Intraoperative spinal cord monitoring during the surgical correction of scoliosis due to cerebral palsy and other neuromuscular disorders

Surgical complications in neuromuscular scoliosis surgery: systematic review and meta-analysis of the last ten years

PURPOSE

Surgical correction of neuromuscular scoliosis is often a challenging and extensive procedure. Due to this complexity and the high disease burden that these patients carry, per and post-operative complications are not uncommon. The purpose of this study was to systematically review and describe the pooled rates of postoperative complications and analyze risk factors for complications in neuromuscular scoliosis surgery described in the literature in the last ten years.

METHODS

A systematic review of the English literature across multiple databases was conducted using search criteria (neuromuscular scoliosis AND complications) and using PRISMA guidelines (Jan 2012-July 2022). Studies with less than 30 patients and follow-up of < 2 years were excluded. Data extraction and meta-analysis were performed using random mode effect. Statistical analysis was conducted using OpenMeta software. Meta-regression analysis was used to detect risk factors (surgical approach, intraoperative time, intraoperative blood loss, preoperative Cobb angle and patient diagnosis) associated with each complication group. Confidence interval (CI) was set at 95%.

RESULTS

Twenty-two studies met the inclusion criteria involving 2155 patients. The level of evidence among studies were III (9) and IV (13). The most common primary diagnosis was cerebral palsy (43%) followed by Duchenne muscle dystrophy (20%), myelomeningocele (7.4%), spinal muscle atrophy (7.1%), Rett syndrome (< 2%) and combined other pathologies (20.2%). The pooled incidence rate of wound complications was the highest, amongst all complications, at 13.3% (CI 10.838 to 16.861); closely followed by respiratory complications (11.8%;CI 5.7 to 19.7). Implant failure occurred in 7.1% cases (CI 6.418 to 11.465), gastrointestinal complications was 5.2%; CI 2.4 to 8), pseudarthrosis in (4.6%;CI 2.2 to 6.9) and neurological deficit in 2.9% (CI 1.989 to 6.086). The pooled rate of revision surgery was (9.6%; CI 6.2 to 12.9). Heterogeneity was assessed using I2 test which results were moderately heterogeneous. Meta-regression analysis revealed that the diagnosis of myelomeningocele or Duchenne muscle dystrophy or spinal muscle atrophy were strongly associated with wound and respiratory complications (p = 0.007 and p = 0.005, respectively).

CONCLUSION

Wound-related (13.3%) and respiratory complications (11.8%) remain the most common complications among studies after corrective surgery for neuromuscular scoliosis. Both are significantly associated with Duchenne muscle dystrophy, spinal muscle atrophy and myelomeningocele.

Neuromonitoring Changes in Spinal Deformity Surgery

Spinal cord injury is one of the most feared complications in spinal deformity surgery. The surgeon must be vigilant of direct and indirect sources of injury at all points during surgery. The incidence of complications has greatly decreased with the ability to monitor the motor and sensory pathways. Changes in signaling of these pathways provide context for what the insult is, and how to correct it before it becomes irreversible. There are well-established protocols that provide an algorithmic response to changes that can help all in the room determine the source of injury, and the appropriate reaction.

Transcranial electric motor evoked potential monitoring during scoliosis surgery in children with cerebral palsy and active seizure disorder: is it feasible and safe?

PURPOSE

Use of spinal cord monitoring in children with cerebral palsy (CP) and neuromuscular scoliosis is challenging. The previous reports suggest low success rates in the setting of CP, and it is unclear if transcranial electric motor evoked potentials (TcMEP) monitoring is contraindicated in patients with an active seizure disorder. The purpose of this study was to determine (1) are patients with CP able to be appropriately monitored with TcMEP? and (2) does TcMEP cause an increase in seizure activity?

METHODS

This was an institutional review board-approved retrospective cohort study observing 304 patients from 2011 to 2020. Inclusion criteria included all patients with CP undergoing posterior spinal fusion during this time. Intraoperative data were examined for the ability to obtain monitoring and any intraoperative events. Patients were followed for 3 months postoperatively to determine any increase in seizure activity that could have been attributed to the TcMEP monitoring.

RESULTS

Of the 304 patients who were observed, 21% (20.8%) were unable to be monitored due to lacking baseline signals from the extremities. Seventy-seven percent (77.5%) were successfully monitored with TcMEP. For these patients, no increased seizure activity was documented either intra- or postoperatively.

