Geometric analysis of pedicle subtraction osteotomy (PSO) for Kyphosis correction: anterior lengthening may occur at the osteotomized body as well as at the discs above and below.

OBJECTIVE: To validate the authors kyphosis correction formula for pedicle subtraction osteotomy (PSO) cases. Additionally, to use the formula to evaluate the safety of PSO by determining if there is anterior lengthening. METHODS: Twenty-two patients with primarily kyphosis corrected by PSO and with clear landmarks on preoperative and postoperative x-rays were selected. Several anatomical lines and angle measurements were utilized as depicted previously in the Vertebral Column Resection formula (see below). Two approximations were calculated: the geometric approximation (G) = (tanG°*2 + 1)*15° and the rough approximation (R) which is about the same amount of actual shortening (x), if parallel length (y) ≥ 40; twice of x, if y < 40. For each patient, the change of segmental kyphosis angle (K°) was measured and compared with G° and R°, and the correlation between each value was analyzed. RESULTS: The absolute Mean ± SE for K - G and K - R was 2.33° ± 0.34 and 6.09° ± 0.58, respectively. K - G is < 3° (p = 0.03). K - R is < 8° (p = 0.001). In other words, K was close to G and R and thus can be predicted by these approximations. Average posterior shortening, anterior shortening, and kyphosis correction at each level were 20.8 ± 2.0 mm, - 3.64 ± 1.5 mm (which equates to anterior lengthening), and 31.05° ± 2.0, respectively. Anterior lengthening occurred in 13 cases (in 4 cases, both at the body as well as at the disc above and below.) The correlation between posterior and anterior shortening was 0.03 (p = 0.88). There were 3 cage insertion cases: 1 had anterior lengthening, while 2 had anterior shortening even with the cage. CONCLUSION: This study validated the geometric and rough approximations originally used in PVCR patients, for PSO patients. Additionally, this study found that anterior lengthening may occur in PSOs usually at the discs, but occasionally at the osteotomized body.

The use of vancomycin powder reduces surgical reoperation in posterior instrumented and noninstrumented spinal surgery.

BACKGROUND: Surgical site infections can complicate posterior spine surgery. Multiple hospital admissions may be required to adequately treat a surgical site infection, which is associated with increased costs and lower patient satisfaction. The objective of this study was to evaluate the efficacy of prophylactic intra-wound vancomycin powder in reducing the incidence of repeat surgery for infections after posterior instrumented and noninstrumented spine surgery. METHODS: A series of consecutive patients who underwent instrumented or noninstrumented posterior spine surgery for any indication by two surgeons from July 2010 to July 2012 were reviewed. The preoperative antibiotic regimens of both surgeons were identical, except that one surgeon applied 1 g vancomycin powder directly to the surgical bed before wound closure, while the other did not. Patient demographics, operative details, and rates of reoperation for wound infection in the control and the treatment groups were compared. RESULTS: Both the control group and treatment group consisted of 150 patients; mean ages were 58.33 and 54.14 years, respectively. Both groups had low rates of deep infection requiring surgical intervention. The treatment group had a significantly lower rate of infection requiring reoperation or surgical debridement (0 %; 95 % CI: 0 %-2.4 %) compared with the control group (4 %; 95 % CI: 1.5 %-8.5 %) (P = 0.0297). The six infections identified in the control group resulted in 12 repeat operative debridement procedures. Gram-positive organisms were identified in 66.7 % of infections. No complications were related to the application of vancomycin powder. CONCLUSIONS: The results of this study demonstrate that adjunctive vancomycin powder applied directly to the surgical bed before closure seems effective in preventing deep infections that require operative debridement following posterior spine surgery.

The effect on the pullout strength by the timing of pedicle screw insertion after calcium phosphate cement injection.

STUDY DESIGN: Biomechanical Cadaveric Study. OBJECTIVE: To characterize the pullout strength of calcium phosphate cement augmented screws between 0 and 6 minutes after cement injection. SUMMARY OF BACKGROUND DATA: Earlier studies with calcium phosphate cement on pedicle screws inserted into a metal mold or sawbone have shown that the augmentation strength can be affected by the time between cement injection and screw insertion. However, these studies only compared soft cement to completely hardened cement with extended waiting times. These extended waiting times are impractical in live spinal surgeries. METHODS: Twenty-four pedicle screws were inserted and pulled out axially from cadaveric bone to make revision models. The 24 screw holes were randomly divided into 4 groups, with each group having 6 holes. For each group, identical pedicle screws were inserted at 0, 2, 4, and 6 minutes after injection with bioresorbable calcium phosphate cement (CPC). After 24 hours, the augmented screws were pulled out axially and their pullout strengths were compared. RESULTS: The difference between secondary pullout strength and primary pullout strength increased up to 4 minutes after cement injection but decreased after 6 minutes but without statistical difference among the 4 time settings (P>0.3). CONCLUSIONS: The augmented screws had similar fixation strength regardless of the time between cement mixture and screw insertion as long as they are inserted within 6 minutes. Augmentation power tends to increase up to 4 minutes after cement injection but decreases after 6 minutes.

