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Background: The V2 segment of the vertebral artery (VA) typically runs through the transverse foramen of C2-C6. V2 injury may occur during anterior approaches to the cervical spine and can cause significant morbidity. We describe landmarks and microsurgical V2 repair techniques through the standard anterolateral cervical diskectomy approach., Methods: Five silicone-injected cadaveric heads (necks-C7) were dissected bilaterally. An anterolateral approach with C3-4, C4-5, and C5-6 diskectomies and an ipsilateral VA injury were simulated. VA approach and repair were performed using microdissection techniques. Landmarks to the VA were identified, and distances from landmarks to the VA were measured in horizontal and vertical planes. Operative photographs of stepwise approach and repair techniques were processed for stereoscopic illustration. An illustrative case describes microsurgery to successfully repair an inadvertent VA injury during a C3-C6 diskectomy and fusion procedure., Results: The anatomic landmarks delineated were the intervertebral disk, uncinate apices, and anterior tubercles of C4-C6 transverse processes. After temporary hemostasis with packing, VA exposure and repair included dissection of the longus colli muscle, removal of the anterior root of the transverse processes above and below the injury level, intertransversarii muscle removal, vertebral plexus opening, VA handling, and microsuturing. In 30 dissected cadaver intertransverse intervals, 13 medial, 7 lateral, and 3 anterior branches of the V2 were encountered at C3-C6 levels., Conclusion: Familiarity with relevant vascular surgical anatomy allows neurosurgeons to be prepared in cases of VA injury and may facilitate repair when the VA is injured during anterior cervical spine surgery., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Study Design: Retrospective chart review., Objective: To determine the long-term efficacy of 2-stage total en bloc spondylectomy (TES)., Summary of Background Data: TES is a well-described technique to achieve tumor-free margins, but it is a highly destabilizing procedure that necessitates spinal reconstruction. A 2-stage anterior/posterior approach for tumor resection and instrumentation has been shown to be biomechanically superior to the single-stage approach in achieving rigid fixation, but few clinical studies with long-term outcomes exist., Methods: A retrospective review was performed on patients undergoing a 2-stage TES for a spinal tumor between 1999 and 2011. Results were compared with those from a literature review of case series, with a minimum of 2-year follow-up, reporting on a single-stage posterior-only approach for TES., Results: Seven patients were identified (average follow-up 52.7 mo). Tumor location ranged from T1 to L3 with the following pathologies: metastasis (n=3), hemangioma (n=1), leiomyosarcoma (n=1), giant cell tumor (n=1), and chordoma (n=1). There were no significant surgical complications. All 7 patients had intact spinal fixation. There were no failures of the orthogonal fixation (pedicle screws or anterior fixation). The average modified Rankin Scale scores improved from 2.7 preoperatively to 0.7 at last follow-up. None of the patients in our series suffered local disease recurrence at last follow-up or suffered neurological deterioration. These results were comparable with those noted in the literature review of posterior-only approach, where 12% of patients experienced instrument failure., Conclusions: TES is a highly destabilizing procedure requiring reconstruction resistant to large multiplanar translational and torsional loads. A 2-stage approach utilizing orthogonal vertebral body screws perpendicular to pedicle screws is a safe and effective surgical treatment strategy. Orthogonal spinal fixation may lower the incidence of instrumentation failure associated with complete spondylectomy and appears to be comparable with a single-stage procedure. However, larger prospective series are necessary to assess the efficacy of this approach versus traditional means.

Study Design: The authors retrospectively reviewed a consecutive series of 231 patients with anterior lumbar interbody fusion (ALIF)., Objective: To determine the correlations among common medical conditions, demographics, and the natural history of lumbar surgery with outcomes of ALIF., Summary of Background Data: Multiple spinal disorders are treated with ALIF with excellent success rates. Nonetheless, adverse outcomes and complications related to patients' overall demographics, comorbidities, or cigarette smoking have been reported., Methods: The age, sex, body mass index (BMI), comorbidities, history of smoking or previous lumbar surgery, operative parameters, and complications of 231 patients who underwent ALIF were analyzed. Regression analyses of all variables with complications and surgical outcomes based on total Prolo scores were performed. Two models predicting Prolo outcome score were generated. The first model used BMI and sex interaction, whereas the second model used sex, level of surgery, presence of diabetes mellitus, and BMI as variables., Results: At follow-up, the rate of successful fusion was 99%. The overall complication rate was 13.8%, 1.8% of which occurred intraoperatively and 12% during follow-up. The incidence of complications failed to correlate with demographics, comorbidities, smoking, or previous lumbar surgery (P>0.5). ALIF at T12-L4 was the only factor significantly associated with poor patient outcomes (P=0.024). Both models successfully predicted outcome (P=0.05), although the second model did so only for males., Conclusions: Surgical level of ALIF correlated with poor patient outcomes as measured by Prolo functional scale. BMI emerged as a significant predictor of Prolo total score. Both multivariate models also successfully predicted outcomes. Surgical or follow-up complications were not associated with patients' preoperative status.

Study Design: Retrospective review., Objective: To compare surgical outcomes of patients who have undergone anterior lumbar interbody fusion (ALIF) with and without plating., Summary of Background Data: In biomechanical testing, ALIF constructs supplemented with plating (ALIFP) reduce range of motion and increase construct stiffness compared with ALIF alone. However, whether ALIFP constructs translate into improved clinical outcomes over ALIF alone is unknown., Methods: From 2004 through 2010, 231 patients underwent ALIF with (146) or without (85) plating. Eight patients lost to follow up were excluded from final evaluation. Patients' records were evaluated retrospectively for demographics, complications, and outcomes., Results: At a mean follow-up of 13.7 months (range, 1-108 mo), the mean Economic, Functional, and Total Prolo scores for ALIF patients were 4.23, 3.63, and 7.87, respectively. The mean Oswestry Disability Index (ODI) was 24%. At a mean follow-up of 11.2 months (range, 1-93 mo), the mean Economic, Functional, and Total Prolo scores for ALIFP patients were 4.28, 3.67, and 7.95, respectively. The mean ODI was 22.9%. There was no significant difference between rate of complications or Prolo scores or ODI between the 2 groups (t test). Neither diabetes, hypertension, smoking, sex, nor age older than 55 years was significantly related to whether patients had higher Prolo scores with or without plating. Patients with a normal body mass index and ALIF had significantly better Prolo Economic scores and total scores than patients with a normal body mass index and ALIFP (P=0.04 and 0.02, independent samples t test). Patients were also stratified by surgical indication for surgery, and there was no significant difference in Prolo scores or ODI for patients who underwent ALIF alone versus ALIFP., Conclusions: Even when stratified by indication for surgery, anterior plating does not seem to improve Prolo scores or ODI, suggesting that not all patients undergoing ALIF require plating.