CONCLUSION

A high percentage of children (77.5%) with CP were able to be successfully monitored with TcMEP during posterior spinal fusion. Furthermore, the concerns about increased seizure activity after TcMEP were not supported by the data from this cohort. Technical details of successful neuromonitoring in these patients are important and included increased stimulation voltage requirements and latency times.

LEVEL OF EVIDENCE

III retrospective comparative study.

Neuromuscular Monitoring and Wake-Up Test During Scoliosis Surgery

A typical spine is straight and symmetrical, with all of the vertebrae facing forward when viewed from the posterior. Scoliosis is a term used to describe a lateral deviation of the spine's normal vertical line that is greater than 10° on an X-ray. More severe curves are sometimes accompanied by medical issues such as increased back discomfort and cardiorespiratory difficulties along with the cosmetic components of the deformity. The test for spinal cord integrity prior to the widespread adoption of intraoperative neurophysiologic monitoring (IOM) was the wake-up test. In this article, we review the challenges faced by anesthesiologists and surgeons during intraoperative monitoring and the importance of clinical assessment of surgical outcomes.

Intra-Operative Neurophysiological Monitoring in Patients with Thoracic Spinal Stenosis: Its Feasibility and High-Risk Factors for New Neurological Deficit

OBJECTIVE

Considering the high risk of postoperative neurological complications for patients with thoracic spinal stenosis (TSS), intra-operative neurophysiological monitoring (IONM) has been used for detecting possible iatrogenic injury timely. However, the IONM waveforms are often unreliable. This article is designed to determine the test performance of somatosensory evoked potentials (SEP) and motor evoked potentials (MEP) during surgical thoracic decompression in patients with TSS, and to investigate the risk factors associated with deteriorated neurologic function at immediate postoperation.

METHODS

Patients undergoing posterior spinal fusion from February 2009 to December 2020 were retrospectively reviewed. Patients were divided into the deteriorated neurologic function (DNF) group and the improved/intact neurological function (INF) group based on the postoperative neurological status. Demographic parameters such as gender, age, height, weight, etiology and IONM data were compared between groups. Demographics and IONM data between DNF and INF groups were compared by independent t or nonparametric tests. The incidence of abnormal SEP was analyzed by Chi-square test.

RESULTS

A total of 108 patients (63 males, 45 females) with an average age of 53.5 ± 14.0 years were included. The SEP and MEP records were available in 94 and 98 patients, with the overall success rates being 87.0% and 90.7%, respectively. The sensibilities and specificities were 100% and 88.2% for SEP, 100% and 98.8% for MEP, respectively. There were 17 patients in DNF group and 91 patients in INF group. High weight (79.1 ± 14.6 vs 69.7 ± 15.7 kg, P = 0.024), high inter-side difference of MEP amplitude (899.1 ± 997.5 vs 492.3 ± 512.4 μV, P = 0.013) and high incidence of abnormal SEP (94.1% vs 64.8%, P = 0.024) were observed in the DNF group. Fourteen (82.4%) patients in the DNF group showed improvement in neurological status during follow-up.

CONCLUSIONS

The overall success rates were 87.0% for SEP and 90.7% for MEP in patients with TSS.

Intra-Operative Neurophysiological Monitoring in Patients with Intraspinal Abnormalities Undergoing Posterior Spinal Fusion

OBJECTIVE

To analyze the intraoperative neurophysiological monitoring (IONM) data of patients with intraspinal abnormalities undergoing posterior spinal fusion and to determine how intraspinal abnormalities influence IONM results.

METHODS

Patients with severe kyphoscoliosis and intraspinal abnormalities who underwent posterior spinal correction and fusion between September 2015 and January 2019 were retrospectively reviewed. Candidate intraspinal abnormalities included Chiari malformation, syringomyelia, split cord malformation, and tethered cord syndrome. Total intravenous anesthesia was administered, and no muscle relaxant or inhalation anesthesia was used for maintenance. IONM data, including somatosensory evoked potentials (SSEP) and motor evoked potentials (MEP), were recorded. The P37 and N50 latencies and amplitude were recorded for SSEP, whereas only the amplitude was recorded for MEP. The possible high-risk factors for abnormal IONM results were analyzed.

