the use of anterior release. METHODS: Kyphosis, lordosis, C7 sagittal plumbline, apical translation, junctional sagittal alignment, and pelvic incidence were assessed among other radiographic parameters from a centralized database. The incidence of junctional kyphosis and its association to the above parameters and to fusion levels were assessed. Complication rates and differences between patients undergoing combined anteroposterior surgery and those having posterior surgery alone were evaluated. RESULTS: Of the 78 patients, 42 underwent combined anteroposterior procedures (Group 1) and 36 had posterior surgery only (Group 2). Mean age was 16.7 years. Overall, the greatest Cobb kyphosis of 78.8 degrees was corrected to 51.4 degrees at follow-up. Preoperative kyphosis was 82.6 degrees and 74.4 degrees for Groups 1 and 2, respectively (P < 0.001) and 55.8 degrees and 46.2 degrees at follow-up (P = 0.000). Loss of correction was 3.2 degrees (not significant) and 6.4 degrees (P = 0.000), respectively. Lordosis corrected from -65.5 degrees to -51.7 degrees . Proximal and distal junctional kyphosis of >or=10 degrees occurred in 25 (32.1%) and 4 (5.1%), respectively. The development of a proximal junctional kyphosis correlated directly with kyphosis at follow-up and indirectly with percent correction. Among patients with proximal junctional kyphosis, the magnitude of junctional kyphosis correlated directly with the degree of pelvic incidence. Pelvic incidence correlated directly with lumbar lordosis but not kyphosis. Twelve complications occurred in 12 patients, including posterior wound infection (1), distal (2), and proximal (1) junctional kyphosis, and pseudarthrosis (1), those requiring reoperation. CONCLUSION: This is one of the largest reported series of Scheuermann's kyphosis treated operatively to our knowledge. A high rate of junctional kyphosis, especially at the proximal end, is associated with surgery for Scheuermann's kyphosis using current techniques. Proximal junctional kyphosis is associated with higher magnitude of kyphosis at follow-up, less percent correction; its magnitude correlated directly with pelvic incidence. Loss of correction is less in patients undergoing combined anteroposterior surgery. Pelvic incidence correlates directly with lordosis but not kyphosis, suggesting that these parameters are not causative of Scheuermann's kyphosis.

C2 prosthesis: anterior upper cervical fixation device to reconstruct the second cervical vertebra.

Destruction of the second cervical vertebra leads to a highly unstable situation. Reconstruction is difficult because the axis plays a central role in rotatory movements and has a unique function in redistributing axial loads. The axis transfers the axial load of the two lateral masses of the atlas to three surfaces on the third cervical vertebra: the two articular facets and the vertebral body. As reconstruction is difficult and the instability in this region is life threatening, pathological processes are often treated less radically compared to other areas of the cervical spine. However, this more moderate approach may result in worse outcomes and prognoses. This paper presents the development of a new implant (C2 prosthesis) and two illustrative cases describing the implementation of this new implant. The C2 prosthesis provides anterior support and therefore allows a more radical surgical approach.

Treatment of vertebral osteomyelitis by radical debridement and stabilization using titanium mesh cages.

STUDY DESIGN: A retrospective clinical and radiologic evaluation of patients with vertebral osteomyelitis treated via radical debridement and stabilization using titanium mesh cages. OBJECTIVE: To assess the efficacy of titanium mesh cages in the treatment of active vertebral osteomyelitis. SUMMARY OF BACKGROUND DATA: Although titanium mesh cages have proven to be superior in trauma and tumor reconstructions, there are few reports regarding the use of titanium mesh cages in the presence of active pyogenic or tuberculotic vertebral osteomyelitis. METHODS: A total of 88 cases with vertebral osteomyelitis were operated on between January 2000 and December 2002. There were 2 craniocervical, 13 cervical, 19 thoracic, 11 thoracolumbar, and 43 lumbar infections. The titanium mesh cages replaced 1 disc in 34 cases, 1 vertebral body in 28 cases, 2 vertebral bodies in 23 cases, and 3 vertebral bodies in 3 cases. RESULTS: All patients showed a solid bony fusion without any recurrence of infection at latest follow-up. Changes in pain score, Frankel's classification, and blood parameters demonstrated a significant clinical improvement in all patients. The sagittal profile was restored. CONCLUSIONS: The use of titanium mesh cages in the treatment of vertebral osteomyelitis effectively reconstructs the anterior column, while adding stability and restoring the sagittal profile. There is no increase in the rate of recurrence or persistence of infection related to the implantation of titanium mesh cages.

Sagittal plane lumbar responses after anterior selective thoracic fusion for main thoracic adolescent idiopathic scoliosis.

STUDY DESIGN: A retrospective radiographic study. PURPOSE: To verify the correlation of sagittal and coronal plane changes after selective thoracic fusion in main thoracic (MT) adolescent idiopathic scoliosis (AIS). OVERVIEW OF LITERATURE: Sagittal plane deformity is known to be essential in the evolution of scoliosis. METHODS: Twenty-eight MT AIS patients treated by anterior selective thoracic fusion were evaluated after minimal follow-up of two years. The unfused lumbar area was divided into proximal and distal parts by the lumbar apex in the coronal plane, and into proximal and distal lumbar lordosis by L2 in the sagittal plane. Surgical motion (the difference between preoperative and postoperative values) and follow-up motion (the difference between postoperative and the last follow-up values) were compared. RESULTS: Immediately after surgery, as thoracic kyphosis increased, lumbar lordosis decreased (r=0.734); proximal lumbar lordosis increased, and distal lumbar lordosis decreased. The proximal lumbar area was mobilized in the sagittal plane, and was straightened in the coronal plane. However, the distal lumbar area was stabilized in the sagittal plane, and showed resistant motion against MT translation in the coronal plane. The surgical motion was correlated to the follow-up motion, i. e., was regulated during follow-up, and the regulatory motion was more precise in the distal than proximal lumbar area in both sagittal and coronal planes. CONCLUSIONS: Sagittal and coronal motions were co-related; optimal sagittal motions were necessary for optimal coronal motions after anterior selective thoracic fusion for MT AIS. Proximal and distal lumbar motions were different for different roles; the proximal lumbar area played a role as a bumper to absorb the MT translatory force, and the distal lumbar area played a role of resistance against MT translation.