Study Design: Retrospective case series., Objective: To identify the indications, techniques, and outcomes for instrumented fusion during thoracic discectomy., Summary of Background Data: Thoracic discectomy may require extensive bone removal to avoid spinal cord manipulation, but the indications and techniques for instrumented fusion during thoracic discectomy remain poorly delineated., Methods: The authors identified 220 consecutive patients who underwent thoracic discectomy between 1992 and 2012. Clinical and radiographic variables were compared between patients who underwent instrumented fusion and patients without instrumentation, and among surgical approaches utilized for discectomy., Results: Patient age for the entire cohort averaged 49±13.01 years, and mean clinical follow-up was 45 months (range, 1-218 mo). Patients underwent 226 thoracic discectomy procedures, including 48 thoracotomy, 136 thoracoscopy, and 42 posterolateral approaches. Seventy-eight patients required instrumented fusion and, compared with patients without instrumentation, were more likely to present with myelopathy (P<0.0001) and harbor giant (P=0.0012), calcified (P=0.019), or transdural (P=0.0004) herniated disks. Surgery with instrumentation resulted in greater blood loss (P<0.0001), longer hospital stay (P<0.0001), and a higher complication rate (22% vs. 9.9%), yet patients in both cohorts had similar rates of symptom resolution postoperatively. Of the patients who underwent thoracic discectomy without instrumentation, 3 (2.1%) developed delayed deformity or instability and required subsequent surgery for fixation and fusion at an average 6.3 months postoperatively (range, 4-8 mo). Patients who underwent instrumented fusion exhibited no nonunions or delayed deformity., Conclusions: Thoracic discectomy without fixation is a reasonable clinical option in carefully selected patients, but instrumented fusion is safe and effective in other patients. Indications for fixation and fusion are thus proposed.

We aimed to determine the clinical indications and surgical outcomes for thoracoscopic discectomy. Thoracic disc disease is a rare degenerative process. Thoracoscopic approaches serve to minimize tissue injury during the approach, but critics argue that this comes at the cost of surgical efficacy. Current reports in the literature are limited to small institutional patient series. We systematically identified all English language articles on thoracoscopic discectomy with at least two patients, published from 1994 to 2013 on MEDLINE, Science Direct, and Google Scholar. We analyzed 12 articles that met the inclusion criteria, five prospective and seven retrospective studies comprising 545 surgical patients. The overall complication rate was 24% (n=129), with reported complications ranging from intercostal neuralgia (6.1%), atelectasis (2.8%), and pleural effusion (2.6%), to more severe complications such as pneumonia (0.8%), pneumothorax (1.3%), and venous thrombosis (0.2%). The average reported postoperative follow-up was 20.5 months. Complete resolution of symptoms was reported in 79% of patients, improvement with residual symptoms in 10.2%, no change in 9.6%, and worsening in 1.2%. The minimally invasive endoscopic approaches to the thoracic spine among selected patients demonstrate excellent clinical efficacy and acceptable complication rates, comparable to the open approaches. Disc herniations confined to a single level, with small or no calcifications, are ideal for such an approach, whereas patients with calcified discs adherent to the dura would benefit from an open approach., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

Object: The sacroiliac joint (SIJ) and surgical intervention for treating SIJ pain or dysfunction has been a topic of much debate in recent years. There has been a resurgence in the implication of this joint as the pain generator for many patients experiencing low-back pain, and new surgical methods are gaining popularity within both the orthopedic and neurosurgical fields. There is no universally accepted gold standard for diagnosing or surgically treating SIJ pain. The authors systematically reviewed studies on SIJ fusion in the neurosurgical and orthopedic literature to investigate whether sufficient evidence exists to support its use., Methods: A literature search was performed using MEDLINE, Google Scholar, and OvidSP-Wolters Kluwer Health for all articles regarding SIJ fusion published from 2000 to 2014. Original, peer-reviewed, prospective or retrospective scientific papers with at least 2 patients were included in the study. Exclusion criteria included follow-up shorter than 1-year, nonsurgical treatment, inadequate clinical data as determined by 2 independent reviewers, non-English manuscripts, and nonhuman subjects., Results: A total of 16 peer-reviewed journal articles met the inclusion criteria: 5 consecutive case series, 8 retrospective studies, and 3 prospective cohort studies. A total of 430 patients were included, of whom 131 underwent open surgery and 299 underwent minimally invasive surgery (MIS) for SIJ fusion. The mean duration of follow-up was 60 months for open surgery and 21 months for MIS. SIJ degeneration/arthrosis was the most common pathology among patients undergoing surgical intervention (present in 257 patients [59.8%]), followed by SIJ dysfunction (79 [18.4%]), postpartum instability (31 [7.2%]), posttraumatic (28 [6.5%]), idiopathic (25 [5.8%]), pathological fractures (6 [1.4%]), and HLA-B27+/rheumatoid arthritis (4 [0.9%]). Radiographically confirmed fusion rates were 20%-90% for open surgery and 13%-100% for MIS. Rates of excellent satisfaction, determined by pain reduction, function, and quality of life, ranged from 18% to 100% with a mean of 54% in open surgical cases. For MIS patients, excellent outcome, judged by patients' stated satisfaction with the surgery, ranged from 56% to 100% (mean 84%). The reoperation rate after open surgery ranged from 0% to 65% (mean 15%). Reoperation rate after MIS ranged from 0% to 17% (mean 6%). Major complication rates ranged from 5% to 20%, with 1 study that addressed safety reporting a 56% adverse event rate., Conclusions: Surgical intervention for SIJ pain is beneficial in a subset of patients. However, with the difficulty in accurate diagnosis and evidence for the efficacy of SIJ fusion itself lacking, serious consideration of the cause of pain and alternative treatments should be given before performing the operation.

OBJECT The primary disadvantage of the posterior cervical approach for atlantoaxial stabilization after odontoidectomy is that it is conducted as a second-stage procedure. The goal of the current study is to assess the surgical feasibility and biomechanical performance of an endoscopic endonasal surgical technique for C1-2 fixation that may eliminate the need for posterior fixation after odontoidectomy. METHODS The first step of the study was to perform endoscopic endonasal anatomical dissections of the craniovertebral junction in 10 silicone-injected fixed cadaveric heads to identify relevant anatomical landmarks. The second step was to perform a quantitative analysis using customized software in 10 reconstructed adult cervical spine CT scans to identify the optimal screw entry point and trajectory. The third step was biomechanical flexibility testing of the construct and comparison with the posterior C1-2 transarticular fixation in 14 human cadaveric specimens. RESULTS Adequate surgical exposure and identification of the key anatomical landmarks, such as C1-2 lateral masses, the C-1 anterior arch, and the odontoid process, were provided by the endonasal endoscopic approach in all specimens. Radiological analysis of anatomical detail suggested that the optimal screw entry point was on the anterior aspect of the C-1 lateral mass near the midpoint, and the screw trajectory was inferiorly and slightly laterally directed. The custommade angled instrumentation was crucial for screw placement. Biomechanical analysis suggested that anterior C1-2 fixation compared favorably to posterior fixation by limiting flexion-extension, axial rotation, and lateral bending (p > 0.3). CONCLUSIONS This is the first study that demonstrates the feasibility of an endoscopic endonasal technique for C1-2 fusion. This novel technique may have clinical utility by eliminating the need for a second-stage posterior fixation operation in certain patients undergoing odontoidectomy.

