Ian G. Dorward

Osteotomies in the posterior-only treatment of complex adult spinal deformity: a comparative review

In addressing adult spinal deformities through a posterior approach, the surgeon now may choose from among a variety of osteotomy techniques. The Ponte or Smith-Petersen osteotomy provides the least correction, but it can be used at multiple levels with minimal blood loss and a lower operative risk. Pedicle subtraction osteotomies provide nearly 3 times the per-level correction of Ponte/Smith-Petersen osteotomies but carry increased technical demands, longer operative time, and greater blood loss and associated morbidity. Vertebral column resections serve as the most powerful method, providing the most correction in the coronal and sagittal planes, but posing both the greatest technical challenge and the greatest risk to the patient in terms of possible neurological injury, operative time, and potential morbidity. The authors reviewed the literature relating to these osteotomy methods. They also provided case illustrations and suggestions for their proper application.

Immunogenomics of Hypermutated Glioblastoma: A Patient with Germline POLE Deficiency Treated with Checkpoint Blockade Immunotherapy

We present the case of a patient with a left frontal glioblastoma with primitive neuroectodermal tumor features and hypermutated genotype in the setting of a POLE germline alteration. During standard-of-care chemoradiation, the patient developed a cervical spine metastasis and was subsequently treated with pembrolizumab. Shortly thereafter, the patient developed an additional metastatic spinal lesion. Using whole-exome DNA sequencing and clonal analysis, we report changes in the subclonal architecture throughout treatment. Furthermore, a persistently high neoantigen load was observed within all tumors. Interestingly, following initiation of pembrolizumab, brisk lymphocyte infiltration was observed in the subsequently resected metastatic spinal lesion and an objective radiographic response was noted in a progressive intracranial lesion, suggestive of active central nervous system (CNS) immunosurveillance following checkpoint blockade therapy. SIGNIFICANCE It is unclear whether hypermutated glioblastomas are susceptible to checkpoint blockade in adults. Herein, we provide proof of principle that glioblastomas with DNA-repair defects treated with checkpoint blockade may result in CNS immune activation, leading to clinically and immunologically significant responses. These patients may represent a genomically stratified group for whom immunotherapy could be considered. Cancer Discov; 6(11); 1230-6. ©2016 AACR.See related commentary by Snyder and Wolchok, p. 1210This article is highlighted in the In This Issue feature, p. 1197.

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.

Blunt duodenal injuries in children

BACKGROUND Duodenal injury secondary to blunt trauma continues to pose a diagnostic challenge. The purpose of this study is to evaluate the cause, radiologic findings, and management of duodenal injuries from a Level I pediatric trauma center. METHODS A retrospective review of our trauma registry from 1990 to 2000 identified 24 children with blunt duodenal injuries. Clinical and radiographic findings and management strategies were assessed and compared in children with duodenal hematomas and perforations. RESULTS The majority of injuries were secondary to motor vehicle collisions. Pancreatic (42%) injuries were most commonly associated with duodenal trauma. With the exception of hematocrit level, initial clinical and laboratory findings were similar between groups. Of the 19 (79%) with duodenal hematomas, computed tomographic (CT) scan alone identified 15 and the remaining 4 were confirmed by duodenography. Incision and drainage of a hematoma was performed in two children. Duodenal perforation was identified in five (21%) children. Extraluminal air by CT scan was present in three of five children with perforation; however, none had extravasation of contrast. Four (80%) children with perforations underwent primary repair and one (20%) required segmental resection. CONCLUSION CT scanning remains a valuable tool in the diagnosis of blunt duodenal injuries in children. Although extravasation of oral contrast was not beneficial, the presence of extraluminal air was highly suggestive of perforation. The vast majority of hematomas were successfully managed nonoperatively, and duodenorrhaphy was safe and effective therapy for perforations.

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.

Histologic results 1 year after bioprosthetic repair of paraesophageal hernia in a canine model

