Surgical complications in adult spondylolisthesis
Michael G. Fehlings and Doron Rabin
Randall Schultz Jr., Andrew Steven, Aaron Wessell, Nancy Fischbein, Charles A. Sansur, Dheeraj Gandhi, David Ibrahimi and Prashant Raghavan
Dorsal arachnoid webs (DAWs) and spinal cord herniation (SCH) are uncommon abnormalities affecting the thoracic spinal cord that can result in syringomyelia and significant neurological morbidity if left untreated. Differentiating these 2 entities on the basis of clinical presentation and radiological findings remains challenging but is of vital importance in planning a surgical approach. The authors examined the differences between DAWs and idiopathic SCH on MRI and CT myelography to improve diagnostic confidence prior to surgery.
Review of the picture archiving and communication system (PACS) database between 2005 and 2015 identified 6 patients with DAW and 5 with SCH. Clinical data including demographic information, presenting symptoms and neurological signs, and surgical reports were collected from the electronic medical records. Ten of the 11 patients underwent MRI. CT myelography was performed in 3 patients with DAW and in 1 patient with SCH. Imaging studies were analyzed by 2 board-certified neuroradiologists for the following features: 1) location of the deformity; 2) presence or absence of cord signal abnormality or syringomyelia; 3) visible arachnoid web; 4) presence of a dural defect; 5) nature of dorsal cord indentation (abrupt “scalpel sign” vs “C”-shaped); 6) focal ventral cord kink; 7) presence of the nuclear trail sign (endplate irregularity, sclerosis, and/or disc-space calcification that could suggest a migratory path of a herniated disc); and 8) visualization of a complete plane of CSF ventral to the deformity.
The scalpel sign was positive in all patients with DAW. The dorsal indentation was C-shaped in 5 of 6 patients with SCH. The ventral subarachnoid space was preserved in all patients with DAW and interrupted in cases of SCH. In no patient was a web or a dural defect identified.
DAW and SCH can be reliably distinguished on imaging by scrutinizing the nature of the dorsal indentation and the integrity of the ventral subarachnoid space at the level of the cord deformity.
Christopher M. Maulucci, Charles A. Sansur, Vaneet Singh, Alexandra Cholewczynski, Snehal S. Shetye, Kirk McGilvray and Christian M. Puttlitz
Nerve root decompression to relieve pain and radiculopathy remains one of the main goals of fusion-promoting procedures in the subaxial cervical spine. The use of allograft facet spacers has been suggested as a potential alternative for performing foraminotomies to increase the space available for the cervical nerve roots while providing segmental stiffening. Therefore, the goal of this cadaveric biomechanical study was to determine the acute changes in kinetics and foraminal area after the insertion of cortical bone facet spacers into the subaxial cervical spine.
Allograft spacers (2 mm in height) were placed bilaterally into cadaveric cervical spine specimens (C2-T1, age of donors 57.5 ± 9.5 years, n = 7) at 1 (C4–5) and 3 (C3–6) levels with and without laminectomies and posterior lateral mass screw fixation. Standard stereophotogrammetry under pure moment loading was used to assess spinal kinetics. In addition, the authors performed 3D principal component analysis of CT scans to determine changes in foraminal cross-sectional area (FCSA) available for the spinal nerve roots.
Generally, the introduction of 2-mm-height facet spacers to the cervical spine produced mild, statistically insignificant reductions in motion with particular exceptions at the levels of implantation. No significant adjacent-level motion effects in any bending plane were observed. The addition of the posterior instrumentation (PI) to the intact spines resulted in statistically significant reductions in motion at all cervical levels and bending planes. The same kinetic results were obtained when PI was added to spines that also had facet spacers at 3 levels and spines that had been destabilized by en bloc laminectomy. The addition of 2-mm facet spacers at C3–4, C4–5, and C5–6 did produce statistically significant increases in FCSA at those levels.
The addition of allograft cervical facet spacers should be considered a potential option to accomplish indirect foraminal decompression as measured in this cadaveric biomechanical study. However, 2-mm spacers without supplemental instrumentation do not provide significantly increased spinal segmental stability.
