Stephen J. Lewis

Early versus Delayed Decompression for Traumatic Cervical Spinal Cord Injury: Results of the Surgical Timing in Acute Spinal Cord Injury Study (STASCIS)

Background There is convincing preclinical evidence that early decompression in the setting of spinal cord injury (SCI) improves neurologic outcomes. However, the effect of early surgical decompression in patients with acute SCI remains uncertain. Our objective was to evaluate the relative effectiveness of early (<24 hours after injury) versus late (≥24 hours after injury) decompressive surgery after traumatic cervical SCI. Methods We performed a multicenter, international, prospective cohort study (Surgical Timing in Acute Spinal Cord Injury Study: STASCIS) in adults aged 16–80 with cervical SCI. Enrolment occurred between 2002 and 2009 at 6 North American centers. The primary outcome was ordinal change in ASIA Impairment Scale (AIS) grade at 6 months follow-up. Secondary outcomes included assessments of complications rates and mortality. Findings A total of 313 patients with acute cervical SCI were enrolled. Of these, 182 underwent early surgery, at a mean of 14.2(±5.4) hours, with the remaining 131 having late surgery, at a mean of 48.3(±29.3) hours. Of the 222 patients with follow-up available at 6 months post injury, 19.8% of patients undergoing early surgery showed a ≥2 grade improvement in AIS compared to 8.8% in the late decompression group (OR = 2.57, 95% CI:1.11,5.97). In the multivariate analysis, adjusted for preoperative neurological status and steroid administration, the odds of at least a 2 grade AIS improvement were 2.8 times higher amongst those who underwent early surgery as compared to those who underwent late surgery (OR = 2.83, 95% CI:1.10,7.28). During the 30 day post injury period, there was 1 mortality in both of the surgical groups. Complications occurred in 24.2% of early surgery patients and 30.5% of late surgery patients (p = 0.21). Conclusion Decompression prior to 24 hours after SCI can be performed safely and is associated with improved neurologic outcome, defined as at least a 2 grade AIS improvement at 6 months follow-up.

Pedicle subtraction osteotomy for the treatment of fixed sagittal imbalance

Background: Fixed sagittal imbalance (a syndrome in which the patient is only able to stand with the weight-bearing line in front of the sacrum) has many etiologies. The most commonly reported technique for correction is the Smith-Petersen osteotomy. Few reports on pedicle subtraction procedures (resection of the posterior elements, pedicles, and vertebral body through a posterior approach) are available in the peer-reviewed literature. We are aware of no report involving a substantial number of patients with coexistent scoliosis who underwent pedicle/vertebral body subtraction for the treatment of fixed sagittal imbalance. Methods: Twenty-seven consecutive patients in whom sagittal imbalance was treated with lumbar pedicle subtraction osteotomy at one institution were analyzed. Radiographic analysis included assessment of thoracic kyphosis, lumbar lordosis, lordosis through the pedicle subtraction osteotomy site, and the C7 sagittal plumb line. Outcomes analysis was performed with use of a before-and-after pain scale, items from the Oswestry questionnaire, and the Scoliosis Research Society (SRS) questionnaire after a minimum duration of follow-up of two years. Complications and radiographic findings were also analyzed for the entire group. Results: Overall, the average increase in lordosis was 34.1° and the average improvement in the sagittal plumb line was 13.5 cm. One patient had development of a lumbar pseudarthrosis through the area of pedicle subtraction osteotomy, and six patients had development of a thoracic pseudarthrosis. Two patients had development of increased kyphosis at L5/S1, caudad to the fusion, resulting in some loss of sagittal correction. There were significant improvements in the overall Oswestry score (p < 0.0001) and the pain-scale score (p = 0.0002). Most patients reported improvement in terms of pain and self-image as well as overall satisfaction with the procedure. Conclusions: Pedicle subtraction osteotomy is a useful procedure for patients with fixed sagittal imbalance. A worse clinical result is associated with increasing patient comorbidities, pseudarthrosis in the thoracic spine, and subsequent breakdown caudad to the fusion. Level of Evidence: Therapeutic study, Level IV (case series [no, or historical, control group]). See Instructions to Authors for a complete description of levels of evidence.