BackgroundThe use of prosthetic materials for the repair of paraesophageal hiatal hernia (PEH) may lead to esophageal stricture and perforation. High recurrence rates after primary repair have led surgeons to explore other options, including various bioprostheses. However, the long-term effects of these newer materials when placed at the esophageal hiatus are unknown. This study assessed the anatomic and histologic characteristics 1 year after PEH repair using a U-shaped configuration of commercially available small intestinal submucosa (SIS) mesh in a canine model.MethodsSix dogs underwent laparoscopic PEH repair with SIS mesh 4 weeks after thoracoscopic creation of PEH. When the six dogs were sacrificed 12 months later, endoscopy and barium x-ray were performed, and biopsies of the esophagus and crura were obtained.ResultsThe mean weight of the dogs 1 year after surgery was identical to their entry weight. No dog had gross dysphagia, evidence of esophageal stricture, or reherniation. At sacrifice, the biomaterial was not identifiable grossly. Biopsies of the hiatal region showed fibrosis as well as muscle fiber proliferation and regeneration. No dog had erosion of the mesh into the esophagus.ConclusionsThis reproducible canine model of PEH formation and repair did not result in erosion of SIS mesh into the esophagus or in stricture formation. Native muscle ingrowth was noted 1 year after placement of the biomaterial. According to the findings, SIS may provide a scaffold for ingrowth of crural muscle and a durable repair of PEH over the long term.

Seven Years of Experience With C2 Translaminar Screw Fixation: Clinical Series and Review of the Literature

BACKGROUND:C2 translaminar screws offer biomechanical stability similar to that of other C2 fixation methods but with minimal risk to neural and vascular structures. OBJECTIVE:To report our experience with the technique since 2002 and to review the pertinent literature to advance the understanding of C2 translaminar screw fixation. METHODS:Fifty-two consecutive adult patients with disorders requiring axis stabilization were treated with C2 translaminar screws by a single surgeon. All patients underwent preoperative computed tomography scans to confirm the feasibility of screw placement. Patients were followed up with serial flexion/extension radiographs and/or computed tomography scans. RESULTS:The average age in our series was 58.1 years. One hundred three C2 translaminar screws were placed (average length, 28.9 mm). No vascular or neurological injuries occurred. Of 41 patients with sufficient follow-up (average, 13.3 months) to evaluate fusion, 1 instrumentation failure/pseudoarthrosis was observed. Five patients (average age, 78.7 years) died of complications related to medical comorbidities. In the literature, 169 cases of C2 translaminar fixation have been reported, with a fusion rate of 95.3% and no vertebral artery injuries. In biomechanical studies, C2 translaminar screws perform similarly to C2 pedicle screws and may outperform C2 pars screws in intact spine models. With disrupted atlantoaxial ligaments, constructs with C2 translaminar screws may not resist lateral bending as well as those with other screws, although they have more stability than uninstrumented, intact spines. CONCLUSION:This study reports 103 C2 translaminar screws, the largest single-surgeon series to date. C2 translaminar screws are a technically feasible, low-risk option for C2 fixation, with a 97.6% fusion rate in this series.

Clinical and radiographic outcomes after 3-column osteotomies with 5-year follow-up.

Study Design. Retrospective review of prospective database. Objective. To investigate long-term results after 3-column osteotomies (3-CO). Summary of Background Data. Short-term studies have noted improved outcomes and alignment after 3-CO, but there is a paucity of long-term studies with a large group of patients. Methods. An analysis of 126 patients who underwent a 3-CO (pedicle subtraction osteotomy [N = 101]/vertebral column resection [N = 25]) with minimum 5-year follow-up was performed at a single institution. The mean age was 48 years (range, 8–79 yr) and average follow-up was for 7 years (range, 5–14 yr). Oswestry Disability Index and Scoliosis Research Society (SRS) scores and radiographical parameters were assessed at baseline, 6 weeks, and 1, 2, 3, and/or 5 years postoperatively and complications were recorded. Results. Sagittal alignment improved at all postoperative time points from baseline (mean, 117 mm), but diminished from 6 weeks (mean, 24 mm) to 5 years (mean, 41 mm; P = 0.03). Average coronal alignment was improved from baseline (27 mm) at 6 weeks (18 mm; P = 0.003) and 5 years postoperatively (19 mm; P = 0.007), with no deterioration between 6 weeks and 5 years postoperatively (P = 0.9). Major surgical complications occurred in 36% (n = 45) and major repeat surgery was performed in 28% (n = 35). Significant improvements (P < 0.05) in Oswestry Disability Index and all SRS domain scores were found at each time point. All mean outcome scores at 5 years postoperatively exceeded minimal clinically important difference thresholds except the SRS function domain. Improvement in outcomes at 5 years postoperatively was similar in groups with major surgical complications versus those without and in those with reoperation versus those without. Conclusion. This study of 126 patients undergoing 3-CO found significant and sustained improvements in Oswestry Disability Index and SRS scores and sagittal alignment at a minimum 5 years postoperatively. This demonstrates the durability of these complex spinal reconstructions, even surprisingly in those patients having a major complication and/or revision surgery. Level of Evidence: 4

Extratemporal, nonlesional epilepsy in children: postsurgical clinical and neurocognitive outcomes