Charles A. Sansur, Robert C. Frysinger, Nader Pouratian, Kai-Ming Fu, Markus Bittl, Rod J. Oskouian, Edward R. Laws and W. Jeffrey Elias
Intracranial hemorrhage (ICH) is the most significant complication associated with the placement of stereotactic intracerebral electrodes. Previous reports have suggested that hypertension and the use of microelectrode recording (MER) are risk factors for cerebral hemorrhage. The authors evaluated the incidence of symptomatic ICH in a large cohort of patients with various diseases treated with stereotactic electrode placement. They examined the effect of comorbidities on the risk of ICH and independently assessed the risks associated with age, sex, use of MER, diagnosis, target location, hypertension, and previous use of anticoagulant medications. The authors also evaluated the effect of hemorrhage on length of hospital stay and discharge disposition.
Between 1991 and 2005, 567 electrodes were placed by two neurosurgeons during 337 procedures in 259 patients. Deep brain stimulation (DBS) was performed in 167 procedures, radiofrequency lesioning (RFL) of subcortical structures in 74, and depth electrodes were used in 96 procedures in patients with epilepsy. Electrodes were grouped according to target, patient diagnosis, use of MER, patient history of hypertension, and patient prior use of anticoagulant medication (stopped 10 days before surgery). The Charlson Comorbidity Index (CCI) was used to evaluate the effect of comorbidities. The CCI score, patient age, length of hospital stay, and discharge status were continuous variables. Symptomatic hemorrhages were grouped as transient or leading to permanent neurological deficits.
The risk of hemorrhage leading to permanent neurological deficits in this study was 0.7%, and the risk of symptomatic hemorrhage was 1.2%. A patient history of hypertension was the most significant factor associated with hemorrhage (p = 0.007). Older age, male sex, and a diagnosis of Parkinson disease (PD) were also significantly associated with hemorrhage (p = 0.01, 0.04, 0.007, respectively). High CCI scores, specific target locations, and prior use of anticoagulant therapy were not associated with an increased risk of hemorrhage. The use of MER was not found to be correlated with an increased hemorrhage rate (p = 0.34); however, the number of hemorrhages in the patients who underwent DBS was insufficient to draw definitive conclusions. The mean length of stay for the DBS, RFL, and depth electrode patient groups was 2.9, 2.6, and 11.0 days, respectively. For patients who received DBS and RFL, the mean duration of hospitalization in cases of symptomatic hemorrhage was 8.2 days compared with 2.7 days in those without hemorrhaging (p < 0.0001). Three of the seven patients with symptomatic hemorrhages were discharged home.
The placement of stereotactic electrodes is generally safe, with a symptomatic hemorrhage rate of 1.2%, and a 0.7% rate of permanent neurological deficit. Consistent with prior reports, this study confirms that hypertension is a significant risk factor for hemorrhage. Age, male sex, and diagnosis of PD were also significant risk factors. Patients with symptomatic hemorrhage had longer hospital stays and were less likely to be discharged home.
John D. Heiss, Kendall Snyder, Matthew M. Peterson, Nicholas J. Patronas, John A. Butman, René K. Smith, Hetty L. DeVroom, Charles A. Sansur, Eric Eskioglu, William A. Kammerer and Edward H. Oldfield
The pathogenesis of syringomyelia in patients with an associated spinal lesion is incompletely understood. The authors hypothesized that in primary spinal syringomyelia, a subarachnoid block effectively shortens the length of the spinal subarachnoid space (SAS), reducing compliance and the ability of the spinal theca to dampen the subarachnoid CSF pressure waves produced by brain expansion during cardiac systole. This creates exaggerated spinal subarachnoid pressure waves during every heartbeat that act on the spinal cord above the block to drive CSF into the spinal cord and create a syrinx. After a syrinx is formed, enlarged subarachnoid pressure waves compress the external surface of the spinal cord, propel the syrinx fluid, and promote syrinx progression.