Successful management of an anterior thoracic Type IV spinal arteriovenous malformation with two associated aneurysms utilizing vertebrectomy. Technical note.

Anteriorly located Type IV thoracic arteriovenous malformations (AVMs) are difficult to treat surgically. Although high-flow fistula subtypes are amenable to treatment using endovascular techniques, low-flow fistulas should be treated surgically. There are few reports discussing the diagnosis, behavior, and treatment of these spinal fistulas due to their low incidence. Posterior surgical approaches to Type IV spinal AVMs reported in the literature have been associated with high morbidity rates or aborted procedures. The authors report the successful management of a T-12 Type IV spinal AVM with an emphasis on approach, interoperative angiography, and the use of modern instrumentation. To the authors' knowledge, this is also the first reported case of multiple arterial-side aneurysms in a Type IV AVM of the anterior spinal artery.

The Role of Adjustable Scout Lines in Advanced Cervical Spinal Imaging.

STUDY DESIGN/SETTING: Retrospective cohort at a Level 1 trauma center. OBJECTIVE: To compare the anterior-posterior diameter of the cervical central canal using imaging software with both fixed and user-adjustable scout line axial images. SUMMARYOF BACKGROUND DATA: The majority of imaging software programs generate oblique axial images through the lordotic and kyphotic regions of the spine due to a fixed reference line. These oblique axial images are not representative of true canal diameter and often provide inaccurate representation of neural compression. METHODS: Thirty-three consecutive head trauma patients without evidence of pathology in the cervical spine from September 2011 were chosen for the study. The anterior-posterior diameter of the cervical (levels C2-T1) central canal was measured on axial slices using the default non-adjustable ("fixed") reference line on the picture archiving and communication viewer by three observers and then re-measured using an adjustable scout line on the midline sagittal that most bisected the endplates in a parallel fashion. The two measurements from the three independent observers were then compared directly for differences in the AP canal diameter at each level. RESULTS: The average difference between the measurements of the central canal using the fixed scout line versus the adjustable scout line ranged from -1.34±1.59 mm at the C2-C3 level to 1.78±2.32 mm at the C7-T1 level. Standard axial images of the cervical spine underestimated the canal space in the upper cervical spine and overestimated the space in the lower cervical spine. The measurement values using the fixed scout line versus the adjustable scout line did not correlate as indicated by low to moderate Pearson r and ICC values. CONCLUSIONS: There are clear differences between axial slices generated with adjusted and fixed scout lines particularly at disc levels that are not orthogonal to the screen edges.

Can Intraoperative Spinal Cord Monitoring Reliably Help Prevent Paraplegia During Posterior Vertebral Column Resection Surgery?

STUDY DESIGN: Retrospective case series. OBJECTIVE: Analyze patients who underwent posterior vertebral column resection (PVCR) above the conus medullaris with intraoperative spinal cord monitoring (SCM) data loss. SUMMARY OF BACKGROUND DATA: PVCR is a powerful technique for treating severe spinal deformity but carries a high risk for major spinal cord deficits. METHODS: We assessed clinical, radiographic, and electrophysiologic monitoring and operative records of 90 consecutive adult and pediatric patients (mean age, 24.8 years; range, 7.5-76.8) who underwent PVCR above the conus medullaris for severe spinal deformity performed from 2002 to 2010 by one surgeon at one institution. RESULTS: Fifteen of 90 patients (16.7%) (10 male/5 female; mean age, 15 years) lost SCM (n = 13) or had data degradation meeting warning criteria (n = 2). Diagnoses were kyphoscoliosis (n = 8), angular kyphosis (n = 3), global kyphosis (n = 2), and severe scoliosis (n = 2). Seven were revisions. The average pre-/postoperative scolioses were 99° (range, 32°-152°) and 43° (range, 6°-76°), respectively. The average pre-/postoperative kyphoses were +100° (range, 60°-170°) and +54° (range, 28°-100°), respectively. SCM fluctuated during osteotomy on nine occasions, stabilizing with elevation of blood pressure in addition to anterior spinal cord decompression in four, correction of subluxation in one, and traction reduction in one. Seven patients had SCM changes during rod compression. Three required partial release of correction, two larger cage insertion, one subluxation correction, and one pedicle screw removal. One experienced changes during rod placement/removal, and another, as a result of hypothermia. Data returned in all after prompt intervention (mean, 10.1 minutes; range, 1-60) and all awoke with intact lower extremity function. CONCLUSION: The prevalence of SCM changes during PVCR above the conus medullaris was 16.7%, mostly during osteotomy and rod/screw compression. Data returned with prompt intervention and all had intact lower extremity motor function postoperatively. These SCM "saves" strongly emphasize the importance of multimodality neurophysiologic monitoring during high-risk cases, minimizing postoperative complications.