Study Design: Case report and review of the literature., Objective: The aim of this study was to describe a novel approach for anterior cervical fixation, which uses cement augmentation in a patient with osteoporosis., Summary of Background Data: Osteoporotic bone presents a challenge for the treating spine surgeon, and techniques to overcome the difficulty of cervical spine fixation in these patients are lacking., Methods: A 75-year-old woman with osteoporosis presented with cervical myelopathy and was found to have multiple-level cervical stenosis and C3-4 degenerative instability. The patient underwent anterior cervical discectomy fusion and plating from C3-7, with vertebroplasty polymethylmethacrylate augmentation through the screw pilot holes. Because of the patient's grossly soft bone, she also underwent postoperative halo placement., Results: No cement extravasation was observed. The halo was removed after 3 months. At 6 months follow-up, the patient had full resolution of her myelopathy. Imaging showed the cervical interbody fusions to be healed at all levels, with no screw pullout or graft subsidence., Conclusions: This represents the first comprehensive description of successful cement augmentation during anterior cervical discectomy fusion and plating in a patient with osteoporosis, accomplishing both an increase in screw pullout strength and a decreased likelihood of graft subsidence. With further study, this technique may represent a viable treatment option in patients with osteoporosis requiring cervical decompression and fusion.

Object: Symptomatic herniated thoracic discs (HTDs) are rare, and patients infrequently require treatment of 2 or more disc levels. The authors assess the surgical management and outcomes of patients with multiple-level symptomatic HTDs., Methods: A retrospective review of a prospectively maintained database was performed of 220 consecutive patients treated surgically for symptomatic HTDs. Clinical and surgical results were compared between patients with single-level disease and patients with multiple-level disease and also among the different approaches used for surgical decompression., Results: Between 1992 and 2012, 56 patients (mean age 48 years; 26 male, 30 female) underwent 62 procedures for 130 HTDs. Forty-six patients (82%) had myelopathy, and 36 (64%) had thoracic radiculopathy; 24 patients had both conditions in varying degree. Symptom duration averaged 28 months. The surgical approach was dictated by disc size, consistency, and location. Twenty-three thoracotomy, 26 thoracoscopy, and 13 posterolateral procedures were performed. Five patients required a combination of approaches. Patients underwent 2-level (n = 44), 3-level (n = 7), 4-level (n = 4), or 5-level (n = 1) discectomies. Instrumented fusion was performed in 36 patients (64%). Thirteen patients harbored 19 additional discs, which were deemed asymptomatic/nonoperative. The mean hospital stay was 6.5 days. Complete disc resection was verified with postoperative imaging in every patient. The procedural complication rate was 23%, and the nature of complications differed based on approach. No patients had surgery-related spinal cord injury or new myelopathy. At a mean follow-up of 48 months, myelopathy and radiculopathy had resolved or improved at a rate of 85% and 92%, respectively. Using a general linear model, preoperative symptom duration (p = 0.037) and perioperative hospital length of stay (p = 0.004) emerged as negative predictors of myelopathy improvement. Most patients (96%) were satisfied with the surgical results. Compared with 164 patients who underwent single-level HTD decompression, patients requiring surgery for multiple-level HTDs were more often myelopathic (p = 0.012). Surgery for multiple-level HTDs was more likely to require a thoracotomy approach (p = 0.00055) and instrumented fusion (p < 0.0001) and resulted in greater blood loss (p = 0.0036) and higher complication rates (p = 0.0069). The rates of resolution for myelopathy (p = 0.24) and radiculopathy (p = 1.0), however, were similar between the 2 patient groups., Conclusions: The management of multiple-level symptomatic HTDs is complex, requiring individualized clinical decision making. The surgical approaches must be selected to minimize manipulation of the compressed thoracic spinal cord, and a patient may require a combination of approaches. Excellent surgical results can be achieved in this unique and challenging patient population.

Background: : Endoscopic endonasal approaches to the craniovertebral junction and clivus, which are increasingly performed for ventral skull base pathology, may require disruption of the occipitocondylar joint., Objective: : To study the biomechanical implications at the craniovertebral junction of progressive unilateral condylectomy as would be performed through an endonasal exposure., Methods: : Seven upper cervical human cadaveric specimens (C0-C2) underwent nondestructive biomechanical flexibility testing during flexion-extension, axial rotation, and lateral bending at C0-C1 and C1-C2. Each specimen was tested intact, after an inferior one-third clivectomy, and after stepwise unilateral condylectomy with an anterior approach. Angular range of motion (ROM), lax zone, and stiff zone were determined and compared with the intact state., Results: : At C0-C1, mobility during flexion-extension and axial rotation increased significantly with progressive condylectomy. ROM increased from 14.3 ± 2.7° to 20.4 ± 5.2° during flexion and from 6.7 ± 3.5° to 10.8 ± 3.0° during right axial rotation after 75% condyle resection (P < .01). At C1-C2, condylectomy had less effect, with ROM increasing from 10.7 ± 2.0° to 11.7 ± 2.0° during flexion, 36.9 ± 4.8° to 37.1 ± 5.1° during right axial rotation, and 4.3 ± 1.9° to 4.8 ± 3.3° during right lateral bending (P = NS). Because of marked instability, the 100% condylectomy condition was untestable. Changes in ROM were a result of changes more in the lax zone than in the stiff zone., Conclusion: : Lower-third clivectomy and unilateral anterior condylectomy as would be performed in an endonasal approach cause progressive hypermobility at the craniovertebral junction. On the basis of biomechanical criteria, craniocervical fusion is indicated for patients who undergo > 75% anterior condylectomy.

We present a 16-year-old male patient with Marfan's syndrome who presented with quadriparesis from a Type I Chiari malformation (CM) with basilar invagination and a syrinx. The condition resolved after transoral odontoidectomy and occipitocervical fusion without posterior decompression of the CM. Thus, ventral decompression alone can resolve a cervical syrinx in patients with compression of the foramen magnum., (Copyright © 2012 Elsevier Ltd. All rights reserved.)

Cavernous malformations (CMs) are found throughout the CNS but are relatively uncommon in the spine. In this report, the authors describe a giant CM with the imaging appearance of an aggressive, invasive, expansive tumor in the cervical spine. The intradural extramedullary portion of the tumor originated from a cervical nerve root; histologically, the lesion was identified as an intraneural CM. Most of the tumor extended into the paraspinal tissues. The tumor was also epidural, intraosseous, and osteolytic and had completely encased cervical nerve roots, peripheral nerves, branches of the brachial plexus, and the vertebral artery on the right side. It became symptomatic during the puerperal period. Gross-total resection was achieved using staged operative procedures, complex dural reconstruction, spinal fixation, and fusion. Clinical, radiographic, and histological details, as well as a discussion of the relevant literature, are provided.

Background and Importance: To describe a novel nerve-sparing technique for the resection of intercostal nerve schwannomas. This case demonstrates that intercostal neuralgia can be caused by intercostal schwannomas and that it can be relieved by their removal., Clinical Presentation: A young woman with schwannomatosis had progressively worsening intercostal neuralgia caused by compression of the intercostal nerve against the rib by tandem intercostal schwannomas. After the tumors were removed, her symptoms were completely relieved. A thoracoscopic technique was used to define the involved fascicles and to facilitate removal of the tumors while sparing the uninvolved nerve., Conclusion: The patient's radicular pain was relieved completely by the tumor resection. Thoracoscopic surgery offers a safe and minimally invasive technique for removal of intercostal schwannomas and is a valid alternative to open thoracotomy. Removal of thoracic schwannomas can relieve intercostal neuralgia.