To elucidate the pathophysiology, the authors prospectively studied 36 adult patients with spinal lesions obstructing the spinal SAS. Testing before surgery included clinical examination; evaluation of anatomy on T1-weighted MRI; measurement of lumbar and cervical subarachnoid mean and pulse pressures at rest, during Valsalva maneuver, during jugular compression, and after removal of CSF (CSF compliance measurement); and evaluation with CT myelography. During surgery, pressure measurements from the SAS above the level of the lesion and the lumbar intrathecal space below the lesion were obtained, and cardiac-gated ultrasonography was performed. One week after surgery, CT myelography was repeated. Three months after surgery, clinical examination, T1-weighted MRI, and CSF pressure recordings (cervical and lumbar) were repeated. Clinical examination and MRI studies were repeated annually thereafter. Findings in patients were compared with those obtained in a group of 18 healthy individuals who had already undergone T1-weighted MRI, cine MRI, and cervical and lumbar subarachnoid pressure testing.
In syringomyelia patients compared with healthy volunteers, cervical subarachnoid pulse pressure was increased (2.7 ± 1.2 vs 1.6 ± 0.6 mm Hg, respectively; p = 0.004), pressure transmission to the thecal sac below the block was reduced, and spinal CSF compliance was decreased. Intraoperative ultrasonography confirmed that pulse pressure waves compressed the outer surface of the spinal cord superior to regions of obstruction of the subarachnoid space.
These findings are consistent with the theory that a spinal subarachnoid block increases spinal subarachnoid pulse pressure above the block, producing a pressure differential across the obstructed segment of the SAS, which results in syrinx formation and progression. These findings are similar to the results of the authors' previous studies that examined the pathophysiology of syringomyelia associated with obstruction of the SAS at the foramen magnum in the Chiari Type I malformation and indicate that a common mechanism, rather than different, separate mechanisms, underlies syrinx formation in these two entities. Clinical trial registration no.: NCT00011245.
Charles A. Sansur, Nicholas M. Caffes, David M. Ibrahimi, Nathan L. Pratt, Evan M. Lewis, Ashley A. Murgatroyd and Bryan W. Cunningham
Optimal strategies for fixation in the osteoporotic lumbar spine remain a clinical issue. Classic transpedicular fixation in the osteoporotic spine is frequently plagued with construct instability, often due to inadequate cortical screw–bone purchase. A cortical bone trajectory maximizes bony purchase and has been reported to provide increased screw pullout strength. The aim of the current investigation was to evaluate the biomechanical efficacy of cortical spinal fixation as a surgical alternative to transpedicular fixation in the osteoporotic lumbar spine under physiological loading.
Eight fresh-frozen human spinopelvic specimens with low mean bone mineral densities (T score less than or equal to –2.5) underwent initial destabilization, consisting of laminectomy and bilateral facetectomies (L2–3 and L4–5), followed by pedicle or cortical reconstructions randomized between levels. The surgical constructs then underwent fatigue testing followed by tensile load to failure pullout testing to quantify screw pullout force.
When stratifying the pullout data with fixation technique and operative vertebral level, cortical screw fixation exhibited a marked increase in mean load at failure in the lower vertebral segments (p = 0.188, 625.6 ± 233.4 N vs 450.7 ± 204.3 N at L-4 and p = 0.219, 640.9 ± 207.4 N vs 519.3 ± 132.1 N at L-5) while transpedicular screw fixation demonstrated higher failure loads in the superior vertebral elements (p = 0.024, 783.0 ± 516.1 N vs 338.4 ± 168.2 N at L-2 and p = 0.220, 723.0 ± 492.9 N vs 469.8 ± 252.0 N at L-3). Although smaller in diameter and length, cortical fixation resulted in failures that were not significantly different from larger pedicle screws (p > 0.05, 449.4 ± 265.3 N and 541.2 ± 135.1 N vs 616.0 ± 384.5 N and 484.0 ± 137.1 N, respectively).
Cortical screw fixation exhibits a marked increase in mean load at failure in the lower vertebral segments and may offer a viable alternative to traditional pedicle screw fixation, particularly for stabilization of lower lumbar vertebral elements with definitive osteoporosis.
