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What’s New in Spine Surgery 2020

Every month, JBJS publishes a review of the most pertinent and impactful studies published in the orthopaedic literature during the previous year in 13 subspecialties. Click here for a collection of OrthoBuzz summaries of these “What’s New” articles. This month, co-author Jacob M. Buchowski, MD, selected the 5 most clinically compelling findings from the >30 studies summarized in the June 17, 2020 “What’s New in Spine Surgery.

Adult Spinal Deformity
A recent randomized controlled trial compared operative vs nonoperative treatment among 63 adult patients with symptomatic lumbar scoliosis. An additional 223 patients were included in an observational arm of the study. At 2 years, 64% of the randomized patients in the nonoperative group had crossed over to the operative group. In an as-treated analysis, surgery was associated with superior improvement, but the high crossover rate precludes making firm comparative conclusions.

Spinal Cord Injuries
—A small study of 3 subjects1 who had sustained a spinal cord injury investigated the delivery of spatially selective stimulation to posterior nerve roots innervating the lumbosacral spinal cord through an implantable pulse generator with real-time triggering capability. This method reestablished adaptive control over previously paralyzed muscles, and subjects were eventually able to walk or bike during spatiotemporal stimulation.

Cervical Myelopathy
—A prospective study of >700 patients with degenerative cervical myelopathy2 examined the impact of surgical management on neck pain outcomes. Using the Neck Disability Index at baseline and at 6, 12, and 24 months postoperatively, researchers found significant improvement in functional and pain scores that met or exceeded the minimum clinically important difference at all follow-up time points.

Lumbar Stenosis
—A retrospective study of >1,800 patients with symptomatic lumbar stenosis3 investigated whether pain improvements could be obtained surgically with decompression alone without fusion. At 1 year after surgery, decompression alone was associated with significant improvement in all patient-reported outcomes, suggesting that a concomitant fusion may not be required in such cases.

Opioid Consumption
—A retrospective study of nearly 29,000 patients4 examined the effects of chronic preoperative opioid therapy on medium- and long-term outcomes after lumbar arthrodesis surgery. Postoperatively, chronic opioid use prior to surgery was associated with an increased risk of 90-day emergency department visits and prolonged 1- and 2-year narcotic use.

References

  1. Wagner FB, Mignardot JB, Le Goff-Mignardot CG, Demesmaeker R, Komi S, Capogrosso M, Rowald A, Se´añez I, Caban M, Pirondini E, Vat M, McCracken LA, Heimgartner R, Fodor I, Watrin A, Seguin P, Paoles E, Van Den Keybus K, Eberle G, Schurch B, Pralong E, Becce F, Prior J, Buse N, Buschman R, Neufeld E, Kuster N, Carda S, von Zitzewitz J, Delattre V, Denison T, Lambert H, Minassian K, Bloch J. Courtine G. Targeted neurotechnology restores walking in humans with spinal cord injury. Nature. 2018 Nov;563(7729):65-71. Epub 2018 Oct 31.
  1. Schneider MM, Tetreault L, Badhiwala JH, Zhu MP, Wilson J, Fehlings MG. 42. The impact of surgical decompression on neck pain outcomes in patients with degenerative cervical myelopathy: results from the multicenter prospective AOSpine studies. Spine J. 2019 Sep;19(9):S21.
  2. Bech-Azeddine R, Fruensgaard S, Andersen M, Carreon LY. 215. Outcomes of decompression without fusion in patients with lumbar spinal stenosis with back pain. Spine J. 2019 Sep;19(9):S106.
  3. Eisenberg JM, Kalakoti P, Hendrickson NR, Saifi C, Pugely AJ. 142. Impact of preoperative chronic opioid therapy on long-term outcomes, reoperations, complications and resource utilization after lumbar arthrodesis. Spine J. 2019 Sep; 19(9):S68-9.

Is the Tethering Juice Worth the Squeeze in AIS?

The tried-and-true treatment for progressive adolescent idiopathic scoliosis (AIS) is a posterior spinal fusion (PSF). However, for skeletally immature patients, there is increasing interest in motion-sparing growth modulation, specifically anterior vertebral body tethering (AVBT). Early reports on tethering looked promising, but the long-term prognosis remains fuzzy.