OBJECT Patients undergoing epilepsy surgery without evidence of a lesion on MR imaging and without a temporal source for seizure onset generally have less favorable outcomes than patients with structural lesions or temporal onset. However, many of these patients are viable candidates for invasive monitoring and subsequent resection or multiple subpial transections (MSTs). The purpose of this study was to evaluate the surgical treatment of pediatric patients with extratemporal, nonlesional epilepsy in order to better understand the clinical and neuropsychological outcomes expected in this patient group. METHODS Forty-three pediatric patients with negative results on MR imaging and lateralized, extratemporal findings on electroencephalography underwent invasive monitoring with grid and/or strip electrodes. Thirty-three subsequently had resection of an epileptogenic focus and/or MSTs. RESULTS Outcome was classified as Engel class I or II in 54.5% of the patients who underwent resection/MSTs and Engel class III or IV in 45.5%. Use of MSTs was associated with poor outcome. Neuropsychological evaluation showed significant improvement in immediate auditory attention following surgery and revealed several significant results on subgroup analysis. Complications occurred in 14% of patients (a 7% rate per procedure). Ten patients (23%) underwent invasive monitoring without proceeding to therapeutic surgery because no epileptogenic region was amenable to resection. Neuropsychological outcomes were generally stable. CONCLUSIONS Patients with extratemporal, nonlesional seizures are viable candidates for invasive monitoring with grid/strip electrodes, and good outcomes can be obtained with resective surgery. The use of MSTs may correlate with worse outcome. This study also provides additional data to assist in counseling patients on the risks of negative invasive monitoring, deficits resulting from resection/MSTs, and possible operative complications.

Radiographical and clinical outcomes of posterior column osteotomies in spinal deformity correction

Study Design. Prospectively enrolled, retrospectively analyzed case series. Objective. To evaluate a large series of pediatric patients/patients with adult spinal deformity undergoing surgery with posterior column osteotomies (PCOs). Summary of Background Data. Osteotomies of the posterior column (Smith-Petersen or Ponté) are used to reduce kyphosis, increase lordosis, or increase spinal flexibility. However, little focused evidence exists regarding the efficacy and safety of this technique. Methods. A total of 128 consecutive patients underwent posterior spinal fusion with PCOs with minimum 2-year follow-up. Seventy-five were primary surgical procedures; 53 were revisions. Data were collected from hospital charts, clinic notes, radiographs, and standardized questionnaires (Scoliosis Research Society-30 and Oswestry Disability Index). Results. A total of 128 patients aged 37.6 ± 21 years underwent 518 PCOs (mean, 4.0 ± 2.2 yr) with 14.4 ± 3 mean instrumentation levels, with 3-year (range, 2–6.8 yr) average follow-up. PCOs were used for kyphosis correction in 49%, scoliosis correction at the apex of a curve in 13%, and both in 38%. One hundred six patients had complete radiographical data available for evaluation. Mean kyphosis correction per PCO was 8.8° ± 7.2°, varying with patient age (10.2° for those younger than 21 yr vs. 7.7° for those 21 yr or older, P < 0.0001) and region of the spine: thoracolumbar (T10–L2) 11.6°, lumbar (L2–S1) 9.4°, midthoracic (T6–T10) 7.2° and proximal thoracic (T1–T6) 3.6°. With PCOs at the apex of a curve, the maximum coronal Cobb decreased from 66° ± 21° to 31° ± 14° (P < 0.0001). Average estimated blood loss was 1419 ± 887 mL, correlating with greater age (P < 0.0001) and more instrumented levels (P < 0.0001), but not with the number of PCOs (P = 0.32). Complications occurred in 31 (24.2%) patients, including 4 radiculopathies (none attributable to PCOs). Complications did not correlate with the number of PCOs (P = 0.5). Six (4.7%) patients had loss of spinal cord monitoring or a failed wake-up test that could be attributed to overcorrection with PCOs, but none had postoperative deficits. Oswestry Disability Index scores improved (34.4 ± 17 to 23.6 ± 18, P < 0.0001), as did normalized Scoliosis Research Society-30 scores (63.7 ± 13 to 76.4 ± 15, P < 0.0001). Conclusion. Patients in this series undergoing posterior spinal fusion with PCOs achieved overall favorable outcomes for spinal deformity correction. The number of PCOs did not correlate with increased estimated blood loss or complications. The main technical concern was overcorrection, but neurological consequences associated with overcorrection were identified by intraoperative spinal cord monitoring and wake-up tests, and no patients experienced permanent neurological deficits related to PCOs. Level of Evidence: 4