Complications and Outcomes of Pedicle Subtraction Osteotomies for Fixed Sagittal Imbalance

Study Design. Radiographic analysis, outcomes analysis (pain scale, Oswestry, SRS-24), and accumulation of complications. Outcomes and complications collected prospectively. Radiographic analysis performed retrospectively. Objectives. To assess the benefits and stress complications of pedicle subtractions osteotomies for patients with fixed sagittal imbalance. Summary of Background Data. Few reports on pedicle subtraction osteotomies exist in the peer-review literature for conditions other than trauma and ankylosing spondylitis. Materials and Methods. Thirty-three consecutive patients with sagittal imbalance treated with lumbar pedicle subtraction osteotomy at one institution (minimum 2-year follow-up) were analyzed. Complications were also analyzed for the entire group of consecutive pedicle subtraction osteotomies done at our institution to date (n = 66). Results. For the 33 patients with minimum 2-year follow-up, there were significant improvements in the overall Oswestry score (P 0.0001) and pain score (P = 0.0001). Most patients reported improvement in pain and self-image and reported overall satisfaction based on ultimate SRS-24 questionnaire. There was one pseudarthrosis in the lumbar spine through an area of pedicle subtraction osteotomy (area of previous laminectomy and nonunion), and six patients had thoracic pseudarthroses (levels other than the osteotomy level) and one patient had a pseudarthrosis at L5-S1. Two patients had acute angular kyphosis at the thoracolumbar junction at the proximal end of the construct. Five patients who experienced transient neurologic deficits resolved their deficits after central canal enlargement. Conclusions. The clinical result with pedicle subtraction osteotomy is reduced with pseudarthrosis in the thoracic or lumbar spine and subsequent breakdown adjacent to the fusion. For patients with a degenerative sagittal imbalance etiology the results were worse and the complications were higher. Central canal enlargement is critical.

Minimum 2-year analysis of sacropelvic fixation and L5-S1 fusion using S1 and iliac screws.

Study Design. An analysis of lumbosacral fusions for high-grade spondylolisthesis fusions with reduction and long fusions to the sacrum in ambulatory adults. Objective. To assess the clinical and radiographic results of lumbosacral fusions using bilateral S1 and iliac screws. Summary of Background Data. S1 screws often fail with lumbosacral fusions, whereas L5–S1 pseudarthrosis is common in patients with deformity. Materials and Methods. A total of 81 patients (38 revision, 43 primary) with minimum 2-year follow-up (average, 4.2 years; range, 2.0–7.1 years) underwent L5–S1 fusion using S1 and iliac screws (158 screws). Forty-nine of 81 constructs (61%) included an anterior load-sharing/fixation device. Group 1 included isthmic spondylolisthesis (n = 42), whereas Group 2 included long fusions (≥3 levels) to the sacrum (n = 39). In Group 2, 15 patients (Group 2A) were fused from L1, L2, or L3 to the sacrum (3–5 levels, average 3.3 levels) and 24 patients (Group 2B) were fused from the thoracic spine to the sacrum (6–17 levels, average 11.5 levels). Twelve patients had pseudarthrosis at L5–S1. A patient questionnaire was completed. Results. A total of 36 of the 38 revision patients had previous iliac crest harvesting, yet iliac screws were placed in 34 of 36 patients. Overall, 78 of 80 patients had iliac crest harvesting (one not attempted). None had loss of screw fixation or iliac crest fracture after harvesting. Four of the 81 patients (4.9%) had pseudarthrosis at L5–S1 after reconstruction. This included solid fusion in 10 of 12 patients presenting with L5–S1 pseudarthrosis. Fourteen percent of patients experienced some discomfort over the iliac screws; however, only one patient required screw removal. Conclusions. Bilateral iliac screws coupled with bilateral S1 screws provide excellent distal fixation for lumbosacral fusions with a high fusion rate (95.1%) in high-grade spondylolisthesis and long fusions to the sacrum. Previous iliac crest harvesting does not prevent ipsilateral screw placement (34 of 36 patients) or additional iliac harvesting (78 of 80 patients).