Newton et al. clarify this somewhat in the May 6, 2020 issue of JBJS. They retrospectively compared outcomes among a cohort of 23 AVBT patients followed for a mean of 3.4 years with those among a matched cohort of 26 PSF patients followed for a mean of 3.6 years. The groups were well-matched in terms of demographics and preoperative curve measurements, but the AVBT group was slightly less skeletally mature based on triradiate cartilage status and Sanders classification.

The authors found that both groups experienced significant postoperative curve correction, but the PSF group had significantly greater immediate correction of the main thoracic curve (78%) than the AVBT group (36%). Smaller immediate correction is to be expected in a growth-modulation procedure, which allows the spine to “grow straighter” over time with the tether. But at the final follow-up, the AVBT group had only a 43% curve correction versus 69% final follow-up correction in the PSF group. In addition, 9 revision procedures occurred in the AVBT group, versus none in the PSF group. Twelve patients (52%) in the AVBT group had evidence of broken tethers, with 3 of those patients undergoing revision surgery due to curve progression linked to tether breakage.

Overall, 12 of 23 patients in the AVBT group (52%) were deemed a “clinical success” at the end of the study (defined as a thoracic curve <35° without a need for a secondary fusion) while all 26 patients in the PSF group were deemed a clinical success. Anterior vertebral body tethering may have a role in the treatment of scoliosis in the growing spine, but the results to date, including these from Newton et al., lead me to question whether the tethering “juice” in its current form is worth the “squeeze.”

Matthew R. Schmitz, MD
JBJS Deputy Editor for Social Media

Spine Surgery in Singapore Amid COVID-19

JBJS’s first COVID-19 article was about the experiences of orthopaedic surgeons in Singapore. The latest one also comes from authors in Singapore. Soh et al. focus on the impact the pandemic has had on spine surgery in that country. The authors emphasize the need to constantly review and adapt policies amid the moving target that the COVID-19 pandemic represents.

Here’s what the spine service at Soh et al.’s institution (a tertiary hospital and major trauma center) did during the first 6 weeks of the outbreak, which began in Singapore in January:

  • Reduced elective spine surgeries by 50%, cancelling all spinal-deformity or revision cases and prioritizing minimally invasive and endoscopic cases that required a shorter length of stay
  • Expedited all discharges with transfers to rehabilitation facilities to free up hospital beds
  • Rescheduled all non-urgent spine appointments, such as those for acute back pain without neurologic complications
  • Offered day-surgery nerve root injections to patients with intractable radicular symptoms
  • Continued to receive and operate on emergency spinal trauma and tumor cases

As of April 7, 2020, Singapore instituted a series of heightened measures, collectively referred to as a “circuit breaker,” to further curb community spread of the virus. When the “circuit breaker” kicked in, the spine service again modified its practices. Regular operating and outpatient caseloads were further cut from 50% to 30%. Spine surgery was limited to instances in which a prolonged delay could lead to an irreversible deterioration of function that would negatively impact both the work status and quality of life of the patient.

Precautions during spine surgery are similar to those described by Liang et al for other orthopaedic procedures. Patients with confirmed or suspected COVID-19 and those with pneumonia and unknown COVID-19 status are operated on in a designated OR to avoid contamination of the main operating room and of other patients. In addition:

  • Only selected equipment is brought into the OR to reduce the number of items that require cleaning after the procedure.
  • The presence of health-care personnel is kept to a minimum to minimize exposure.
  • The use of electrocautery is also minimized, with liberal use of suction to remove smoke and aerosols.

Soh et al. also address resident-training issues that were raised in an earlier JBJS fast-tracked article, urging that trainees be reassured they will not be penalized if called upon to modify or sacrifice their training for other responsibilities during this time.

The authors conclude with an acknowledgment of the emotional stress that accompanies a crisis like the COVID-19 pandemic: “During times of crisis, it is important to manage the fears and anxieties of our colleagues as early as possible,” they say. The orthopaedic community must “not forget to look out for one another and bear burdens for one another during this unprecedented time.”