Anatomic reduction and monosegmental fusion in high-grade developmental spondylolisthesis.

STUDY DESIGN: A retrospective review of the clinical and radiographic outcomes of reduction by temporary instrumentation of L4 and monosegmental fusion of L5/S1 in patients with high-grade developmental spondylolisthesis. OBJECTIVE: To assess the efficacy of this technique in the reduction of local deformity and correction of overall sagittal profile. SUMMARY OF BACKGROUND DATA: In situ fusions as well as partial reduction with fusion L4-S1 via various approaches have been described previously. To date and to our knowledge, there have been no reports describing complete reduction and monosegmental fusion for high-grade developmental spondylolisthesis. METHODS: A total of 27 consecutive patients with severe developmental spondylolisthesis of L5/S1 were treated with operative reduction via temporary instrumentation of L4 and monosegmental fusion of L5/S1. The clinical and radiographic outcomes were retrospectively reviewed for each case at a minimum of 2 years (mean follow-up of 45 months; range 24-80). Mean age at surgery was 16.7 years (range 9-29). RESULTS: At most recent follow-up, 23 patients were pain free. There were 4 patients who had moderate pain. All radiographic parameters improved. Mean slippage improved from 74.0% before surgery to 11.0% after surgery and 10.0% at latest follow-up. Slip angle improved from 36.6 degrees before surgery to 8.1 degrees after surgery and 7.6 degrees at latest follow-up. Sacral inclination improved from 34.6 degrees before surgery to 43.4 degrees after surgery and 47.2 degrees at latest follow-up. The overall sagittal profile improved dramatically. There was 1 superficial infection, 6 patients had L5 root symptoms (5 of these resolved, 1 patient had a persistent sensory deficit). Four patients had decompensation at L4/5 (2 reoperations). CONCLUSIONS: Reduction of L5/S1 with temporary instrumentation of L4 and monosegmental fusion of L5/S1 is an effective technique for the treatment of high-grade developmental spondylolisthesis. A complete reduction of local deformity and excellent correction of overall sagittal profile can be achieved. Fusion of the primarily healthy segment L4/5 can be avoided.

Hemivertebra resection in the cervical spine.

STUDY DESIGN: Retrospective study with clinical and radiologic evaluation of hemivertebra resection in children with congenital cervical scoliosis. OBJECTIVE: Assessment of hemivertebra resection in the treatment of congenital cervical scoliosis. SUMMARY OF BACKGROUND DATA: To our knowledge, this is the first report on hemivertebra resection in the midcervical spine. METHODS: Three patients with torticollis due to a cervical hemivertebra were operated on by hemivertebra resection and fusion of the adjacent vertebrae. Resection was performed by a posterior-anterior (-posterior) approach. Mean age at time of surgery was 9 years 3 months. They were retrospectively studied with a mean follow-up of 4.8 years. RESULTS: Mean segmental Cobb angle at the hemivertebra was 29 degrees before surgery, 5 degrees after surgery, and 6 degrees at latest follow-up. Head tilt improved from 17 degrees before surgery to 1 degrees after surgery, and 3 degrees at latest follow-up. Bony fusion was achieved in all cases. There was weakness of the left deltoid muscle in 1 case due to C5 root compression by a facet screw, which resolved completely after revision with change of the screw. CONCLUSIONS: Resection of a cervical hemivertebra may be an option in the treatment of congenital cervical scoliosis. A good correction of the local deformity and a complete correction of head tilt are achieved. By early operation in young children, the development of severe secondary deformities in the upper thoracic spine can be avoided.

Therapeutic options and results following fixed atlantoaxial rotatory dislocations.

Atlantoaxial rotatory dislocation (AARD) represents a rare pathological condition of the upper cervical spine that is frequently misdiagnosed, leading to a delay in therapy. In a long-term assessment of clinical and radiological results, three different therapeutic options with regard to the length of the dislocation-therapy interval (DTI) were evaluated. Twenty-six patients were treated for AARD from December 1988 until April 2000. Proper diagnosis was established after an average interval of 15 months. Three different therapeutical protocols were followed in order to reduce the dislocation: (1) closed transoral reposition under general anesthesia; (2) temporary transoral fixation utilizing the Harms T-plate; (3) definitive transoral fusion. The eight patients treated by closed reduction had the best pain relief. The average visual analogue scale (VAS) score was 96.6 points, while the rotatory motion of the upper cervical spine, as assessed by dynamic MRI, was 25.3 degrees to each side. The length of the dislocation-therapy-interval (DTI) averaged 1.4 months. A mean VAS Score of 92.3 points was recorded in the ten patients treated with a temporary fixation of C1/C2. In this subgroup the DTI had an average length of 5.3 months. The mean rotation to each side was 13.9 degrees . In the eight patients who underwent definitive fusion the mean VAS score was 60.6 points, while the average length of the DTI was 40.5 months. In conclusion, the clinical outcome and the subjective well-being following AARD deteriorates with increasing length of the dislocation-therapy interval.