Intraoperative adverse events and related postoperative complications in spine surgery: implications for enhancing patient safety founded on evidence-based protocols.

Study Design. Prospective observational study. Objective. To assess the incidence and clinical consequence of intraoperative adverse events from a wide variety of spinal surgical procedures. Summary of Background Data. In this study, adverse events were defined as any unexpected or undesirable event(s) occurring as a result of spinal surgery. A complication was defined as a disease or disorder, which, as a consequence of a surgical procedure, will negatively affect the outcome of the patient. We hypothesized that most adverse events would not result in complications that would be normally flagged through traditional practice audit approaches. By defining the incidence and types of adverse events seen in a spine surgical practice, we hope to develop preventative approaches to enhance patient safety. Methods. All postoperative clinical sequelae (i.e., complications) were prospectively identified, classified as to type, and graded (0 [none] to IV [death]) in 700 consecutive patients who underwent spine surgery (excluding >300-day surgery microdiscectomies) at a university center from January 2002 to June 2003. To confirm data accuracy and assess the clinical sequelae of any adverse events, the medical records of these 700 patients were reviewed. Results. The overall incidence of intraoperative adverse events was 14% (98/700). A total of 23 adverse events led to postoperative clinical sequelae for an overall intraoperative complication incidence of 3.2% (23/700). Specific adverse events included dural tears (n = 58), spinal instrumentation-related events (n = 12), blood loss exceeding 5000 mL (n = 10), anesthesia/medical (n = 4), suspected or actual vertebral artery injury (n = 3), approach-related events (n = 3), esophageal/pharyngeal injury (n = 2), and miscellaneous (n = 6). Conclusions. Adverse events can frequently occur (14%) during spinal surgery, however, the majority (76.5%) are not associated with complications. Improved patient safety can only be maximized by independent practice audit and the development of prospective methods to record adverse event data so that enhanced, evidence-based, clinical protocols can be developed.

Building consensus: development of a Best Practice Guideline (BPG) for surgical site infection (SSI) prevention in high-risk pediatric spine surgery.

Background: Perioperative surgical site infection (SSI) after pediatric spine fusion is a recognized complication with rates between 0.5% and 1.6% in adolescent idiopathic scoliosis and up to 22% in “high risk” patients. Significant variation in the approach to infection prophylaxis has been well documented. The purpose of this initiative is to develop a consensus-based “Best Practice” Guideline (BPG), informed by both the available evidence in the literature and expert opinion, for high-risk pediatric patients undergoing spine fusion. For the purpose of this effort, high risk was defined as anything other than a primary fusion in a patient with idiopathic scoliosis without significant comorbidities. The ultimate goal of this initiative is to decrease the wide variability in SSI prevention strategies in this area, ultimately leading to improved patient outcomes and reduced health care costs. Methods: An expert panel composed of 20 pediatric spine surgeons and 3 infectious disease specialists from North America, selected for their extensive experience in the field of pediatric spine surgery, was developed. Using the Delphi process and iterative rounds using a nominal group technique, participants in this panel were as follows: (1) surveyed for current practices; (2) presented with a detailed systematic review of the relevant literature; (3) given the opportunity to voice opinion collectively; and (4) asked to vote regarding preferences privately. Round 1 was conducted using an electronic survey. Initial results were compiled and discussed face-to-face. Round 2 was conducted using the Audience Response System, allowing participants to vote for (strongly support or support) or against inclusion of each intervention. Agreement >80% was considered consensus. Interventions without consensus were discussed and revised, if feasible. Repeat voting for consensus was performed. Results: Consensus was reached to support 14 SSI prevention strategies and all participants agreed to implement the BPG in their practices. All agreed to participate in further studies assessing implementation and effectiveness of the BPG. The final consensus driven BPG for high-risk pediatric spine surgery patients includes: (1) patients should have a chlorhexidine skin wash the night before surgery; (2) patients should have preoperative urine cultures obtained; (3) patients should receive a preoperative Patient Education Sheet; (4) patients should have a preoperative nutritional assessment; (5) if removing hair, clipping is preferred to shaving; (6) patients should receive perioperative intravenous cefazolin; (7) patients should receive perioperative intravenous prophylaxis for gram-negative bacilli; (8) adherence to perioperative antimicrobial regimens should be monitored; (9) operating room access should be limited during scoliosis surgery (whenever practical); (10) UV lights need NOT be used in the operating room; (11) patients should have intraoperative wound irrigation; (12) vancomycin powder should be used in the bone graft and/or the surgical site; (13) impervious dressings are preferred postoperatively; (14) postoperative dressing changes should be minimized before discharge to the extent possible. Conclusions: In conclusion, we present a consensus-based BPG consisting of 14 recommendations for the prevention of SSIs after spine surgery in high-risk pediatric patients. This can serve as a tool to reduce the variability in practice in this area and help guide research priorities in the future. Pending such data, it is the unsubstantiated opinion of the authors of the current paper that adherence to recommendations in the BPG will not only decrease variability in practice but also result in fewer SSI in high-risk children undergoing spinal fusion. Level of Evidence: Not applicable.