RESULTS

The current study included 87 patients (40 men, 47 women) with an average age of 20.2 ± 10.4 years. The etiologies were neuromuscular in 45 patients, idiopathic in four, and congenital in 38. A total of 136 intraspinal abnormalities were detected, including Chiari malformation in 33 patients, syringomyelia in 55, split-cord malformation in 25, and tethered cord syndrome in 23. Forty patients had one intraspinal abnormality, whereas 47 patients had two or three intraspinal abnormalities. The monitorabilities were 87.4% and 97.7% for the SSEP and MEP, respectively. SSEP alerts were reported in five patients and MEP alerts in four patients, and new neurological deficits were observed in three patients postoperatively. The sensitivity and specificity were 100% and 97.3% for SSEP, and 100% and 98.8% for MEP, respectively. A significant difference in MEP amplitude between the concave and convex sides was observed, while significantly higher SSEP latency was observed on the concave side in patients with preoperative neurological deficits. There were 52 (59.8%) patients with abnormal IONM data. Preoperative neurological deficits (χ²  = 7.715, p = 0.005) and more than one intraspinal abnormality (χ²  = 9.186, p = 0.004) indicated a higher risk of abnormal IONM data.

CONCLUSIONS

IONM can be effectively used in patients with intraspinal abnormalities who undergo posterior spinal fusion. Patients with preoperative neurological deficits and more than one intraspinal abnormality have a higher risk of abnormal IONM monitoring.

Perioperative Optimization of Patients With Neuromuscular Disorders Undergoing Scoliosis Corrective Surgery: A Multidisciplinary Team Approach

STUDY DESIGN

Narrative review.

OBJECTIVE

The high rate of complications associated with the surgical management of neuromuscular spinal deformities is well documented in the literature. This is attributed to attenuated protective physiological responses in multiple organ systems.

METHODS

Review and synthesis of the literature pertaining to optimization of patients with neuromuscular scoliosis undergoing surgery. Our institutional practice in the perioperative assessment and management of neuromuscular scoliosis is also described along with a clinical vignette.

RESULTS

Respiratory complications are the most common to occur following surgery for neuromuscular disorders. Other categories include gastrointestinal, cardiac, genitourinary, blood loss, and wound complications. A multidisciplinary approach is required for perioperative optimization of these patients and numerous strategies are described, including respiratory management.

CONCLUSION

Perioperative optimization for patients with neuromuscular disorders undergoing corrective surgery for spinal deformity is multifaceted and complex. It requires a multidisciplinary evidence-based approach. Preadmission of patients in advance of surgery for assessment and optimization may be required in certain instances to identify key concerns and formulate a tailored treatment plan.

Intra-operative neurophysiological monitoring in patients with dystrophic neurofibromatosis type 1 scoliosis

OBJECTIVE

To analyse the intra-operative neurophysiological monitoring (IONM) data in patients with dystrophic neurofibromatosis type 1 (NF1) associated scoliosis, and to investigate the possible risk factors for failed IONM monitoring.

METHODS

Patients undergoing posterior spinal fusion from September 2015 to December 2019 were retrospectively reviewed. The latency (P37, N50) and amplitude of somatosensory evoked potentials (SEP) in bilateral lower extremities, latency and amplitude of motor evoked potentials (MEP) in bilateral lower extremities and unilateral upper extremity were recorded. The neurological status, curve pattern, Cobb angle of main curve, vertebral rotatory subluxation and dystrophic features at pre-operation were assessed for each patient. The failed IONM monitoring was defined as no reliable SEP or MEP waveforms of all monitored muscles.

RESULTS

A total of 92 patients (53 M, 39 F) with an average age of 14.1 ± 2.7 years were included. Failed IONM monitoring was identified in 17 patients with overall success rates being 87.0 and 94.6% for SEP and MEP. The average P37 latency, N50 latency, SEP amplitude and MEP latency showed no significant difference between concave and convex sides (p > 0.05 for all). The MEP amplitudes of lower extremities were lower on concave side than convex side (334.5 ± 291.9 µV VS 417.5 ± 380.5 µV, p = 0.030). Higher risk of failed IONM monitoring was found in patients with neurological deficit (p = 0.014) and more dystrophic features (p = 0.002) at pre-operation.

CONCLUSIONS

The overall success rates were 87.0% for SEP and 94.6% for MEP in patients with NF1-associated scoliosis. Neurological deficit and more dystrophic features at pre-operation indicated higher risk of failed IONM monitoring.

Intraoperative neurophysiological monitoring during scoliosis surgery in patients with Duchenne muscular dystrophy

PURPOSE

Little is known about the reliability and value of intraoperative neurophysiological monitoring (IONM) in patients with Duchenne muscular dystrophy (DMD) undergoing scoliosis correction surgery. The aim of this study was to investigate the feasibility of IONM and the cortical excitability in these patients.