Adam S. Kanter, Alfa O. Diallo, John A. Jane Jr., Jason P. Sheehan, Ashok R. Asthagiri, Rod J. Oskouian, David O. Okonkwo, Charles A. Sansur, Mary Lee Vance, Alan D. Rogol and EdwardR. Laws Jr
Despite ongoing advances in surgical and radiotherapeutic techniques, pediatric Cushing's disease remains a diagnostic and therapeutic challenge. The authors report on the results of a single-center retrospective review of 33 pediatric patients with Cushing's disease, providing details with respect to clinical presentation, diagnostic evaluation, therapeutic course, complications, and outcomes.
There were 17 female and 16 male patients whose mean age was 13 years (range 5–19 years) in whom a diagnosis of Cushing's disease was based on clinical and biochemical criteria. Typical symptoms included weight gain (91%), prepubertal growth delay (83%), round facies (61%), hirsutism (58%), headache (45%), abdominal striae (42%), acne (33%), amenorrhea (24%), and hypertension (24%). In 67% of the cases, preoperative magnetic resonance images revealed a pituitary lesion and in 82% of the cases the imaging studies effectively predicted lateralization. Inferior petrosal sinus sampling was performed in seven patients (21%), and in all of these cases lateralization was 100% reliable. Fifty-five percent underwent selective adenomectomies and 45% underwent subtotal hypophysectomies.
Complications included one case of diabetes insipidus, one of persistent hypocortisolemia necessitating prolonged glucocorticoid replacement therapy, and one minor vascular injury that did not necessitate postoperative management modification or cause sequelae. There were no surgery-related deaths and no cases of postoperative cerebrospinal fluid leakage or meningitis. During a mean follow-up period of 44 months, clinical remission was ultimately achieved in 91% of patients: 76% after transsphenoidal surgery alone and an additional 15% after adjuvant radiosurgery and/or adrenalectomy following surgical failure. Three patients (12%) experienced disease recurrence and underwent a second surgical procedure at 18, 81, and 92 months, respectively; based on clinical and biochemical criteria a second remission was achieved in all. Three patients (9%) remain with persistent disease.
Pediatric Cushing's disease is a rare condition, often requiring a multidisciplinary diagnostic and a multimodal therapeutic approach for successful long-term remission.
Jay Jagannathan, Ekawut Chankaew, Peter Urban, Aaron S. Dumont, Charles A. Sansur, John Kern, Benjamin Peeler, W. Jeffrey Elias, Francis Shen, Mark E. Shaffrey, Richard Whitehill, Vincent Arlet and Christopher I. Shaffrey
In this paper, the authors review the functional and cosmetic outcomes and complications in 300 patients who underwent treatment for lumbar spine disease via either an anterior paramedian or conventional anterolateral retroperitoneal approach.
Seven surgeons performed anterior lumbar surgeries in 300 patients between August 2004 and December 2006. One hundred and eighty patients were treated with an anterior paramedian approach, and 120 patients with an anterolateral retroperitoneal approach. An access surgeon was used in 220 cases (74%). Postoperative evaluation in all patients consisted of clinic visits, assessment with the modified Scoliosis Research Society–30 instrument, as well as a specific questionnaire relating to wound appearance and patient satisfaction with the wound.
At a mean follow-up of 31 months (range 12–47 months), the mean Scoliosis Research Society–30 score (out of 25) was 21.2 in the patients who had undergone the anterior paramedian approach and 19.4 in those who had undergone the anterolateral retroperitoneal approach (p = 0.005). The largest differences in quality of life measures were observed in the areas of pain control (p = 0.001), self-image (p = 0.004), and functional activity (p = 0.003), with the anterior paramedian group having higher scores in all 3 categories. Abdominal bulging in the vicinity of the surgical site was the most common wound complication observed and was reported by 22 patients in the anterolateral retroperitoneal group (18%), and 2 patients (1.1%) in the anterior paramedian group. Exposures of ≥ 3 levels with the anterolateral approach were associated with abdominal bulging (p = 0.04), while 1- or 2-level exposures were not (p > 0.05). Overall satisfaction with incisional appearance was higher in patients with an anterior paramedian incision (p = 0.001) and with approaches performed by an access surgeon (p = 0.004).