The effect of cyclooxygenase-2 inhibitors on spinal fusion.

Background: Spine surgeons discourage the use of nonsteroidal anti-inflammatory drugs following spine arthrodesis because of their inhibitory effect on bone-healing. To our knowledge, there are no data on the effects of the new cyclooxygenase-2 inhibitors on bone-healing. We undertook this study to determine the effects of these more selective nonsteroidal anti-inflammatory drugs on spinal fusion in a rabbit model. Methods: Seventy-two New Zealand White rabbits underwent a posterolateral intertransverse process arthrodesis with use of autologous iliac crest bone. Sixty-six rabbits survived the surgical procedure and the perioperative period and had an uneventful postoperative course. These rabbits were randomly divided into three groups. One group received 10 mg/kg of celecoxib orally, the second group received 10 mg/kg of indomethacin orally, and the third group (the control group) received 1 cm 3 of saline solution orally. The rabbits received the treatment daily for eight weeks, after which they were killed and the lumbar spine was harvested. The specimens were palpated for motion, radiographed, and prepared for histological analysis. The quality of the fusion was graded at each level by assigning a histological score of 0 to 7. Results: Gross inspection and palpation revealed that 64% (fourteen) of the twenty-two control spines and 45% (ten) of the twenty-two spines in the rabbits treated with celecoxib were fused. With the numbers available, this difference was not significant (p = 0.224). Of the twenty-two spines in the indomethacin-treated rabbits, 18% (four) were fused, and this percentage was significantly different from the control value (p = 0.002). On radiographic assessment, the spine segment was deemed to be fused in 82% (eighteen) of the twenty-two controls, 86% (nineteen) of the twenty-two rabbits treated with celecoxib, and 41% (nine) of the twenty-two indomethacin-treated animals. Only the difference between the indomethacin-treated and control groups was significant (p = 0.004). The histological scores averaged 5.2, 4.8, and 3.5 for the control, celecoxib, and indomethacin groups, respectively. There was a significant difference between the control and indomethacin groups (p = 0.002) but not between the celecoxib and control groups (p = 0.161). Conclusions: These results suggest that celecoxib does not significantly inhibit the rate of spinal fusion in rabbits. They also suggest that the inhibitory effects of nonsteroidal anti-inflammatory drugs on bone-healing are likely mediated by inhibition of cyclooxygenase-1 and that celecoxib is the better choice if treatment with nonsteroidal anti-inflammatory drugs is deemed necessary following spinal arthrodesis.

Intraoperative multimodality monitoring in adult spinal deformity: analysis of a prospective series of one hundred two cases with independent evaluation.