Progressive Myelopathy Patients Who Lack Spinal Cord Monitoring Data Have the Highest Rate of Spinal Cord Deficits Following Posterior Vertebral Column Resection Surgery.

OBJECTIVES: The authors analyzed patients who underwent posterior vertebral column resection (PVCR). All patients had spinal cord monitoring (SCM) attempted but some did not have predictable and usable tracings. SUMMARY OF BACKGROUND DATA: Posterior vertebral column resection is a powerful technique to correct severe spinal deformities but it has the potential for major neurologic complications. Spinal cord monitoring is extremely helpful in managing these difficult patients. METHODS: Spinal cord monitoring data, operative reports, charts, and radiographs of 112 consecutive adult and pediatric patients (mean age, 23.5 years; range, 5.8-74.0 years) who underwent PVCR were reviewed. All surgical procedures were performed between 2002 and 2010 by 1 surgeon at a single institution. RESULTS: Twenty patients (11 male, 9 female; mean age, 15.9 years) of 112 (17.9%) did not have detectable SCM tracings during surgery. Average preoperative and postoperative scoliosis for these 20 patients was 79.2° and 41.3°, respectively. Average preoperative and postoperative kyphosis was 106.6° and 59.8°, respectively. Thirteen of the 20 were revisions. Preoperative neurologic status included acute progressive myelopathy (n = 9), no lower extremity function (n = 6), chronic weak lower extremities (n = 2), chronic quadriparesis (n = 1), and normal (n = 2). Four of 9 patients with acute progressive myelopathy developed transient paraplegia postoperatively. They had angular kyphosis (mean, 116.3°) and 3 were revisions. Compared with the 92 patients who had obtainable intraoperative SCM and no spinal cord deficits, the risk of developing postoperative paraplegia in patients who had no SCM tracings was statistically higher (p = .0008). All 4 with spinal cord deficits after surgery regained varying degrees of lower extremity function and resumed ambulatory status at most recent follow-up. CONCLUSIONS: The prevalence of unobtainable intraoperative SCM during PVCR was 17.9% (20 of 112). Postoperative transient paraplegia occurred exclusively in patients with no monitorable data as a result of angular kyphosis with acute progressive myelopathy. The rate of transient spinal cord deficits was significantly higher when there was no obtainable SCM (4 of 20 vs. 0 of 92 with SCM; p = .0008).

Cost savings analysis of intrawound vancomycin powder in posterior spinal surgery.

BACKGROUND CONTEXT: Recent studies have shown that prophylactic use of intrawound vancomycin in posterior instrumented spine surgery substantially decreases the incidence of wound infections requiring repeat surgery. Significant cost savings are thought to be associated with the use of vancomycin in this setting. PURPOSE: To elucidate cost savings associated with the use of intrawound vancomycin in posterior spinal surgeries using a budget-impact model. STUDY DESIGN: Retrospective cohort study. PATIENT SAMPLE: Data from a cohort of 303 patients who underwent spinal surgery (instrumented and noninstrumented) over 2 years were analyzed; 96 of these patients received prophylactic intrawound vancomycin powder in addition to normal intravenous (IV) antibiotic prophylaxis, and 207 received just routine IV antibiotic prophylaxis. Patients requiring repeat surgical procedures for infection were identified, and the costs of these additional procedures were elucidated. OUTCOME MEASURE: Cost associated with the additional procedure to remediate infection in the absence of vancomycin prophylaxis. METHODS: We retrospectively reviewed the cost of return procedures for treatment of surgical site infection (SSI). The total reimbursement received by the health care facility was used to model the costs associated with repeat surgery, and this cost was compared with the cost of a single local application of vancomycin costing about $12. RESULTS: Of the 96 patients in the treatment group, the return-to-surgery rate for SSI was 0. In the group without vancomycin, seven patients required a total of 14 procedures. The mean cost per episode of surgery, based on the reimbursement, the health care facility received was $40,992 (range, $14,459-$114,763). A total of $573,897 was spent on 3% of the 207-patient cohort that did not receive intrawound vancomycin, whereas a total of $1,152 ($12×96 patients) was spent on the cohort treated with vancomycin. CONCLUSIONS: This study shows a reduction in SSIs requiring a return-to-surgery-with large cost savings-with use of intrawound vancomycin powder. In our study population, the cost savings totaled more than half a million dollars.