METHODS

Fifteen patients with DMD and scoliosis and 15 patients with adolescent idiopathic scoliosis (AIS) underwent scoliosis correction surgery with the use of IONM. IONM consisted of transcranial electrical stimulation motor evoked potential (Tc-MEP) and somatosensory evoked potential (SSEP) monitoring. The highest Tc-MEP amplitudes were collected to test the feasibility. Preoperative compound muscle action potentials (CMAPs) and transcranial magnetic stimulation (TMS)-MEPs were recorded to test the cortical excitability. SSEPs were scored as elicitable or not elicitable.

RESULTS

Tc-MEP amplitudes were significantly lower in the DMD group for both the gastrocnemius and tibialis anterior muscles. However, the abductor hallucis muscle had similar amplitudes in both the DMD as the AIS group. TMS/CMAP and Tc-MEP/CMAP ratios were similar in the DMD and AIS group (P = 0.126 and P = 0.792 respectively).

CONCLUSIONS

Tc-MEP and SSEP monitoring is feasible, particularly when Tc-MEPs are recorded from the abductor hallucis muscle in patients with DMD. Similar TMS/CMAP and Tc-MEP/CMAP ratios show that there were no differences observed in cortical excitability between the groups. IONM seems a feasible and valuable neurophysiological tool to signal possible surgically induced damage to the spinal cord during scoliosis correction surgery in patients with DMD.

Technical aspects of surgical correction of spinal deformities in cerebral palsy

PURPOSE

Cerebral palsy (CP) is a disorder arising from a non-progressive lesion in the developing immature brain with an encephalopathy, that results in various levels of motor and sensory dysfunction. Motor disability of these children can be assessed by the Gross Motor Function Classification System in five levels, and depending on their motor functional capability, the most severely affected children fall into levels IV and V. Children in groups IV and V present a full spectrum of musculoskeletal deformities, among which, scoliosis is the most frequently found spinal deformity that most often requires surgical treatment. However, these are procedures that are usually technically demanding, requiring experienced surgical teams and a multidisciplinary approach.

METHODS

In order to overcome some of the technical pitfalls that may complicate these complex surgical procedures, the authors have gathered together different tips and tricks that may help surgeons performing surgical correction of spinal deformities in CP children.

CONCLUSION

Although for these children surgery is a major undertaking, with the multidisciplinary approach and advances of technology, anaesthesia and optimization of pre- and postoperative care, complications are manageable in most cases, improving not only the outcome of surgery but also the patient's quality of life and satisfaction of parents and caretakers.

An evaluation of anesthetic fade in motor evoked potential monitoring in spinal deformity surgeries

Background

Intraoperative neuromonitoring using motor evoked potentials (MEP) satisfactorily detects motor tract integrity changes during spinal surgery. However, monitoring is affected by “anesthetic fade,” in which the stimulation threshold increases because the waveform amplitude decreases with the accumulation of propofol. Therefore, the purpose of this study was to clarify the effect of anesthetic fade on transcranial MEPs by investigating the time-dependent changes of amplitude during spinal deformity surgeries.

Methods

We retrospectively reviewed medical records of 142 spinal deformity patients (66 patients with idiopathic scoliosis, 28 with adult spinal deformities, 19 with neuromuscular scoliosis, 17 with syndromic scoliosis, and 12 with congenital scoliosis). The average age was 28 years (range, 5 to 81 years). MEPs were recorded bilaterally from the abductor digiti minimi (ADM) and abductor hallucis (AH) muscles during spinal deformity surgeries. The Wilcoxon signed-rank test was used to investigate the time-dependent changes of amplitude after propofol infusion to evaluate anesthetic fade effects.

Results

The average time to baseline from initial propofol infusion was 113 min (range, 45 to 182 min). In the ADM, the amplitude was 52% at 1 h after initial propofol infusion, 102% at 2 h, 105% at 3 h, 101% at 4 h, 86% at 5 h, and 81% at 6 h. Compared to the 2-h time point, MEP decreased significantly by 16% at 5 h (P < 0.0005) and by 21% at 6 h (P < 0.05). In the AH, the amplitude was 49% at 1 h after initial infusion of propofol, 102% at 2 h, 102% at 3 h, 92% at 4 h, 71% at 5 h, and 63% at 6 h. Compared to the 2-h time point, MEP decreased significantly by 10% at 4 h (P < 0.005), by 31% at 5 h (P < 0.0000005), and by 39% at 6 h (P < 0.05).

