Object The object of this study was to evaluate an alternative surgical approach to degenerative thoracolumbar deformity in adults. The authors present their early experience with the minimally invasive, lateral retroperitoneal transpsoas approach for placing interbody grafts and providing anterior column support for adult degenerative deformity. Methods The authors retrospectively reviewed a prospectively acquired database of all patients with adult thoracolumbar degenerative deformity treated with the minimally invasive, lateral retroperitoneal transpsoas approach at our institution. All patient data were recorded including demographics, preoperative evaluation, procedure used, postoperative follow-up, operative time, blood loss, length of hospital stay, and complications. The Oswestry Disability Index and visual analog scale (for pain) were also administered pre- and postoperatively as early outcome measures. All patients were scheduled for follow-up postoperatively at weeks 2, 6, 12, and 24, and at 1 year. Results The authors identified 25 patients with adult degenerative deformity who were treated using the minimally invasive, lateral retroperitoneal transpsoas approach. All patients underwent discectomy and lateral interbody graft placement for anterior column support and interbody fusion. The mean total blood loss was 53 ml per level. The average length of stay in the hospital was 6.2 days. Mean follow-up was 11 months (range 3–20 months). A mean improvement of 5.7 points on visual analog scale scores and 23.7% on the Oswestry Disability Index was observed. Perioperative complications include 1 patient with rhabdomyolysis requiring temporary hemodialysis, 1 patient with subsidence, and 1 patient with hardware failure. Three patients (12%) experienced transient postoperative anterior thigh numbness, ipsilateral to the side of approach. In this series, 20 patients (80%) were identified who had more than 6 months of follow-up and radiographic evidence of fusion. The minimally invasive, lateral retroperitoneal transpsoas approach, without the use of osteotomies, did not correct the sagittal balance in approximately one-third of the patients. Conclusions Degenerative scoliosis of the adult spine is secondary to asymmetrical degeneration of the discs. Surgical decompression and correction of the deformity can be performed from an anterior, posterior, or combined approach. These procedures are often associated with long operative times and a high incidence of complications. The authors' experience with the minimally invasive, lateral retroperitoneal transpsoas approach for placement of a large interbody graft for anterior column support, restoration of disc height, arthrodesis, and realignment is a feasible alternative to these procedures.

The use of wider intervertebral cages leads to a significantly lower rate of subsidence, but a longer cage does not necessarily offer a similar advantage. Wide cages are protective against subsidence, and the widest cages should be used whenever feasible for interbody fusion in the lumbar spine to protect indirect compression and promote arthrodesis.

ObjectThe lateral retroperitoneal transpsoas approach is being increasingly employed to treat various spinal disorders. The minimally invasive blunt retroperitoneal and transpsoas dissection poses a risk of injury to major nervous structures. The addition of electrophysiological monitoring potentially decreases the risk of injury to the lumbar plexus. With respect to the use of the direct transpsoas approach, however, there is sparse knowledge regarding the relationship between the retroperitoneum/psoas muscle and the lumbar plexus at each lumbar segment. The authors undertook this anatomical cadaveric dissection study to define the anatomical safe zones relative to the disc spaces for prevention of nerve injuries during the lateral retroperitoneal transpsoas approach.MethodsTwenty lumbar segments were dissected and studied. The relationship between the retroperitoneum, psoas muscle, and the lumbar plexus was analyzed. The area between the anterior and posterior edges of the vertebral body (VB) was divided into 4 equal zones. Radiopaque markers were placed in each disc space at the midpoint of Zone III (middle posterior quarter). At each segment, the psoas muscle, lumbar plexus, and nerve roots were dissected. The distribution of the lumbar plexus with reference to the markers at each lumbar segment was analyzed.ResultsAll parts of the lumbar plexus, including nerve roots, were found within the substance of the psoas muscle dorsal to the posterior fourth of the VB (Zone IV). No Zone III marker was posterior to any part of the lumbar plexus with the exception of the genitofemoral nerve. The genitofemoral nerve travels obliquely in the substance of the psoas muscle from its origin to its innervations. It emerges superficially and anterior from the medial border of the psoas at the L3–4 level and courses along the anterior medial fourth of the L-4 and L-5 VBs (Zone I). The nerves of the plexus that originate at the upper lumbar segments emerge from the lateral border of the psoas major and cross obliquely into the retroperitoneum in front of the quadratus lumborum and the iliacus muscles to the iliac crest.ConclusionsWith respect to prevention of direct nerve injury, the safe anatomical zones at the disc spaces from L1–2 to L3–4 are at the middle posterior quarter of the VB (midpoint of Zone III) and the safe anatomical zone at the L4–5 disc space is at the midpoint of the VB (Zone II–Zone III demarcation). There is risk of direct injury to the genitofemoral nerve in Zone II at the L2–3 space and in Zone I at the lower lumbar levels L3–4 and L4–5. There is also a potential risk of injury to the ilioinguinal, iliohypogastric, and lateral femoral cutaneous nerves in the retroperitoneal space where they travel obliquely, inferiorly, and anteriorly to the reach the iliac crest and the abdominal wall.