Object: Schwannomas occupying the craniocervical junction (CCJ) are rare and usually originate from the jugular foramen, hypoglossal nerves, and C-1 and C-2 nerves. Although they may have different origins, they may share the same symptoms, surgical approaches, and complications. An extension of these lesions along the posterior fossa cisterns, foramina, and spinal canal--usually involving various cranial nerves (CNs) and the vertebral and cerebellar arteries--poses a surgical challenge. The primary goals of both surgical and radiosurgical management of schwannomas in the CCJ are the preservation and restoration of function of the lower CNs, and of hearing and facial nerve function. The origins of schwannomas in the CCJ and their clinical presentation, surgical management, adjuvant stereotactic radiosurgery, and outcomes in 36 patients treated at Barrow Neurological Institute (BNI) are presented., Methods: Between 1989 and 2009, 36 patients (mean age 43.6 years, range 17-68 years) with craniocervical schwannomas underwent surgical resection at BNI. The records were reviewed retrospectively regarding clinical presentation, radiographic assessment, surgical approaches, adjuvant therapies, and follow-up outcomes., Results: Headache or neck pain was present in 72.2% of patients. Cranial nerve impairments, mainly involving the vagus nerve, were present in 14 patients (38.9%). Motor deficits were found in 27.8% of the patients. Sixteen tumors were intra- and extradural, 15 were intradural, and 5 were extradural. Gross-total resection was achieved in 25 patients (69.4%). Adjunctive radiosurgery was used in the management of residual tumor in 8 patients; tumor control was ultimately obtained in all cases., Conclusions: Surgical removal, which is the treatment of choice, is curative when schwannomas in the CCJ are excised completely. The far-lateral approach and its variations are our preferred approaches for managing these lesions. Most common complications involve deficits of the lower CNs, and their early recognition and rehabilitation are needed. Stereotactic radiosurgery, an important tool for the management of these tumors as adjuvant therapy, can help decrease morbidity rates.

Object: Thoracoscopy may be used in place of thoracotomy to resect intrathoracic neoplasms such as paraspinal neurogenic tumors. Although these tumors are rare, they account for the majority of tumors arising in the posterior mediastinum., Methods: A database was maintained of all patients undergoing thoracoscopic surgery for tumors. The authors analyzed the presenting symptoms, pathological diagnoses, and outcomes of 26 patients (7 males and 19 females, mean age 37.2 years) who were treated for intrathoracic tumors via thoracoscopy between January 1995 and May 2009. Fourteen patients were diagnosed incidentally (54%). Five patients (19%) presented with dyspnea or shortness of breath, 4 (15%) with pain, 1 (4%) with pneumonia, 1 (4%) with hoarseness, and 1 (4%) with Horner syndrome., Results: Pathology demonstrated schwannomas in 20 patients (77%). Other diagnoses included ganglioneurofibroma, paraganglioma, epithelioid angiosarcoma, benign hemangioma, benign granular cell tumor, and infectious granuloma. One patient required conversion to open thoracotomy due to pleural scarring to the tumor. One underwent initial laminectomy due to intraspinal extension of the tumor. Gross-total resection was obtained in 25 cases (96%). The remaining patient underwent biopsy followed by radiation therapy. The mean surgical time was 2.5 hours, and the mean blood loss was 243 ml. The mean duration of chest tube insertion was 1.3 days, and the mean length of hospital stay was 3.0 days. Cases that were treated in the second half of the cohort were more often diagnosed incidentally, performed in less time, and had less blood loss than those in the first half of the cohort. There was 1 case of permanent treatment-related morbidity (mild Horner syndrome). All previously employed patients were able to return to work (mean clinical follow-up 43 months). There were no recurrences (mean imaging follow-up 54 months)., Conclusions: Endoscopic transthoracic approaches can reduce approach-related soft-tissue morbidity and facilitate recovery by preserving the normal tissues of the chest wall, by avoiding rib retraction and muscle transection, and by reducing postoperative pain. This less invasive approach thus shortens hospital stay and recovery time.

Background: Hyperhidrosis (HH) profoundly affects a patient's well-being., Objective: We report indications and outcomes of 322 patients treated for HH via thoracoscopic sympathectomy or sympathotomy at the Barrow Neurological Institute., Methods: A prospectively maintained database of all patients who underwent sympathectomy or sympathotomy between 1996 and 2008 was examined. Additional follow-up was obtained in clinic, by phone, or by written questionnaire., Results: A total of 322 patients (218 female patients) had thoracoscopic treatment (mean age 27.6 years; range, 10-60 years). Mean follow-up was 8 months. Presentations included HH of the palms (43 patients, 13.4%), axillae (13 patients, 4.0%), craniofacial region (4 patients, 1.2%), or some combination (262 patients, 81.4%). Sympathectomy and sympathotomy were equally effective in relieving HH. Palmar HH resolved in 99.7% of patients. Axillary or craniofacial HH resolved or improved in 89.1% and 100% of cases, respectively. Hospital stay averaged 0.5 days. Ablating the sympathetic chain at T5 increased the incidence of severe compensatory sweating (P = .0078). Sympathectomy was associated with a significantly higher incidence of Horner's syndrome compared with sympathotomy (5% vs 0.9%, P = .0319). Patients reported satisfaction and willingness to undergo the procedure again in 98.1% of cases., Conclusion: Thoracoscopic sympathectomy is effective and safe treatment for severe palmar, axillary, and craniofacial HH. Ablating the T5 ganglion tends to increase the severity of compensatory sweating. Sympathectomy led to a higher incidence of ipsilateral Horner's syndrome compared with sympathotomy.

Object: Palmar, axillary, and plantar hyperhidrosis is often socially, emotionally, and physically disabling for adolescents. The authors report surgical outcomes in all adolescents treated for palmar hyperhidrosis via bilateral thoracoscopic sympathectomy at the Barrow Neurological Institute by the senior author., Methods: A prospectively maintained database of all adolescent patients undergoing bilateral thoracoscopic sympathectomy between 1998 and 2006 (inclusive) was reviewed. Additional follow-up was obtained as needed in clinic or by phone or written questionnaire., Results: Fifty-four patients (40 females) undergoing bilateral procedures were identified. Their mean age was 15.4 years (range 10-17 years). Average follow-up was 42 weeks (range 0.2-143 weeks). Hyperhidrosis involved the palms alone in 10 patients; the palms and axilla in 6 patients; the palms and plantar surfaces in 17 patients; and the palms, axilla, and plantar surfaces in 21 patients. Palmar hyperhidrosis resolved completely in 98.1% of the patients. Resolution or improvement of symptoms was seen in 96.3% of patients with axillary and 71.1% of those with plantar hyperhidrosis. Hospital stay averaged 0.37 days with 68.5% of patients discharged the day of surgery. One patient experienced brief intraoperative asystole that resolved with medications and had no long-term sequelae. Otherwise, no serious intraoperative complications occurred. No patient required chest tube drainage. The percentage of patients who reported satisfaction and willingness to undergo the procedure again was 98.1%., Conclusions: Biportal, bilateral thoracoscopic sympathectomy is an effective and low-morbidity treatment for severe palmar, axillary, and plantar hyperhidrosis.