The prevalence of abnormal preoperative neurological examination in Scheuermann kyphosis: correlation with X-ray, magnetic resonance imaging, and surgical outcome.

STUDY DESIGN: Retrospective. OBJECTIVE: The purpose of this study was to report the prevalence of abnormal neurological findings detected by physical examination in Scheuermann kyphosis and to correlate it to radiographs, magnetic resonance imaging (MRI) findings, and results of operative treatment. SUMMARY OF BACKGROUND DATA: There have been sporadic reports about abnormal neurological findings in patients with Scheuermann kyphosis. METHODS: Among 82 patients with Scheuermann kyphosis who underwent corrective surgery, 69 primary cases were selected. Patients' charts were reviewed retrospectively in terms of pre and postoperative neurological examinations. Sensory or motor change was defined as an abnormal neurological examination. Their duration, associated problems, and various parameters on preoperative radiographs and MRI examinations were also measured to search for any atypical findings associated with an abnormal neurological examination. RESULTS: There were 6 cases (9%) (group AbN), with an abnormal neurological examination ranging from severe myelopathy to a subtle change (e.g., sensory paresthesias on trunk). Five patients recovered to a normal neurological examination after corrective surgery. The remaining 1 patient with severe myelopathy also showed marked improvement and was ambulatory unassisted by 2-year follow-up. In patients with a normal neurological examination (group N, n = 63), only 1 patient had neurological sequelae because of anterior spinal artery syndrome after combined anterior-posterior correction. No preoperative radiographical parameters were significantly different between groups. Average age was 21.3 (AbN) and 18.6 (N) years (P = 0.55). Average preoperative T5-12 kyphosis was 69.0° (AbN) and 72.5° (N) (P = 0.61). Forty-two magnetic resonance images were obtained and all showed typical findings of Scheuermann kyphosis. Five patients in the AbN group (1 patient underwent computed tomography/myelography) and 37 patients in the N group underwent an MRI. CONCLUSION: The prevalence of abnormal neurological findings in Scheuermann kyphosis was 9%, emphasizing the importance of performing a detailed preoperative neurological examination. If congenital stenosis or a herniated thoracic disc is present, myelopathy can occur. No radiographical findings correlated with the abnormal preoperative neurological examinations. A normal MRI can exist in the face of an abnormal neurological examination, and conversely, a normal neurological examination can be seen with an abnormal MRI. Surgery was successful in alleviating abnormal neurological issues. LEVEL OF EVIDENCE: 4.

Matched Cohort Analysis of Posterior-Only Vertebral Column Resection Versus Combined Anterior/Posterior Vertebrectomy for Severe Spinal Deformity.

STUDY DESIGN: Retrospective matched cohort analysis. SUMMARY OF BACKGROUND DATA: Posterior-only vertebral column resection (P-VCR) is a potential alternative to combined anterior/posterior vertebrectomy (A-P/VCR) for the treatment of severe spinal deformity. OBJECTIVE: To examine a matched cohort of adult and pediatric patients with severe spinal deformity treated with A/P-VCR versus P-VCR. METHODS: Databases of 2 spine surgeons at 1 institution from 1994 to 2007 were reviewed. Patients were matched based on age at surgery (within 10 years), diagnosis, curve pattern, vertebrae resected (within 1), levels of vertebrae resected (within 2), levels fused (within 5), and minimum 2-year follow-up. A total of 34 P-VCR patients were identified who appropriately matched 34 A/P-VCR patients. The etiology of the deformity and type of curve were matched directly so that they were identical for each matched pair. The remainder of the inclusion parameters was matched as closely as possible between the 2 groups according to the criteria listed above. RESULTS: Final coronal Cobb correction P-VCR versus A/P-VCR showed that 52.6% versus 53.9% (p = .8) was similar, whereas P-VCR final sagittal Cobb correction was superior: 53.0% versus 40.0% (p = .017). The P-VCR group had a significantly shorter total operative time (p = .002) and total length of stay (p = .003). Complications rates were similar and relatively infrequent for both P-VCR and A/P-VCR, including wound infections requiring operative intervention, subsequent revision surgery, and transient motor deficits. Total Scoliosis Research Society scores improved from preoperative to final follow-up for both P-VCR (p = .007) and A/P-VCR (p = .07) groups. CONCLUSIONS: Posterior-only vertebral column resection is a challenging yet safe and effective means of treating severe scoliosis and/or kyphosis. Compared with an A/P-VCR for severe spinal deformity, P-VCR demonstrated shorter operative time and hospital stay, as well as improved sagittal correction and Scoliosis Research Society scores.

Transforaminal versus anterior lumbar interbody fusion in long deformity constructs: a matched cohort analysis.