Pharmacotherapy and behavioral treatments for alcohol use disorder are limited in their effectiveness, and new treatments with innovative mechanisms would be valuable. In this pilot study, the authors tested whether a single subanesthetic infusion of ketamine administered to adults with alcohol dependence and engaged in motivational enhancement therapy affects drinking outcomes.Methods: Participants were randomly assigned to a 52minute intravenous administration of ketamine (0.71 mg/kg, N=17) or the active control midazolam (0.025 mg/kg, N=23), provided during the second week of a 5-week outpatient regimen of motivational enhancement therapy. Alcohol use following the infusion was assessed with timeline followback method, with abstinence confirmed by urine ethyl glucuronide testing. A longitudinal logistic mixed-effects model was used to model daily abstinence from alcohol over the 21 days after ketamine infusion.

Background Cocaine dependence involves problematic neuroadaptations that may be responsive to modulation of glutamatergic circuits. This investigation examined the effects of sub-anesthetic ketamine infusions on motivation for quitting cocaine and on cue-induced craving in cocaine dependent participants, 24 hours post-infusion. Methods Eight volunteers with active DSM-IV cocaine dependence not seeking treatment or abstinence were entered into this crossover, double-blind trial. Three 52 minute intravenous infusions were administered: ketamine (0.41 mg/kg or 0.71 mg/kg) or lorazepam 2 mg, counterbalanced into three orderings in which ketamine 0.41 mg/kg always preceded the 0.71 mg/kg dose. Infusions were separated by 48 hours, and assessments occurred at baseline and at 24 hours post-infusion. Outcomes were change between post-infusion and pre-infusion values for 1) motivation to quit cocaine scores using the University of Rhode Island Change Assessment (URICA), and 2) sums of visual analogue scale (VAS) craving ratings administered during cue exposure. Results Compared to the active control lorazepam, a single ketamine infusion (0.41 mg/kg) led to a mean 3.9 points gain in URICA (p=0.012), which corresponds to an approximately 60% increase over preceding values. There was a reduction of comparable magnitude in cue-induced craving (p=0.012). A subsequent ketamine infusion (0.71 mg/kg) led to further reductions in cue-induced craving compared to the control. Infusions were well tolerated. Conclusions Sub-anesthetic ketamine demonstrated promising effects on motivation to quit cocaine and on cue-induced craving, 24 hours post-infusion. Research is needed to expand on these preliminary results, and to evaluate the efficacy of this intervention in clinical settings.

Research has suggested that subanesthetic doses of ketamine may work to improve cocaine-related vulnerabilities and facilitate efforts at behavioral modification. The purpose of this trial was to test whether a single ketamine infusion improved treatment outcomes in cocaine-dependent adults engaged in mindfulness-based relapse prevention.Methods: Fifty-five cocaine-dependent individuals were randomly assigned to receive a 40-minute intravenous infusion of ketamine (0.5 mg/kg) or midazolam (the control condition) during a 5-day inpatient stay, during which they also initiated a 5-week course of mindfulness-based relapse prevention. Cocaine use was assessed through self-report and urine toxicology. The primary outcomes were end-ofstudy abstinence and time to relapse (defined as first use or dropout).Results: Overall, 48.2% of individuals in the ketamine group maintained abstinence over the last 2 weeks of the trial, compared with 10.7% in the midazolam group (intent-totreat analysis). The ketamine group was 53% less likely (hazard ratio=0.47; 95% CI=0.24, 0.92) to relapse (dropout or use cocaine) compared with the midazolam group, and craving scores were 58.1% lower in the ketamine group throughout the trial (95% CI=18.6, 78.6); both differences were statistically significant. Infusions were well tolerated, and no participants were removed from the study as a result of adverse events.