Objective: Anterior cervical discectomy and fusion with plating is a common procedure performed for cervical spondylosis by spine surgeons. However, data on procedures involving 4 disc spaces are lacking. We report the outcomes of patients who underwent 4-level anterior cervical discectomy and fusion with plating at a single institution., Methods: Between 1997 and 2006, 34 patients (19 females, 15 males; mean age, 58 years; age range, 38-83 years) underwent 4-level anterior cervical discectomy and fusion with plating based on a surgical database search. Only patients undergoing surgery at 4 contiguous disc levels were included. Data were collected in a retrospective fashion. Patients' demographics, symptoms, neurologic findings, and radiographic findings at admission were recorded. Long-term clinical and radiographic outcomes at last follow-up were analyzed., Results: Twenty-nine patients (85%) underwent anterior cervical discectomy and fusion with plating at C3-C7. Sixteen patients presented with neurologic deficits, of which 14 (88%) improved. None worsened after surgery. Minor complications occurred in 26 patients, including transient dysphagia in 18 (53%) and hoarseness in 3 (9%). Radiographic outcomes were available in 27 patients (median follow-up, 15 months; range, 4-71 months). The overall fusion rate was 92.6%. Stable fibrous nonunions were present in 2 patients; the chance of nonunion was 1.9% per level and 7% per patient. Adjacent-level disease occurred in 2 patients., Conclusion: In carefully selected patients, 4-level anterior cervical discectomy and fusion with plating can be associated with high rates of fusion. The technique is safe and effective for managing multilevel cervical spondylotic myelopathy and may obviate the need for circumferential procedures.

Occipitoatlantal dislocation (OAD) can be devastating. This injury may be fatal in many cases, but more survivors are reported because of improvements in diagnosis and treatment. This article describes the diagnosis and treatment of OAD. To diagnose and treat OAD appropriately, neurosurgeons must have a detailed understanding of the anatomy of the craniocervical junction. Various radiographic criteria are used to establish the diagnosis of OAD. A destabilizing injury such as OAD requires surgical fixation. Many surgical techniques are available for fixation of the craniocervical junction. Future studies will continue to refine the diagnostic criteria for OAD and to develop improved methods for craniocervical stabilization.

Objective: To compare the biomechanics of costotransverse process screw fixation with those of pedicle screw fixation in a cadaveric model of the upper thoracic spine., Methods: Ten human thoracic spines were instrumented across the T3-T4 segment with costotransverse and pedicle screws. Nonconstraining pure moments (maximum, 6.0 Nm) were applied to induce flexion, extension, lateral bending, and axial rotation. The range of motion, lax zone, and stiff zone were determined in each specimen in the normal state, after 3-column destabilization, and after instrumentation. After flexibility testing was completed, axial screw pull-out strength was assessed., Results: In all directions of loading, both fixation techniques significantly decreased lax zone and range of motion at T3-T4 compared with the destabilized state (P < .001). During all loading modes except lateral bending, pedicle screw fixation allowed significantly less range of motion than costotransverse screw fixation. Pedicle screws provided 62% greater resistance to axial pull-out than costotransverse screws., Conclusion: The costotransverse screw technique seems to provide only moderately stiff fixation of the destabilized thoracic spine. Pedicle screw fixation seems to have more favorable biomechanical properties. These data suggest that the costotransverse process construct is better used as a salvage procedure rather than as a primary fixation strategy.

Spinal meningeal melanocytomas are rare lesions that are histologically benign and can behave aggressively, with local infiltration. The authors present their experience with intramedullary spinal cord melanocytomas consisting of 3 cases, which represents the second largest series in the literature. A retrospective chart review was performed following identification of all spinal melanocytomas treated at the author's institution, based on information obtained from a neuropathology database. The charts were reviewed for patient demographics, surgical procedure, clinical outcome, and long-term tumor progression. Three patients were identified in whom spinal melanocytoma had been diagnosed between 1989 and 2006. The patients' ages were 37, 37, and 48 years, and the location of their tumor was C1-3, T9-10, and T-12, respectively. All 3 had complete resection with no adjuvant radiotherapy during follow-up periods of 16, 38, and 185 months, respectively. One patient demonstrated a recurrence 29 months after resection and the other 2 patients have demonstrated asymptomatic recurrences on imaging studies obtained at 16 and 38 months following resection. With these cases added to the available literature, the evidence strongly suggests that complete resection is the treatment of choice for spinal melanocytomas. Even with complete resection, recurrences are common and close follow-up is needed for the long term in these patients. Radiation therapy should be reserved for those cases in which complete resection is not possible or in which there is recurrence.

Since the Food and Drug Administration approved the Babgy-Kuslich BAK cage for anterior lumbar interbody fusion (ALIF), various threaded interbody fusion devices have been introduced. Bone dowels offer several theoretical advantages over cages with regard to stress shielding; the purpose of this study was to assess the efficacy of bone dowels in interbody fusion. All patients undergoing ALIF performed by the senior author between 1998 and 2001 were retrospectively reviewed. Patients' preoperative and postoperative neurologic status, functional status, and both back and radicular pain were assessed according to a previously published outcome measure. Between 1998 and 2000, 23 patients underwent ALIF with cortical femoral allograft bone dowels. One patient underwent simultaneous bone dowel and titanium cage placements and was therefore excluded from further analysis. The 22 remaining patients underwent a total of 33 fused segments; of these, 21 patients were available for follow-up. Mean clinical follow-up was 30.6 months. Mean imaging follow-up was 21 months. There were 5 instances of radiographic nonunion (3 symptomatic and 2 asymptomatic). The incidence of technical failures and complications related to the bone dowels was 17%. Bone dowels failed and caused symptoms only in patients with a stand-alone ALIF. There were no clinical failures in patients treated with supplemental anterior or posterior spinal fixation. These data demonstrate that marginal fusion rates and functional success rates can be achieved using stand-alone bone dowels for ALIF. The clinical success and fusion rates are significantly higher if ALIF dowels are shielded from stress with rigid spinal instrumentation.

Background Context: Locking posterior instrumentation in the cervical spine can be attached using 1) pedicle screws, 2) lateral mass screws, or 3) laminar hooks. This order of options is in order of decreasing technical difficulty and decreasing depth of fixation, and is thought to be in order of decreasing stability., Purpose: We sought to determine whether substantially different biomechanical stability can be achieved in a two-level construct using pedicle screws, lateral mass screws, or laminar hooks. Secondarily, we sought to quantify the differential and additional stability provided by an anterior plate., Study Design: In vitro biomechanical flexibility experiment comparing three different posterior constructs for stabilizing the cervical spine after three-column injury., Methods: Twenty-one human cadaveric cervical spines were divided into three groups. Group 1 received lateral mass screws at C5 and C6 and pedicle screws at C7; Group 2 received lateral mass screws at C5 and C6 and laminar hooks at C7; Group 3 received pedicle screws at C5, C6, and C7. Specimens were nondestructively tested intact, after a three-column two-level injury, after posterior C5-C7 rod fixation, after two-level discectomy and anterior plating, and after removing posterior fixation. Angular motion was recorded during flexion, extension, lateral bending, and axial rotation. Posterior hardware was subsequently failed by dorsal loading., Results: Laminar hooks performed well in resisting flexion and extension but were less effective in resisting lateral bending and axial rotation, allowing greater range of motion (ROM) than screw constructs and allowing a significantly greater percentage of the two-level ROM to occur across the hook level than the screw level (p<.03). Adding an anterior plate significantly improved stability in all three groups. With combined hardware, Group 3 resisted axial rotation significantly worse than the other groups. Posterior instrumentation resisted lateral bending significantly better than anterior plating in all groups (p<.04) and resisted flexion and axial rotation significantly better than anterior plating in most cases. Standard deviation of the ROM was greater with anterior than with posterior fixation. There was no significant difference among groups in resistance to failure (p=.74)., Conclusions: Individual pedicle screws are known to outperform lateral mass screws in terms of pullout resistance, but they offered no apparent advantage in terms of construct stability or failure of whole constructs. Larger standard deviations in anterior fixation imply more variability in the quality of fixation. In most loading modes, laminar hooks provided similar stability to lateral mass screws or pedicle screws; caudal laminar hooks are therefore an acceptable alternative posteriorly. Posterior two-level fixation is less variable and slightly more stable than anterior fixation. Combined instrumentation is significantly more stable than either anterior or posterior alone.