Conclusions

MEP amplitude significantly decreased in the upper limbs at 5 and 6 h and in the lower limbs at 4, 5, and 6 h after the initial infusion of propofol, respectively. The influence of anesthetic fade could influence false positive MEPs during long spinal surgeries.

Minimally Invasive Surgery for Neuromuscular Scoliosis: Results and Complications in a Series of One Hundred Patients

STUDY DESIGN

A retrospective review.

OBJECTIVE

To report the results of an alternative technique using a minimally invasive fusionless surgery. The originality is based on the progressive correction of the deformities with proximal and distal fixation and on the reliability of the pelvic fixation using iliosacral screws on osteoporotic bones.

SUMMARY OF BACKGROUND DATA

Spinal deformities are common in neuromuscular diseases. Conventional treatment involves bracing, followed by spinal instrumented fusion. Growing rod techniques are increasingly advocated but have a high rate of complications.

METHODS

The technique relies on a bilateral double rod sliding construct anchored proximally by four hooks claws and distally to the pelvis by iliosacral screws through a minimally invasive approach. Hundred patients with neuromuscular scoliosis underwent the same fusionless surgery extended from T1 to the pelvis. The average age at initial surgery was 11 + 6 years. Diagnoses included cerebral palsy (61), spinal muscular atrophy (22), muscular dystrophy (10), and other neurological etiologies (7). Cobb angle and pelvic obliquity were measured before and after initial surgery, and at final follow-up. Complications were reviewed.

RESULTS

At latest follow-up 3 + 9 years (range 2 yr-6 + 3 yr), the mean Cobb angle improved from 89° to 35° which corresponds to 61% correction. Mean pelvic obliquity improved from 29° to 5°, which corresponds to 83% correction. Mean T1-S1 length increased from 30.02 to 37.28 cm. Mean preoperative hyper kyphosis was reduced from 68.44° to 33.29°. Complications occurred in 26 patients including mechanical complications (12) and wound infections (16). No arthrodesis was required at last follow-up.

CONCLUSION

This original fusionless technique is safe and effective, preserving spinal and thoracic growth. It provides a significant correction of spinal deformities and pelvic obliquity with a reduced complications rate. The strength and stability of this modular construct over time allow the avoidance of final arthrodesis.

LEVEL OF EVIDENCE

4.

Gastrointestinal Complications After Surgical Correction of Neuromuscular Scoliosis: A Retrospective Cohort Study

STUDY DESIGN

A retrospective cohort study of consecutively operated neuromuscular scoliosis patients.

BACKGROUND AND AIM

Surgical correction of neuromuscular scoliosis can be complicated by early gastrointestinal complications, but data on the extent and severity of them is scarce. The aim of the study was to determine the incidence, course, and risk factors of gastrointestinal complications after neuromuscular scoliosis correction.

MATERIAL AND METHODS

Ninety-one patients (<21 years of age) were consecutively operated on for neuropathic neuromuscular scoliosis during 2000-2011. Patients who developed marked postoperative gastrointestinal complications were identified and clinical, operative, and radiographic records, death certificates, and post-mortem reports were examined.

RESULTS

The average age at surgery was 14.5 (SD 2.9) and follow-up time was 4.9 (SD 2.3) years. Gastrointestinal complications occurred in 12 (13%) patients and included prolonged paralytic ileus (7%, 6/91), dysphagia (7%, 6/91), and gastroparesis (1%, 1/91). Hospital stay was 22 (SD 11) days in patients with gastrointestinal complications and 16 (SD 20) days in non-complicated patients (p = 0.005). Dysphagia required permanent feeding gastrostomy in one patient whereas other complications were transient and none caused death. The risk factors for postoperative gastrointestinal complications were preoperative main curve correction <30% in traction/bending radiographs (Relative Risk (RR) = 28 (95% Confidence Interval (CI) 4.4-180); p < 0.001), preoperative main curve >90° (RR = 5.5 (95% CI 1.3-23); p = 0.020), disturbance in intraoperative spinal cord monitoring (RR = 6.0 (95% CI 1.1-34); p = 0.043), and intravenous opioid medication over 5 days postoperatively (RR = 7.9 (95% CI 1.8-35), p = 0.006).

CONCLUSION

Gastrointestinal complications occurred in 13% of patients after neuromuscular scoliosis correction. Marked gastrointestinal complications extended postoperative hospitalization period, but they were transient in majority (92%) of cases and none caused death. Rigid scoliosis was the most significant risk factor for gastrointestinal complications. Gastrointestinal complications appear to be less frequent after posterior only spinal fusion with total pedicle screw instrumentation and Ponte osteotomies.