Study Design. A retrospective analysis of prospectively collected data of 102 consecutive adult patients who underwent intraoperative neurophysiological monitoring (IOM) during spinal deformity corrective surgery. Objective. To report the sensitivity and specificity of combined IOM in this study population using the postoperative neurologic examination as the “gold standard.” Summary of Background Data. IOM is recommended during corrective spinal surgery and has been widely used in the pediatric deformity population. However, there are limited data describing the application of IOM in adults undergoing spinal deformity corrective surgery. Methods. The study group consisted of 102 patients undergoing spinal deformity corrective surgery between 2001 and 2004. Patients were monitored using at least 2 or more electrophysiological methods including somatosensory-evoked potentials (SSEP), motor-evoked potentials (MEP), and electromyography (EMG). Results. The mean age of patients was 41.5 years (±17). The majority of the operative procedures involved instrumented fusion from thoracic to lumbar/sacral spine (n = 55), thoracic-pelvis fusion (n = 26), and a combined total of 32 osteotomies (including 25 pedicle subtraction osteotomies and 7 Smith-Peterson osteotomies). SSEPs were recorded successfully in 101 (99%), EMGs in 89 of 102 (87%), and MEPs in 12 of 16 (75%). Five cases were true positives (4.95%), and these were all detected by combined monitoring (2-SSEP, 2-EMG, 1-MEP). There were no false positives with SSEPs, but EMG resulted in 30 of 89 (34%) false positives. There were 4 false negatives with SSEPs, which reduced its sensitivity to 33%. There was 1 false negative with EMG, and 0 with MEPs. When these results were collated, the overall sensitivity of combined multimodality IOM in this adult deformity series was 100%, specificity 84.3%, PPV 13.9%, and NPV 97%. The combined sensitivity in the osteotomy group (n = 32) was 67%, specificity 98%, PPV 80%, and NPV 96%. In comparison, there were no IOM abnormalities in those patients who had in situ/minor corrective procedures (n = 18; largely adult degenerative scoliosis). Conclusion. Multimodality IOM of spinal cord sensory and motor function during surgical correction of adult spinal deformity is feasible and provides useful neurophysiological data with an overall sensitivity of 100% and a specificity of 84.3% (67% and 98%, respectively in patients undergoing major deformity correction).

Treatment of spinal stenosis and fixed sagittal imbalance.

Most commonly, sagittal imbalance associated with stenosis is seen with a hypolordotic fusion mass, junctional kyphosis, and junctional stenosis. If the deformity is flexible, it can be treated with anterior and posterior fusion with anterior structural grafting. If it is fixed, which it usually is, then a pedicle subtraction procedure with decompression and extension of the fusion usually is the most suitable operative approach.

Time-Dependent Inhibitory Effects of Indomethacin on Spinal Fusion

Background: The use of nonsteroidal anti-inflammatory drugs following spine arthrodesis is discouraged because of the negative effects on bone-healing. We are not aware of any data regarding when nonsteroidal anti-inflammatory drugs may be safely resumed postoperatively. We hypothesized that these drugs have a time-dependent deleterious effect on fusion, with the greatest inhibition during the early phases of fusion.Methods: Seventy New Zealand White rabbits underwent posterior intertransverse process arthrodesis at L5-L6 with use of iliac autograft. Rabbits randomly received indomethacin (10 mg/kg orally) starting at two weeks after surgery (twenty-four animals), indomethacin starting at four weeks postoperatively (twenty-three), or saline starting at two weeks postoperatively (twenty-three) (the control group). The animals were killed at six weeks, and the spines were denuded of soft tissues and palpated for L5-L6 motion. Fusion was defined as the complete absence of motion.Results: Sixty-five percent (fifteen) of the twenty-three spines in the control group and 48% (eleven) of the twenty-three in the four-week group fused. However, only 21% (five) of the twenty-four spines in the two-week group fused. The difference between the two-week and control groups was significant (p < 0.002), as was the difference between the two and four-week groups (p = 0.05). The difference between the four-week and control groups was not significant (p = 0.2).Conclusions: The earlier that indomethacin was resumed postoperatively, the greater was its negative effect on fusion. Indomethacin appears to play a significant inhibitory role in the early phase of healing. Initiating indomethacin treatment in the latter phase of healing does not appear to significantly affect fusion rates, although there was a nonsignificant trend toward inhibition. To our knowledge, this is the first investigation of the time-dependent nature of indomethacins effect on bone-healing.Clinical Relevance: Our data suggest that caution be used when initiating nonsteroidal anti-inflammatory drugs after spinal arthrodesis, particularly in the early phase of healing.