Object Symptomatic herniated thoracic discs remain a surgical challenge and historically have been associated with significant complications. While neurological outcomes have improved with the abandonment of decompressive laminectomy, the attempt to minimize surgical complications and associated morbidities continues through less invasive approaches. Many of these techniques, such as thoracoscopy, have not been widely adopted due to technical difficulties. The current study was performed to examine the safety and early results of a minimally invasive lateral approach for symptomatic thoracic herniated intervertebral discs. Methods Sixty patients from 5 institutions were treated using a mini-open lateral approach for 75 symptomatic thoracic herniated discs with or without calcification. The mean age was 57.9 years (range 23–80 years), and 53.3% of the patients were male. Treatment levels ranged from T4–5 to T11–12, with 1–3 levels being treated (mean 1.3 levels). The most common levels treated were T11–12 (14 cases [18.7%]), T7–8 (12 cases [16%]), and T8–9 (12 cases [16%]). Symptoms included myelopathy in 70% of cases, radiculopathy in 51.7%, axial back pain in 76.7%, and bladder and/or bowel dysfunction in 26.7%. Instrumentation included an interbody spacer in all but 6 cases (10%). Supplemental internal fixation included anterolateral plating in 33.3% of cases and pedicle screws in 10%; there was no supplemental internal fixation in 56.7% of cases. Follow-up ranged from 0.5 to 24 months (mean 11.0 months). Results The median operating time, estimated blood loss, and length of stay were 182 minutes, 290 ml, and 5.0 days, respectively. Four major complications occurred (6.7%): pneumonia in 1 patient (1.7%); extrapleural free air in 1 patient (1.7%), treated with chest tube placement; new lower-extremity weakness in 1 patient (1.7%); and wound infection in posterior instrumentation in 1 patient (1.7%). Reoperations occurred in 3 cases (5%): one for posterior reexploration, one for infection in posterior instrumentation, and one for removal of symptomatic residual disc material. Back pain, measured using the visual analog scale, improved 60% from the preoperative score to the last follow-up, that is, from 7.8 to 3.1. Excellent or good overall outcomes were achieved in 80% of the patients, a fair or unchanged outcome resulted in 15%, and a poor outcome occurred in 5%. Moreover, myelopathy, radiculopathy, axial back pain, and bladder and/or bowel dysfunction improved in 83.3%, 87.0%, 91.1%, and 87.5% of cases, respectively. Conclusions The authors' early experience with a large multicenter series suggested that the minimally invasive lateral approach is a safe, reproducible, and efficacious procedure for achieving adequate decompression in thoracic disc herniations in a less invasive manner than conventional surgical techniques and without the use of endoscopes. Symptom resolution was achieved at similar rates using this approach as compared with the most efficacious techniques in the literature, and with fewer complications in most circumstances.

Repeated drug consumption may progress to problematic use by triggering neuroplastic adaptations that attenuate sensitivity to natural rewards while increasing reactivity to craving and drug cues. Using an established laboratory model aimed at evaluating behavioral shifts in the salience of cocaine now vs. money later, we evaluated the effect on cocaine use of a single sub-anesthetic dose of the N-methyl-D-aspartate receptor antagonist ketamine, which converging evidence suggests may work to correct problematic neuroadaptations and restore motivation for non-drug rewards. We found that ketamine, as compared to the control, significantly decreased cocaine self-administration by 67% relative to baseline at greater than 24 hours post-infusion, the most robust reduction observed to date in human cocaine users and the first to involve mechanisms other than stimulant or dopamine agonist effects. These findings signal new directions in medication development for substance use disorders.