What's New in the Management of Neuromuscular Scoliosis

BACKGROUND

Patients with neuromuscular scoliosis (NMS) can pose treatment challenges related to medical comorbidities and altered spinopelvic anatomy. We reviewed the recent literature regarding evaluation and management of NMS patients and explored areas where further research is needed.

METHODS

We searched the PubMed database for all papers related to the treatment of NMS published from January 1, 2011 through July 31, 2014, yielding 70 papers.

RESULTS

A total of 39 papers contributed compelling new findings. Steroid treatment has been most promising in patients with Duchenne muscular dystrophy, leading to a significantly lower death rate, better pulmonary function, and longer independent ambulation. Growing rods in early-onset NMS were shown to result in significant improvements in major Cobb angles and pelvic obliquity, with low complication rates in patients with spinal muscular atrophy but high infection rates in those with cerebral palsy. Early reports of magnetic growing rods in NMS patients are favorable. Intraoperative neural monitoring is variable in this patient population; however, use of transcranial motor-evoked potentials in NMS patients seems to be safe. Blood loss is the highest in NMS patients when compared with all other diagnostic categories. However, tranexamic acid seems to significantly lower intraoperative blood loss. In a multicenter study, patients diagnosed with NMS had the highest surgical-site infection rate at 13.1%. Best-practice guidelines have been created regarding prevention of infection in NMS patients. Preoperative nutritional optimization and postoperative nutritional supplementation seem to help with lowering the infection rate in these patients.

CONCLUSIONS

There have been major advances in the management of NMS patients, but many challenges remain. Further multicenter studies and randomized clinical trials are needed, particularly in the areas of infection prophylaxis, nutritional optimization, improvement in intraoperative neural monitoring, and prevention of proximal junctional kyphosis.

LEVEL OF EVIDENCE

Level 4-literature review.

Spinal fusion for pediatric neuromuscular scoliosis: national trends, complications, and in-hospital outcomes

OBJECTIVE The objective of this study was to determine if the recent changes in technology, surgical techniques, and surgical literature have influenced practice trends in spinal fusion surgery for pediatric neuromuscular scoliosis (NMS). In this study the authors analyzed recent trends in the surgical management of NMS and investigated the effect of various patient and surgical factors on in-hospital complications, outcomes, and costs, using the Nationwide Inpatient Sample (NIS) database. METHODS The NIS was queried from 2002 to 2011 using International Classification of Diseases, Ninth Edition, Clinical Modification codes to identify pediatric cases (age < 18 years) of spinal fusion for NMS. Several patient, surgical, and short-term outcome factors were included in the analyses. Trend analyses of these factors were conducted. Both univariate and multivariable analyses were used to determine the effect of the various patient and surgical factors on short-term outcomes. RESULTS Between 2002 and 2011, a total of 2154 NMS fusion cases were identified, and the volume of spinal fusion procedures increased 93% from 148 in 2002 to 286 in 2011 (p < 0.0001). The mean patient age was 12.8 ± 3.10 years, and 45.6% of the study population was female. The overall complication rate was 40.1% and the respiratory complication rate was 28.2%. From 2002 to 2011, upward trends (p < 0.0001) were demonstrated in Medicaid insurance status (36.5% to 52.8%), presence of ≥ 1 comorbidity (40.2% to 52.1%), and blood transfusions (25.2% to 57.3%). Utilization of posterior-only fusions (PSFs) increased from 66.2% to 90.2% (p < 0.0001) while combined anterior release/fusions and PSF (AR/PSF) decreased from 33.8% to 9.8% (< 0.0001). Intraoperative neurophysiological monitoring (IONM) underwent increasing utilization from 2009 to 2011 (15.5% to 20.3%, p < 0.0001). The use/harvest of autograft underwent a significant upward trend between 2002 and 2011 (31.3% to 59.8%, p < 0.0001). In univariate analysis, IONM use was associated with decreased complications (40.7% to 33.1%, p = 0.049) and length of stay (LOS; 9.21 to 6.70 days, p <0.0001). Inflation-adjusted mean hospital costs increased nearly 75% from 2002 to 2011 ($36,805 to $65,244, p < 0.0001). In the multivariable analysis, nonwhite race, highest quartile of median household income, greater preexisting comorbidity, long-segment fusions, and use of blood transfusions were found to increase the likelihood of complication occurrence (all p < 0.05). In further multivariable analysis, independent predictors of prolonged LOS included older age, increased preexisting comorbidity, the AR/PSF approach, and long-segment fusions (all p < 0.05). Lastly, the likelihood of increased hospital costs (at or above the 90th percentile for LOS, 14 days) was increased by older age, female sex, Medicaid insurance status, highest quartile of median household income, AR/PSF approach, long-segment fusion, and blood transfusion (all p < 0.05). In multivariable analysis, the use of autograft was associated with a lower likelihood of complication occurrence and prolonged LOS (both p < 0.05). CONCLUSIONS Increasing use of IONM and posterior-only approaches may combat the high complication rates in NMS. The trends of increasing comorbidities, blood transfusions, and total costs in spinal fusion surgery for pediatric NMS may indicate an increasingly aggressive approach to these cases.