Background Context: The technique of occipitocervical fusion using a threaded contoured rod attached with sublaminar wires to the occiput and upper cervical vertebrae is widely used throughout the world and has been clinically proven to provide effective fixation of the destabilized spine. However, this system has some disadvantages in maintaining stability, especially at C1-C2 because of the large amount of axial rotation at this level. In some clinical situations such as fracture of the C1 lamina, C1 laminectomy, and excessively lordotic curvature, it is not always possible to wire C1 directly into the construct. In such cases, combination of other stabilization methods that include C1 indirectly can be used to achieve a reliable posterior internal fixation., Purpose: Primarily, to evaluate whether a contoured rod construct in which C1 is indirectly included using C1-C2 transarticular screws is biomechanically equivalent to a standard, fully wired contoured rod construct. Secondarily, to evaluate the biomechanical benefit of adding C1-C2 transarticular screws to a fully wired contoured rod construct., Study Design: Repeated-measures nondestructive in vitro biomechanical testing of destabilized cadaveric human occipitocervical spine specimens., Methods: Six human cadaveric specimens from the occiput to C3 were studied. Angular and linear displacement data were recorded while nonconstraining nondestructive loads were applied. Three methods of fixation were tested: contoured rod incorporating C1 with and without transarticular screws and contoured rod with transarticular screws without incorporating C1., Results: All three constructs reduced motion to well within normal range. In contoured rod constructs with C1 wired, addition of transarticular screws slightly but significantly improved stability. In constructs with transarticular screws, incorporation of C1 into the contoured rod wiring did not improve stability significantly., Conclusions: Adding C1-C2 transarticular screws to a wired contoured rod construct where C1 is included only slightly improves stability. As the absolute reduction in motion from adding transarticular screws is small (<1 degree), it is doubtful whether any enhanced fusion from this additional procedure outweighs the surgical risks. However, transarticular screws provide an effective alternate method to fixate C1 when the posterior arch of C1 is absent or has been fractured.

Object: Although rare, traumatic occipitoatlantal dislocation (OAD) injuries are associated with a high mortality rate. The authors evaluated the imaging and clinical factors that determined treatment and were predictive of outcomes, respectively, in survivors of this injury., Methods: The medical records and imaging studies obtained in 33 patients with OAD were reviewed retrospectively. Clinical factors that predicted outcomes, especially neurological injury at presentation and imaging findings, were evaluated. The most sensitive method for the diagnosis of OAD was the measurement of basion axial-basion dens interval on computed tomography (CT) scanning. Five patients with severe traumatic brain injuries (TBIs) were not treated and subsequently died. Of the 28 patients in whom treatment was performed, 23 underwent fusion and five were fitted with an external orthosis. Abnormal findings of the occipitoatlantal ligaments on magnetic resonance (MR) imaging, associated with no or questionable abnormalities on CT scanning, provided the rationale for nonoperative treatment. Of the 28 patients treated for their injuries, perioperative death occurred in five, three of whom had presented with severe neurological injuries. The mortality rate was highest in patients with a TBI at presentation. The mortality rate was lower in patients presenting with a spinal cord injury, but in this group there was a higher rate of persistent neurological deficits., Conclusions: The spines in patients with CT-documented OAD are most likely unstable and need surgical fixation. In patients for whom CT findings are normal and MR imaging findings suggest marginal abnormalities, nonoperative treatment should be considered. The best predictors of outcome were severe brain or upper cervical injuries at initial presentation.

Introduction: Camptomelic dysplasia (CD) is a rare autosomal dominant skeletal dysplasia classically characterized by bent bones of the extremities, tracheobronchial narrowing, thoracic kyphoscoliosis, and various degrees of phenotypic sex reversal. Most patients die of complications in infancy, although long-term survivors have been reported., Case Report: We report a case of CD complicated by incomplete ossification of the cervical vertebral pedicles, resulting in congenital cervical instability and kyphosis. Closed reduction was performed, and the patient was fitted with a customized cervical orthosis., Finding: He subsequently developed a complete spinal cord injury at the kyphotic level. This underscores the grim prognosis associated with neonatal cervical spinal instability.

The management of spinal meningiomas with extensive involvement of the dura mater is controversial. The principal difficulty in performing a resection is the potential for complications associated with this approach. The authors present the case of a pregnant 35-year-old woman in whom bilateral lower-extremity numbness, weakness, gait ataxia, and myelopathy developed. Magnetic resonance imaging showed a recurrent thoracic meningioma with extensive infiltration of the dura mater. Durectomy, complete resection, and reconstruction were performed. The patient has not experienced a recurrence 21 months after her treatment. This case illustrates that thoracic spinal meningiomas with extensive dural involvement can be resected safely with a complete durectomy. The novel dural reconstruction involving the implantation of a fascia lata and bovine pericardium allograft is an effective way to reconstruct the dura to create an adequate barrier to cerebrospinal fluid.

Object: The risk factors of halo fixation in elderly patients have never been analyzed. The authors therefore retrospectively reviewed data obtained in the treatment of such cases., Methods: A discharge database was searched for patients 70 years of age or older who had undergone placement of a halo device. In a search of cases managed between April 1999 and February 2005, data pertaining to 53 patients (mean age 79.9 years [range 70-97 years]) met these criteria. Forty-one patients were treated for traumatic injuries. Ten patients had deficits ranging from radiculopathy to quadriparesis, and 43 had no neurological deficit. Adequate follow-up material was available in 42 patients (mean treatment duration 91 days). Halo immobilization was the only treatment in 21 patients, and adjunctive surgical fixation was undertaken in the other 21 patients. There were 31 complications in 22 patients: respiratory distress in four patients, dysphagia in six, and pin-related complications in 10. Eight patients died; in two of these cases, the cause of death was clearly unrelated to the halo brace. The other six patients died of respiratory failure and cardiovascular collapse (perioperative mortality rate 14%). Three patients who died had sustained acute trauma and three had undergone surgical stabilization., Conclusions: External halo fixation can be used safely to treat cervical instability in elderly patients. The high complication rate in this population may reflect the significant incidence of underlying disease processes.