Patients who undergo an anterior paramedian approach to the lumbar spine have a higher quality of life and better cosmetic outcomes than patients undergoing an anterolateral retroperitoneal approach.
Rod J. Oskouian Jr., Christopher I. Shaffrey, Richard Whitehill, Charles A. Sansur, Nader Pouratian, Adam S. Kanter, Ashok R. Asthagiri, Aaron S. Dumont, Jason P. Sheehan, W. Jeffrey Elias and Mark E. Shaffrey
The purpose of this study was to evaluate the results obtained in patients who underwent anterior stabilization for three-column thoracolumbar fractures.
The authors retrospectively reviewed available clinical and radiographic data (1997–2006) to classify three-column thoracolumbar fractures according to the Association for the Study of Internal Fixation (AO) system, neurological status, spinal canal compromise, pre- and postoperative segmental angulation, and arthrodesis rate.
The mean computed tomography–measured preoperative spinal canal compromise was 48.3% (range 8–92%), and the mean vertebral body height loss was 39.4%. The mean preoperative kyphotic deformity of 14.9° improved to 4.6° at the final follow-up examination. Although this angulation had increased a mean of 1.8° during the follow-up period, the extent of correction was still significant compared with the preoperative angulation (p < 0.01). There were no cases of vascular complication or neurological deterioration.
Contemporary anterior spinal reconstruction techniques can allow certain types of unstable three-column thoracolumbar fractures to be treated via an anterior approach alone. Compared with traditional posterior approaches, the anterior route spares lumbar motion segments and obviates the need for harvesting of the iliac crest.
Presented at the 2009 Joint Spine Section Meeting
Charles A. Sansur, Davis L. Reames, Justin S. Smith, D. Kojo Hamilton, Sigurd H. Berven, Paul A. Broadstone, Theodore J. Choma, Michael James Goytan, Hilali H. Noordeen, Dennis Raymond Knapp Jr., Robert A. Hart, Reinhard D. Zeller, William F. Donaldson III, David W. Polly Jr., Joseph H. Perra, Oheneba Boachie-Adjei and Christopher I. Shaffrey
This is a retrospective review of 10,242 adults with degenerative spondylolisthesis (DS) and isthmic spondylolisthesis (IS) from the morbidity and mortality (M&M) index of the Scoliosis Research Society (SRS). This database was reviewed to assess complication incidence, and to identify factors that were associated with increased complication rates.
The SRS M&M database was queried to identify cases of DS and IS treated between 2004 and 2007. Complications were identified and analyzed based on age, surgical approach, spondylolisthesis type/grade, and history of previous surgery. Age was stratified into 2 categories: > 65 years and ≤ 65 years. Surgical approach was stratified into the following categories: decompression without fusion, anterior, anterior/posterior, posterior without instrumentation, posterior with instrumentation, and interbody fusion. Spondylolisthesis grades were divided into low-grade (Meyerding I and II) versus high-grade (Meyerding III, IV, and V) groups. Both univariate and multivariate analyses were performed.
In the 10,242 cases of DS and IS reported, there were 945 complications (9.2%) in 813 patients (7.9%). The most common complications were dural tears, wound infections, implant complications, and neurological complications (range 0.7%–2.1%). The mortality rate was 0.1%. Diagnosis of DS had a significantly higher complication rate (8.5%) when compared with IS (6.6%; p = 0.002). High-grade spondylolisthesis correlated strongly with a higher complication rate (22.9% vs 8.3%, p < 0.0001). Age > 65 years was associated with a significantly higher complication rate (p = 0.02). History of previous surgery and surgical approach were not significantly associated with higher complication rates. On multivariate analysis, only the grade of spondylolisthesis (low vs high) was in the final best-fit model of factors associated with the occurrence of complications (p < 0.0001).
The rate of total complications for treatment of DS and IS in this series was 9.2%. The total percentage of patients with complications was 7.9%. On univariate analysis, the complication rate was significantly higher in patients with high-grade spondylolisthesis, a diagnosis of DS, and in older patients. Surgical approach and history of previous surgery were not significantly correlated with increased complication rates. On multivariate analysis, only the grade of spondylolisthesis was significantly associated with the occurrence of complications.