Early limited instrumentation of scoliosis in Duchenne muscular dystrophy: is a single-rod construct sufficient?

BACKGROUND CONTEXT

Correction of scoliotic deformity in Duchenne muscular dystrophy (DMD) is performed to maintain adequate seating posture and facilitate comfort. Delaying surgery can predispose to greater morbidity as DMD exhibits progressive cardiorespiratory compromise. Early limited instrumentation may provide a solution to optimize patients with this condition.

PURPOSE

The aim was to assess outcomes for a cohort of DMD patients who had posterior single-rod instrumentation and bilateral spinal fusion of their neuromuscular scoliotic deformity.

STUDY DESIGN

This was a retrospective cohort study.

PATIENT SAMPLE

Forty-one consecutive patients were included.

OUTCOME MEASURES

Perioperative morbidity, seating outcomes, pulmonary function, deformity correction, and instrumentation integrity were assessed.

METHODS

Clinical and radiographic review was performed.

RESULTS

No perioperative mortality or neurologic deterioration was encountered. Total surgical time was 96 minutes, mean total blood loss was 2.3l, mean intensive care unit stay was 41 hours, and overall length of stay was 11 days. Mean Cobb angle improved from 24.3° to 15.6°, pelvic obliquity improved from 7° preoperatively to 5° postoperatively. Three patients had failure of fixation at a mean of 3.5 years. Forced vital capacity was 60% preoperatively and 56% at 1 year, forced expiratory volume/1 second was 67% and 62% at 1 year postoperatively. Seating and posture was satisfactory in all these patients.

CONCLUSIONS

The authors advocate early operative intervention using a limited instrumentation technique in patients with DMD to maintain seating balance and minimize perioperative morbidity.

Complications and outcomes of complex spine reconstructions in poliomyelitis-associated spinal deformities: a single-institution experience

STUDY DESIGN

Retrospective case series.

OBJECTIVE

To share our institutional experience with spinal reconstruction for deformity correction in patients with a history of poliomyelitis.

SUMMARY OF BACKGROUND DATA

Polio and postpolio syndrome are not uncommonly related to a paralytic spinal deformity. Limited modern data exist regarding outcomes and complications after spinal reconstruction in this population.

METHODS

A clinical database was reviewed for patients undergoing spinal reconstruction for polio-associated spinal deformity at our institution from 1985 to 2012. Relevant demographic, medical, surgical, and postoperative information were collected from medical records and analyzed. Preoperative and last follow-up Scoliosis Research Society-22 Questionnaire scores were recorded.

RESULTS

A total of 22 patients with polio who underwent surgical deformity correction were identified. Mean age was 49 years (range, 12-74 yr), and 15 patients (68%) were female. Preoperative motor deficit was present in 14 of 22 (64%) patients. All patients underwent instrumented spinal fusion (mean, 13 vertebral levels, range, 3-18). Ten (10/22, 45%) patients developed major complications, and 4 patients (4/22, 18%) developed new postoperative neurological deficits. Neurological monitoring yielded a 13% false-negative rate. At 2-year follow-up, 20 of 22 patients maintained an average coronal correction of 25° (33%, P = 0.001) and sagittal correction of 25° (34%, P = 0.003). Minimum 2-year follow-up data were available for 11 of 22 (50%) patients. At an average of 72 months of follow-up (range, 28-134 mo), the mean Scoliosis Research Society-22 Questionnaire pain subscore improved from a mean of 2.75 to 3.6 (P = 0.012); self-image from 2.8 to 3.7 (P = 0.041); function from 3.1 to 3.8 (P = 0.036); satisfaction from 2.1 to 3.9 (P = 0.08); and mental health from 3.7 to 4.5 (P = 0.115).