STUDY DESIGN: Prospectively enrolled, retrospectively analyzed matched cohort analysis. OBJECTIVE: Evaluate the relative merits of transforaminal lumbar interbody fusion (TLIF) and anterior lumbar interbody fusion (ALIF) when performed in long deformity constructs. SUMMARY OF BACKGROUND DATA: Interbody fusion is frequently used at the caudal levels of long-segment spinal deformity instrumentation constructs to protect the sacral implants and enhance fusion rates. However, there is a paucity of literature regarding which technique is more efficacious. METHODS: Forty-two patients who underwent TLIF and 42 patients who underwent ALIF were matched with respect to age, sex, comorbidities, curve magnitude, fusion length, and ALIF/TLIF level. Radiographs and clinical outcomes were compared at minimum 2-year follow-up. RESULTS: Age averaged 54.0 years and instrumented vertebrae averaged 13.6. TLIFs had less operative time (481 vs. 595 min, P = 0.0007), but greater blood loss (2011 vs. 1281 mL, P = 0.0002). Overall complications (TLIF, 12/42 vs. ALIF, 15/42) and neurological complications (TLIF, 4/42 vs. ALIF, 3/42) did not differ. One pseudarthrosis occurred at an ALIF level, with none at TLIF levels. Patients who underwent ALIF began with lower SRS scores but showed more improvement (44.4 to 70.7 vs. 58.6 to 70.6, P = 0.0043). ODI scores in both groups improved similarly. Regionally, ALIFs engendered more lordosis than TLIFs at L3-S1 (gain of 6.9° vs. -2.6°, P < 0.0001) but not T12-S1 (gain of 11.5° vs. 7.9°, P = 0.29). Locally, ALIFs created more lordosis at L4-L5 (gain of 5.6° vs. -1.7°, P < 0.0001) and L5-S1 (gain of 2.5° vs. -1.4°, P = 0.022), but not at L3-L4 (gain of 5.3° vs. 4.0°, P = 0.65). Patients who underwent TLIF obtained greater correction of anteroposterior Cobb angles in lumbar (reduction of 22.4° vs. 9.9°, P < 0.0001) and lumbosacral curves (reduction of 10.3° vs. 3.4°, P < 0.0001). CONCLUSION: Spinal deformity surgery used TLIFs rather than ALIFs resulted in shorter operative time with no difference in complication rates. ALIFs provided more segmental lordosis, whereas TLIFs afforded better correction of scoliotic curves.

Proximal junctional kyphosis in primary adult deformity surgery: evaluation of 20 degrees as a critical angle.

BACKGROUND: : Multiple studies have reported on the prevalence of proximal junctional kyphosis (PJK) following spinal deformity surgery; however, none have demonstrated its significance with respect to functional outcome scores or revision surgery. OBJECTIVE: : To evaluate if 20° is a possible critical PJK angle in primary adult scoliosis surgery patients as a threshold for worse patient-reported outcomes. METHODS: : Clinical and radiographic data of 90 consecutive primary surgical patients at a single institution (2002-2007) with adult idiopathic/degenerative scoliosis and 2-year minimum follow-up were analyzed. Assessment included radiographic measurements, but most notably sagittal Cobb angle of the proximal junctional angle at preoperation, between 1 and 2 months, 2 years, and ultimate follow-up. RESULTS: : Prevalence of PJK ≥20° at 3.5 years was 27.8% (n = 25). Those with PJK ≥20° at ultimate follow-up were older (mean 56 vs 46 years), had lower number of levels fused (median 8 vs 11), and were proximally fused to the lower thoracic spine more often than upper thoracic spine (all P < .001). PJK ≥20° was associated with significantly higher body mass index and fusion to the sacrum with iliac screws (P < .016, P < .029, respectively). Scoliosis Research Society outcome score changes were lower for PJK patients, but not significantly different from those in the non-PJK group. CONCLUSION: : PJK ≥20° in primary adult idiopathic/degenerative scoliosis does not lead to revision surgery for PJK, but is univariately associated with older age, shorter constructs starting in the lower thoracic spine, obesity, and fusion to the sacrum. The negative results, supported by Scoliosis Research Society outcome data, provide important guidance on the postoperative management of such PJK patients. ABBREVIATIONS: : BMI, body mass indexLIV, lowest instrumented vertebraeODI, Oswestry Disability IndexPJ, proximal junctionalPJK, proximal junctional kyphosisSRS, Scoliosis Research SocietyUIV, upper instrumented vertebra.

Methods to decrease postoperative infections following posterior cervical spine surgery.