Background Context: Thoracic hyperextension fracture-dislocation is a rare pattern of traumatic spinal injury, typically associated with gross spinal instability and severe neurological deficit. These extremely unstable injuries require internal fixation despite their potentially benign clinical presentation., Purpose: We present a patient with a thoracic distraction injury who remained neurologically intact., Methods: The patient underwent thoracoscopic reduction and anterior fixation of the thoracic spine using a paired screw-rod construct., Results: Postoperatively, the patient remained neurologically intact and had no complications related to his thoracic fixation and fusion. Follow-up radiographs showed maintenance of thoracic alignment and bony fusion., Conclusions: The endoscopic approach to the anterior thoracic spine was an excellent treatment option for this thoracic distraction injury.

Study Design: Human lumbosacral cadaveric specimens were tested in an in vitro biomechanical flexibility experiment using physiologic loads in 5 sequential conditions., Objective: To determine the biomechanical differences between anterior lumbar interbody fusion (ALIF) using cylindrical threaded cages alone or supplemented with an anterior screw-plate or posterior pedicle screws-rods., Summary of Background Data: Clinically and biomechanically, stand-alone ALIF performs modestly in immobilizing the unstable spine. Pedicle screws improve fixation stiffness significantly, but supplementary anterior instrumentation has not been studied., Methods: There were 7 specimens tested: (1) intact, (2) after discectomy and facetectomy to induce moderate rotational and translational hypermobility, (3) with 2 parallel ALIF cages, (4) with cages plus a triangular anterior screw-plate, and (5) with cages plus pedicle screws-rods. Pure moments without preload induced flexion, extension, lateral bending, and axial rotation; linear shear forces induced anteroposterior translation. Angular and linear motions were measured stereophotogrammetrically, and range of motion (ROM) and stiffness were quantified., Results: Compared to the destabilized spine, interbody cages alone reduced ROM by 77% during flexion, 53% during extension, 60% during lateral bending, 69% during axial rotation, and 71% during anteroposterior shear (P < 0.001, analysis of variance/Fisher least significant difference). Addition of an anterior plate or pedicle screws-rods, respectively, further reduced ROM by 8% or 13% during flexion (P = 0.21), 21% or 28% during extension (P = 0.15), 5% or 25% during lateral bending (P = 0.04), 11% or 18% during axial rotation (P = 0.13), and 18% or 18% during anteroposterior shear (P = 0.17). Compared to stand-alone ALIF, both the anterior screw-plate and pedicle screw-rod fixation reduced vertebral ROM to less than 1.2 degrees of rotation and less than 0.1 mm of translation., Conclusions: The anterior screw-plate and pedicle screws-rods both substantially reduced ROM and increased stiffness compared to stand-alone interbody cages. There was no significant difference in the amount by which the supplementary fixation devices limited flexion, extension, axial rotation, or anteroposterior shear; pedicle screws-rods better restricted lateral bending.

Object: A flexibility experiment using human cadaveric thoracic spine specimens was performed to determine biomechanical differences among thoracolumbar two-screw plate, single-screw plate, and dual-rod systems. A secondary goal was to investigate differences in the ability of the systems to stabilize the spine after a one- or two-level corpectomy., Methods: The authors evaluated 21 cadaveric spines implanted with a titanium mesh cage and three types of anterior thoracolumbar supplementary instrumentation after one-level thoracic corpectomies. Pure moments were applied quasistatically while three-dimensional motion was measured optoelectronically. The lax zone, stiff zone, and range of motion (ROM) were measured during flexion, extension, left and right lateral bending, and left and right axial rotation. Corpectomies were expanded to two levels, and testing was repeated with longer hardware. Biomechanical testing showed that the single-bolt plate system was no different from the dual-rod system with two screws in limiting ROM. The single-bolt plate system performed slightly better than the two-screw plate system. Across the same two levels, there was an average of 19% more motion after a two-level corpectomy than after a one-level corpectomy. In general, however, the difference across the different loading modes was insignificant., Conclusions: Biomechanically, the single-screw plate system is equivalent to a two-screw dual-rod and a two-screw plate system. All three systems performed similarly in stabilizing the spine after one- or two-level corpectomies.

Background: An alternative approach for the treatment of the degenerative or unstable lumbar spine using retroperitoneal lateral LIF with anterolateral screw-plate or screw-rod fixation is introduced. Special attention is given to application of this procedure in patients who have undergone prior lumbar surgery., Methods: Between 1998 and 2001, 14 patients underwent lateral LIF with anterolateral instrumentation to treat degenerative foraminal stenosis or spondylolisthesis. Eleven patients (79%) had undergone prior posterior lumbar surgery, 7 of whom were also fused at that time. All patients first presented with mechanical back pain, radicular pain, or both. The mean follow-up was 21 months (range, 8 to 36 months)., Results: Radicular pain and mechanical back pain significantly improved in 71% and 54% of patients, respectively. Of the 9 patients with preoperative neurological deficits, 7 were intact or had improved at their follow-up examination. One patient developed postoperative radiculopathy contralateral to his original symptoms. Radiography confirmed good positioning of the hardware and evidence of fusion in all 14 patients. No major complications occurred., Conclusions: Retroperitoneal lateral LIF with anterolateral instrumentation is an attractive alternative for the treatment of the degenerative or unstable lumbar spine in the absence of significant spinal stenosis. This approach is particularly useful for treating spondylolisthesis or degenerative foraminal stenosis in the postoperative lumbar spine.

Study Design: An animal model of posterolateral intertransverse process spine fusion was used., Objectives: To investigate whether recombinant human bone morphogenetic protein-2 (rhBMP-2) can overcome the adverse effects of radiation treatment (RT) on spine fusion., Summary of Background Data: Spinal metastases are common. Some of these patients are candidates for spinal cord decompression and vertebral reconstruction; however, radiation has significant adverse effects on bone healing., Methods: A posterolateral fusion model was used with rhBMP-2 or iliac crest bone graft (ICBG). Eighty one-year-old rabbits were divided into eight groups: 1) RT 14 days before surgery, rhBMP-2; 2) RT 14 days before surgery, ICBG; 3) RT 2 days after surgery, rhBMP-2; 4) RT 2 days after surgery, ICBG; 5) RT 14 days after surgery, rhBMP-2; 6) RT 14 days after surgery, ICBG; 7) no RT, rhBMP-2; 8) no RT, ICBG. Animals were killed approximately 35 days after surgery. Manual palpation was the definitive test of fusion. Biomechanical and histologic assessments were also performed., Results: All rhBMP-2 groups had significantly greater fusion rates versus respective ICBG control groups: 1 (86%) versus 2 (0%) (P = 0.005), 3 (100%) versus 4 (0%) (P < 0.0001), 5 (100%) versus 6 (0%) (P < 0.0001), and 7 (100%) versus 8 (60%) (P = 0.003). Stiffness and ultimate strength did not differ significantly between the experimental and control groups. Histologic assessment confirmed new bone formation in the fusion masses from rhBMP-2 groups., Conclusions: Use of rhBMP-2 produced a significantly greater rate of fusion compared with ICBG in a previously radiated area in an animal model, without the morbidity of ICBG harvesting and without the risk of inadvertently using autograft contaminated by micrometastases.