CONCLUSION

Spine reconstruction for poliomyelitis-associated deformity was associated with high complication rates (54%) and sometimes unreliable neurological monitoring data. Despite this, patients undergoing spine reconstructions had significantly improved outcome scores. These data may help surgeons to appropriately counsel this complicated patient population.

Calcified giant thoracic disc herniations: considerations and treatment strategies

INTRODUCTION

Giant herniated thoracic discs (GHTD) remain a surgical challenge. When combined with calcification, these discs require altered surgical strategies and have only been infrequently described. Our objective was to describe our surgical approaches in the management of calcified GHTD.

METHODS

This was a retrospective cohort study of all patients with calcified GHTD operated between 2004 and 2012. Data were collected from review of patients' notes and radiographs and included basic demographic and radiological data, clinical presentation and outcome, operative procedure and complications.

RESULTS

During the study period, there were 13 patients with calcified GHTD, including 6 males and 7 females (mean age 55 years, range 31-83 years). The average canal encroachment was 62% (range 40-90%); mean follow-up 37 months (12-98). All patients were treated with anterior thoracotomy, varying degrees of vertebral resection, removal of calcified disc and with or without reconstruction. The average time for surgery was 344 min (range 212-601 min) and estimated blood loss 1,230 ml (range 350-3,000 ml). Post-operatively, 8 patients improved by 1 Frankel grade (62%), 2 improved by 2 grades (15%) and 3 did not change their grade (23%). The complication rate was 4/13 (31%; 3 patients with durotomies (2 incidental, 1 intentional) and 1 with recurrence).

DISCUSSION

Calcified GHTD remain a surgical challenge. Anterior decompression through a thoracotomy approach, and varying degrees of vertebral resection with or without reconstruction allowed us to safely remove the calcified fragment. All patients remained the same (23%) or improved by at least 1 grade (77%) neurologically, without radiographic failure at final follow-up.

Surgical correction of scoliosis in Rett syndrome: cord monitoring and complications

AIM

Rett syndrome is a progressive neurodevelopmental disorder that predominantly affects females and is associated with a high incidence of scoliosis and epilepsy. There is scant published work about intraoperative spinal cord monitoring in these patients and little more regarding the rate of perioperative complications. We investigated our institutions' experience with both.

METHODS

We retrospectively reviewed the records of 11 patients with Rett syndrome who underwent surgical correction of scoliosis at our institution between 2004 and 2010.

RESULTS

Eleven patients underwent successful correction of their scoliosis at an average age of 12. Eight of the patients suffered one or more significant complications. The average curve was corrected from 71° to 27°. Successful spinal cord monitoring was achieved in eight of the nine patients where it was attempted. No patient suffered any neurological complications. Average inpatient stay was 18.2 days.

CONCLUSION

Scoliosis surgery in patients with Rett syndrome carries a very high rate of complications and an average hospital stay approaching 3 weeks. Both caregivers and surgeons should be aware of this when planning any intervention. These patients frequently have useful lower limb function and spinal cord monitoring is a valid tool to aid in its preservation. We would suggest aggressive optimisation of these patients prior to surgery, with an emphasis on nutrition.

Neuromonitoring for scoliosis surgery

The use of intraoperative neuromonitoring (IONM) during pediatric scoliosis repair has become commonplace to reduce the risk of potentially devastating postoperative neurologic deficits. IONM techniques include somatosensory evoked potentials, motor evoked potentials, electromyography, and intraoperative wake-up tests. Special considerations for scoliosis repair in pediatric patients include preexisting neurologic deficits and young patients with immature neural pathways in whom neurophysiologic monitoring may prove difficult or unreliable.

Revision of surgical correction of scoliosis in pediatric patients affected by neuromuscular pathology using Unit Rod instrumentation

PURPOSE

The purpose of this study is to present a large consecutive series of pediatric patients affected by neuromuscular scoliosis treated with Unit Rod instrumentation.

METHODS

Retrospective review of 160 children treated with Unit Rod instrumentation between 2003 and 2010. This review analyzed complications, radiographic outcome, time surgery, average blood loss, hospital staying and functional outcome of patients and parents after surgery. The follow-up of 80 patients is at more than 5 years.

RESULTS

Scoliosis was corrected from a mean of 56° range 21° to 76° Cobb (68 %). Pelvic obliquity was corrected from a mean of 24° to 5° (74 %). Major complications are not related to the technique but to the pathology.

CONCLUSION

Unit Rod instrumentation is a common standard technique, is considerably less expensive than the other system, and remains a good indication for the treatment of the spinal deformity in children affected by neuromuscular disease.