BACKGROUND: To decrease surgical site infections, we initiated a protocol of preliminary preparation of the skin and surrounding plastic drapes with alcohol foam, and the placement of a suprafascial drain in addition to a subfascial drain in obese patients in 2004. In 2008, we additionally placed 500 mg of vancomycin powder into the wound prior to closure. The purpose of this study was to analyze the infection rates for three groups: Group C (control that received standard perioperative intravenous antibiotics alone), Group AD (alcohol foam and drain), and Group VAD (vancomycin with alcohol foam and drain). METHODS: A consecutive series of 1001 all-posterior cervical spine surgical procedures performed at one institution by the senior author from 1995 to 2010 was retrospectively reviewed. These surgical procedures included foraminotomy, laminectomy, laminoplasty, arthrodesis, instrumentation, and/or osteotomies. There were 483 patients in Group C, 323 in Group AD, and 195 in Group VAD. RESULTS: In Group C, nine (1.86%) of the 483 patients had an acute postoperative deep infection, in which methicillin-resistant Staphylococcus aureus was the most common pathogen. A significantly higher rate of infection was found in patients with an active smoking history (p = 0.008; odds ratio = 2.6 [95% confidence interval, 1.0 to 7.1]), rheumatoid arthritis (p = 0.005; odds ratio = 4.0 [95% confidence interval, 1.4 to 7.9]), and a body mass index of ≥30 kg/m2 (p = 0.005; odds ratio = 4.1 [95% confidence interval, 1.5 to 7.7]). Group AD (n = 323) had one infection, a significant decrease compared with Group C (p = 0.047). In Group VAD, none of the 195 patients had infections, which was also a significant decrease compared with Group C (p = 0.048). CONCLUSIONS: In this study, preliminary preparation with alcohol foam and the placement of suprafascial drains for deep wounds resulted in one postoperative deep infection in 323 surgical procedures. The addition of intrawound vancomycin powder in 195 consecutive posterior cervical spine surgical procedures resulted in no infections and no adverse effects. To our knowledge, this is the first description of a technique for significantly decreasing postoperative cervical spine infections.

C2 nerve root sectioning in posterior atlantoaxial instrumented fusions: a structured review of literature.

OBJECTIVE: To review published series describing C1-2 posterolateral instrumentation, comparing outcomes in patients who had and did not have C2 nerve sacrifice. METHODS: Online databases were searched for English-language articles between 1994 and April 2011 pertaining to posterior atlantoaxial instrumentation with C1 lateral mass and C2 screws. Twenty studies describing 732 patients with C2 nerve preservation and 6 studies describing 361 patients with C2 sacrifice met inclusion criteria. RESULTS: All but one small study without a control group were retrospective case series, making all evidence class III. Excluding C2 nerve dysfunction, no neurological deterioration was observed. Three instances of vertebral artery injury were secondary to soft tissue dissection and one was secondary to C1 screw insertion. There were seven instances of C1 screw malposition in the preservation group and none in the section group. Reported in roughly 20% of patients, mean estimated blood loss tended to be lower with C2 nerve sectioning (213 vs. 471 mL) and operative times were somewhat shorter (118 vs. 132 minutes). C2 nerve section resulted in greater symptomatic numbness (11.6% vs. 1.3%; P < 0.0001) but less neuropathic pain (0.3% vs. 4.7%; P = 0.0002) compared with C2 preservation. CONCLUSIONS: Sacrifice of the C2 nerve root to aid in the insertion of C1 lateral mass screws when performing posterior atlantoaxial instrumented fusions is a treatment option (class III). It may decrease blood loss and operative duration, potentially advantageous in elderly or frail patients. Numbness occurred in roughly 12% of patients, an outcome that may be unacceptable to certain patient populations, but neuropathic pain was nearly absent in reported studies with nerve section. C2 nerve preservation and retraction for C1 screw placement may have higher incidence of neuropathic pain (~5%). Rates of fusion are universally high independent of C2 nerve technique.

C2 nerve root sectioning in posterior C1-2 instrumented fusions.

OBJECTIVE: To analyze qualitatively C2 nerve dysfunction after its transection in C1-2 posterolateral instrumented fusions. METHODS: From 2002-2010, 20 consecutive patients underwent posterolateral instrumented fusions using C1 lateral mass and C2 pars or pedicle screws, mainly for type 2 dens fractures. Screws were placed under lateral fluoroscopic guidance using standard techniques. Bilateral C2 nerve roots were coagulated and transected in all patients. Mean follow-up was 30.7 months and consisted of clinical and radiographic examinations, telephone interviews, and mailed visual analogue scale (VAS) questionnaires assessing C2 nerve dysfunction. RESULTS: One patient was lost to follow-up after the initial postoperative visit. Fusion was evident in all patients with 12 months of follow-up and two of three patients with <12 months of follow-up. There were no instances of unintended neurologic deficits, vascular injury, cerebrospinal fluid (CSF) leak, or hardware malfunction or malposition. By the 2-week or 6-week office visit, 4 of 20 patients complained of sensory disturbance, and 2 had paresthesias in the C2 distribution. After longer follow-up, one additional patient developed mild sensory symptoms. Quality of life was adversely affected in only one patient. No patient developed neuropathic pain at any time after C2 sectioning. CONCLUSIONS: This study is the first series to describe C2 nerve function after posterior atlantoaxial instrumented fusion in adults of all ages. Sacrifice of the C2 nerve root increases fusion surface, allows for better preparation and decortication of the atlantoaxial joint, improves visualization for screw placement, and decreases blood loss and operative time without major clinical consequences.