Background: This study compared porcine and human thoracic spine anatomies for a better understanding of how structures encountered during thoracoscopy differ between training with a porcine model and actual surgery in humans., Methods: Parameters were measured including vertebral body height, width, and depth; disc height; rib spacing; spinal canal depth and width; and pedicle height and width., Results: Although most porcine vertebral structures were smaller, porcine pedicle height was significantly greater than that of humans because the porcine pedicle houses a unique transverse foramen. The longus colli and psoas attach, respectively, to T5 and T13 in swine and to T3 and T12 in humans. In swine, the azygos vein generally was absent. The intercostal veins drained into the hemiazygos vein., Conclusions: Several thoracoscopically relevant anatomic differences between human and porcine spinal anatomies were identified. A thoracoscopic approach in a porcine model probably is best performed from the right side. The best general working area is between T6 and T10.

Occipitoatlantal dislocation and atlantoaxial vertical distraction are caused by similar mechanisms, and few individuals survive these injuries. It is hypothesized that the injurious vertical force manifests as a traumatic lesion at different levels of the same ligamentous complex. The authors report the cases of two patients who presented with this combined lesion, describe surgical alternatives for stabilization, and introduce a new technique that combines the use of transarticular screws in a "dual" construct, without involving the unaffected spine.

Object: The authors evaluated the clinical and surgical outcomes obtained in patients with giant herniated thoracic discs (HTDs), defined as occupying more than 40% of the spinal canal. Surgery-related considerations and functional outcomes in patients with small- and medium-sized HTDs were compared., Methods: The authors reviewed 140 cases of surgically treated HTDs, 20 (14%) of which were giant. Before and after surgery, all patients underwent computerized tomography myelography, magnetic resonance imaging, or both. Functional outcomes were assessed using the Frankel grading system preoperatively, immediately after surgery, and at long-term follow-up examination. The results observed in patients with giant HTDs were compared with those with small- and medium-sized HTDs. The mean overall follow-up period was 2.6 years. Sixty-six patients (47%) presented with myelopathy, including 19 (95%) with a giant HTD. Of the latter, 16 (80%) underwent anterior, eight thoracoscopic, and eight open thoracotomy approaches. Four patients (20%) with laterally oriented giant HTDs within the spinal canal underwent surgery via a posterolateral approach. Based on analysis of long-term follow-up data, 53% of patients with giant HTDs improved neurologically by one Frankel grade. Progression of myelopathy was arrested in 42%, and in 5% the Frankel grade worsened by one. In patients with small- and medium-sized HTDs, the Frankel grade improved by one in 77%, stabilized in 23%, and worsened in 0%. Patients with giant HTDs who underwent thoracoscopic surgery had worse short- and long-term functional outcomes than those in whom open thoracotomy was performed., Conclusions: Patients with giant HTDs presented more frequently with myelopathy and experienced worse functional outcomes than those with smaller HTDs. Based on their experience, the authors recommend open thoracotomy rather than thoracoscopy for the treatment of midline giant HTDs.

Study Design: Unilateral facet dislocation was created in human cadaveric cervical spines. Specimens were sequentially instrumented with posterior or anterior screws and plates, and studied biomechanically., Objective: To determine the biomechanical differences between anterior and posterior fixation for stabilization of a reduced unilateral cervical facet dislocation., Summary of Background Data: Although previous studies have compared anterior to posterior instrumentation, no data exist on the biomechanics of either type of stabilization after this particular injury., Methods: In 6 human cadaveric cervical spine segments, a reproducible unilateral facet dislocation was created and then unlocked (reduced). Nondestructive torques were applied to specimens that were intact, injured-reduced, fixated using posterior nonlocking lateral mass plates, and fixated using a bone graft plus an anterior nonlocking plate. Flexion, extension, lateral bending, and axial rotation were measured stereophotogrammetrically., Results: Lateral mass plating was more effective than anterior plating in limiting motion after reduction of a unilateral facet dislocation. Averaged, over all loading directions, lateral mass plates reduced the range of motion to 17% of normal; anterior plates reduced range of motion to 89% of normal. In all loading directions, lateral mass plates performed significantly better than anterior plates (P < 0.05, paired Student t-tests)., Conclusions: Anterior and posterior plating effectively stabilized a reduced unilateral facet dislocation. Lateral mass fixation provided better immobilization than anterior graft and plate.

The authors describe a new technique of internal atlantooccipital screw fixation involving posterior wiring and fusion for the treatment of traumatic atlantooccipital dislocation, which was performed in a 17-year-old male patient involved in a motor vehicle accident and who suffered from atlantooccipital dislocation without neurological injury. At the 6-month follow-up examination, the patient was neurologically intact with a solid occipitocervical fusion and full range of motion of the neck.

Study Design: Biomechanical flexibility tests were performed in specimens receiving anterior lumbar interbody fixation or posterior lumbar interbody fixation using dual threaded cages., Objectives: To determine differences in stability between anterior lumbar interbody fixation and posterior lumbar interbody fixation immediately after surgery and after fatigue., Summary of Background Data: No direct biomechanical comparison of lumbar fixation with threaded anterior lumbar interbody fixation or posterior lumbar interbody fixation cages has been performed previously. METHODS.: Sixteen anterior lumbar interbody fixation specimens and 16 posterior lumbar interbody fixation specimens underwent nondestructive biomechanical testing. Flexibility was assessed during applied flexion, extension, lateral bending, axial rotation, and anteroposterior shear before and after fixation and fatigue. After testing, specimens were dissected, and the quality of fixation was graded., Results: Variability in angular range of motion after fixation was greater than normal interspecimen variability by 89% after anterior lumbar interbody fixation and by 117% after posterior lumbar interbody fixation. During flexion-extension and lateral bending, posterior lumbar interbody fixation allowed a mean of 60% smaller neutral zones than anterior lumbar interbody fixation (P < 0.05, nonpaired Student t test). During axial rotation, anterior lumbar interbody fixation allowed 15% less range of motion than posterior lumbar interbody fixation unless facets were kept intact with posterior lumbar interbody fixation (6 of 16 specimens), in which case anterior lumbar interbody fixation allowed 41% greater range of motion than posterior lumbar interbody fixation. During anteroposterior shear, both anterior lumbar interbody fixation and posterior lumbar interbody fixation restrained range of motion to within 50% of normal. Anterior lumbar interbody fixation loosened, on average, 130% more with fatigue than posterior lumbar interbody fixation during anteroposterior shear., Conclusions: Both anterior lumbar interbody fixation and posterior lumbar interbody fixation provided inconsistent stability. Therefore, stand-alone anterior lumbar interbody fixation or posterior lumbar interbody fixation may often be ineffective clinically. During all modes of loading except axial rotation, posterior lumbar interbody fixation performed slightly better than anterior lumbar interbody fixation, perhaps due to deeper hole preparation and destruction of anterior stabilizers necessary for anterior lumbar interbody fixation. Avoiding resection of facets during posterior lumbar interbody fixation led to significantly better performance during axial rotation.

Objective and Importance: Traumatic spondylolisthesis of the axis may be treated by external immobilization or surgical fixation., Clinical Presentation: We report the case of a 23-year-old man who sustained an Effendi Type II fracture of the axis, for which halo immobilization did not provide adequate stability., Intervention: The unstable fracture was treated by placing lag screws in the pars interarticularis of C2, which reduced the fracture directly but sacrificed no normal spinal motion. The patient developed a solid fusion, and cervical alignment was normal at his 6-month follow-up examination., Conclusion: Although this technique has been reported previously, it is more commonly used in multilevel cervical fusions than for stand-alone repair of C2. Management options, anatomy, and technical considerations for the treatment of traumatic spondylolisthesis are reviewed.