Comparative analysis of clinical outcome and complications in primary versus revision adult scoliosis surgery.

STUDY DESIGN: A retrospective case comparison study. OBJECTIVE: We compared clinical outcome and complications in adult patients who underwent primary (P) versus revision (R) scoliosis surgery. SUMMARY OF BACKGROUND DATA: There is a paucity of data comparing P versus R adult scoliosis patients with respect to their complication rates and clinical outcome. METHODS: Assessment of 250 consecutive adult patients who underwent P versus R surgery for idiopathic or de novo scoliosis between 2002 and 2007, with a minimum 2-year follow-up, was performed. RESULTS: There were 126 patients in the P group and 124 in the R group. Mean age at surgery (P = 51.2 vs. R = 51.6 years, P = 0.79), length of follow-up (P = 3.6 vs. R = 3.6 years, P = 0.94), comorbidities (P = 0.43), and smoking status (P = 0.98) were similar between the 2 groups. Body mass index (P = 25.5 vs. R = 27.4 kg/m, P = 0.01), number of final instrumented levels (P = 10.5 vs. R 12.1 levels, P = 0.00), fusion to the sacrum (P = 61.0% vs. R = 87.1%, P = 0.00), osteotomy (P = 14.3% vs. R = 54.9%, P = 0.00), length of surgery (P = 6.5 vs. R = 8.2 hours, P = 0.00), and estimated blood loss (P = 1072.1 vs. R = 1401.3 mL, P = 0.05) were different. Primary patients had significantly lower overall complications than revision patients (P = 45.2% vs. R = 58.2%, P = 0.042). Primary patients reported significantly higher preoperative and final clinical outcome measures in function, pain, and subscore SRS domains and ODI compared with revision patients (all P < 0.05). Patients older than 60 years of age, however, reported similar SRS and ODI scores between the 2 groups. The extent of surgical benefit patients received, that is, final minus preoperative score, was similar in all categories between the 2 groups. CONCLUSION: Adult patients undergoing primary scoliosis surgery had significantly lower overall complications compared with revision patients. Primary patients reported higher preoperative and final clinical outcome measures than revision patients, although this difference disappeared in older patients. The benefit of surgery was similar between the 2 groups.

Major complications in revision adult deformity surgery: risk factors and clinical outcomes with 2- to 7-year follow-up.

STUDY DESIGN: Retrospective cohort comparative study. OBJECTIVE: To determine the prevalence of major complications, identify risk factors, and assess long-term clinical benefit after revision adult spinal deformity surgery. SUMMARY OF BACKGROUND DATA: No study has analyzed risk factors for major complications in long revision fusion surgery and whether or not occurrence of a major complication affects ultimate clinical outcome. METHODS: Analysis of consecutive adult patients who underwent multilevel revision surgery for spinal deformity with a minimum 2-year follow-up was performed. All complications were classified as either major or minor. Outcome analysis was conducted with the Scoliosis Research Society and Oswestry Disability Index scores. RESULTS: A total of 166 patients (mean age = 53.8 years) were identified with a mean follow-up of 3.5 years (range: 2-7). Primary diagnoses included idiopathic/de novo scoliosis (107), degenerative (35), trauma (7), neuromuscular scoliosis (6), congenital deformity (5), ankylosing spondylitis (2), tumor (2), Scheuermann kyphosis (1), and rheumatoid arthritis (1). Most common secondary diagnoses that necessitated revision surgery were adjacent segment disease, fixed sagittal imbalance, and pseudarthrosis. Overall, 34.3% of patients developed major complications (19.3% perioperative; 18.7% follow-up). Associated risk factors for perioperative complications were patient- (age > 60 years, medical comorbidities, obesity) and surgery-related (pedicle subtraction osteotomy). Performance of a 3-column osteotomy and postoperative radiographic changes that suggested progressive loss of sagittal correction were recognized as risk factors for follow-up complications. Equivalent outcome scores were reported by patients preoperatively, but those experiencing follow-up complications reported lower scores at the final follow-up. CONCLUSION: Overall, 34.4% of patients experienced major complications after long revision fusion surgery. Different risk factors were identified for perioperative versus follow-up complications. The occurrence of a follow-up, not but perioperative, major complication seemed to have a negative impact on ultimate clinical outcome.

Hemostatic techniques reduce hospital stay following multilevel posterior cervical spine surgery.

BACKGROUND: Despite meticulous hemostasis, persistent postoperative drain output following posterior cervical spine procedures often necessitates a prolonged length of hospital stay. We sought to determine if thrombin-soaked absorbable gelatin compressed sponge can decrease postoperative drain output and the length of hospital stay after multilevel posterior cervical spine surgery. METHODS: We performed a retrospective analysis of forty-three pairs of patients who had undergone either posterior cervical decompression and/or fusion of three or more levels by the same surgeon. The patients were matched according to intraoperative blood loss, age, sex, and number of involved levels. Control patients were managed between 2004 and 2007, whereas study patients were managed between 2008 and 2011. The only variable between the study and control groups was that, in the study group, absorbable gelatin compressed sponge was soaked in thrombin and applied over the exposed spine before wound closure. A subfascial drain was used in all patients. Total drain output, time for the drainage to decrease to <30 mL per eight-hour shift (at which point the drain was discontinued), the length of stay, the number of readmissions, and postoperative complications were analyzed. RESULTS: Total drain output averaged 93 mL in the study group and 204 mL in the control group (p < 0.0001). The average time for the drainage to decrease to <30 mL per eight-hour shift was 2.5 shifts in the study group and 4.4 shifts in the control group (p < 0.0001). Length of stay averaged 1.3 days (cumulative total, fifty-seven days) in the study group and 2.2 days (cumulative total, ninety-five days) in the control group (p < 0.0001). Persistent drain output was the primary reason preventing discharge on the first postoperative day. There were no infections, epidural hematomas, or readmissions within thirty days of discharge in either group. No patient developed adverse reactions attributable to the thrombin-soaked absorbable gelatin compressed sponge. CONCLUSIONS: Application of thrombin-soaked absorbable gelatin compressed sponge at the end of multilevel posterior cervical spinal surgery significantly decreased postoperative drain output and consequent hospital stay. LEVEL OF EVIDENCE: Therapeutic Level III.

Comparison of spinal deformity surgery in patients with non-insulin-dependent diabetes mellitus (NIDDM) versus controls.

STUDY DESIGN: A retrospective review. OBJECTIVE: To quantify the exact impact of non-insulin-dependent diabetes mellitus (NIDDM) on operative complications and additional surgeries associated with spinal deformity surgery. SUMMARY OF BACKGROUND DATA: There are many references supporting diabetes mellitus (DM) as one of the major risk factors for perioperative complications in spinal surgery. However, the results vary depending on the type of DM, suggesting that insulin-dependent DM causes more complications than NIDDM, which is far more prevalent in the adult population with spinal deformity. METHODS: Among 5119 adult patients (older than 40 yr) with deformities, 23 patients with NIDDM and 23 control (group C) patients with a minimum 2-year follow-up were selected. Both groups were matched for age at surgery, sex, body mass index, number of comorbidities, smoking history, current and prior fusion levels, estimated blood loss, and the amount of transfusion. Pre- and final Scoliosis Research Society (SRS) scores and Oswestry Disability Index (ODI), number of perioperative complications, and additional surgeries were compared. Within the group with NIDDM, patients with (+) or without (-) complications were compared in terms of postoperative glucose control. RESULTS: There were no significant differences in the number of major or minor complications or additional surgeries between the 2 groups. There was no significant difference in postoperative glucose control with the NIDDM group (+) and (-). Group C reported significantly improved scores at final follow-up in all SRS domains and ODI. The group with NIDDM reported improvement in all domains except for the mental health and pain domains. However, there were no significant differences between the group with NIDDM and group C in terms of SRS and ODI scores preoperatively and postoperatively. CONCLUSION: Contrary to traditional thinking, properly selected NIDDM was not a significant risk factor for perioperative complications or additional surgeries in adult patients with spinal deformities.

Função cognitiva no tratamento cirúrgico de pacientes com aneurismas intracranianos não-rotos: revisão sistemática da literatura / Cognitive function in neurosurgical clipping of patients with unruptured aneurysms: a systematic

Existe um consenso na literatura de que a maioria dos aneurismas intracranianos não-rotos pode ser tratada com índices aceitáveis de morbid-mortalidade. No entanto, alguns estuduosos recentemente reportaram danos cognitivos no período pós-operatório, sugerindo que poderiam ser atribuídos à clipagem neurucirúrgica. Os objetivos deste estudo revisar e discutir aspectos referentes à função cognitiva a ao tratamento neurocirúrgico em pacientes com aneurisma intracranianos não-roto.