Not All Modes in Multimodal Pain Management are Effective

The public health crisis attributed to opioids has placed increasing emphasis on other approaches to pain management, both pharmacologic and nonpharmacologic. Although some people find the term “multimodal pain management” to be ambiguous when used in clinical research or patient care, it emphasizes the need for a broader (and multidisciplinary) approach to pain management.

On the pharmacologic side, pregabalin has been found to be a variably effective adjunctive analgesic in research involving joint arthroplasty. However, its use in adolescents and children has not been adequately explored. In the February 5, 2020 issue of The Journal, Helenius et al. investigate the impact of pregabalin on total opioid consumption and pain scores in a randomized, placebo-controlled trial of 63 adolescents undergoing posterior instrumented spinal-fusion procedures. These operations are quite invasive and often result in ICU admission because of the amount of narcotics required. In this study, induction and maintenance of anesthesia and mobilization protocols were standardized for patients in both the pregabalin and placebo groups, and the authors precisely measured opioid consumption during the first 48 hours after surgery with data from patient-controlled anesthesia systems.

According to the findings from this adequately powered trial, adjunctive pregabalin did not have a positive impact on opioid consumption or postoperative pain scores. Despite these negative findings, it is my hope that this drug and others being investigated as adjunctive “modes” in multimodal pain management will be subjected to similarly designed trials, so we can accurately determine which agents work best in limiting opioid utilization.

Marc Swiontkowski, MD
JBJS Editor-in-Chief

Vancomycin Powder May Thwart Spinal Fusion

Prompted by relatively high infection rates associated with surgical treatment of pediatric spinal conditions such as scoliosis and spinal-deformity surgery in immunocompromised adults, spine surgeons have led “deep dive” clinical research into the possible benefits of local, intrawound antibiotic therapy. Consequently, the administration of antibiotic powder around the spine’s posterior elements and internal-fixation devices has become fairly widespread. But are there possible downsides to this approach that can impact patient outcomes?

This important question is addressed in the basic-science study by Ishida et al. in the October 2, 2019 issue of The Journal. The authors analyzed the fusion-specific impact of varying concentrations of intrawound vancomycin and tobramycin in a well-characterized rat model of posterolateral fusion performed with syngeneic iliac-crest allograft plus clinical bone-graft substitute. Ishida et al. found that a high dose of vancomycin (71.5 mg/kg, about 5 times higher than spine surgeons typically use) but not tobramycin had detrimental effects on fusion-mass formation in this model, as demonstrated by micro-computed tomography and histological analysis.

We now need further clinical research from the spine community to determine the optimal doses and types of intrawound antibiotics in this setting. Based on the currently available data, power calculations should be performed when designing future trials focused on this question. There seems to be little remaining doubt that locally delivered antibiotics help limit surgical-site and deep infections in spinal surgery. The impact of antibiotics on fusion rates must now be investigated further.

Marc Swiontkowski, MD
JBJS Editor-in-Chief

Mehta Casting for Early-Onset Scoliosis: Predictors of Success

The treatment of early-onset scoliosis with Mehta casting is a long process, but if successful, it can delay or obviate the need for surgery. In the September 4, 2019 issue of JBJS, Fedorak et al. examine outcomes among 38 patients (mean age of 24 ± 15 months at time of first casting) who were treated with Mehta casting and followed for a mean of 8 ± 2 years. The retrospective review identified differences between patients who had a Cobb angle ≤15° (improvement group) at the most recent follow-up and those who had a Cobb angle of >15° (no-improvement group).

Forty-nine percent of children had achieved and maintained scoliosis of ≤15° at the time of the most recent follow-up, and 73% were improved by at least 20°, although 3 children ended up relapsing after meeting recommended criteria for discontinuation of casting. There was no significant difference in thoracic-height gain between the groups, demonstrating that even when scoliosis was not corrected, growth was maintained during cast treatment.

Patients in the improvement group had a mean age of 18.9 ± 12 months and scoliosis of 48.2° ± 14° at the initiation of treatment. Here are 3 additional factors that were associated with a greater likelihood of scoliosis of ≤15°:

  • A lower pre-treatment Cobb angle and traction Cobb angle
  • A smaller rib-vertebral angle difference on first-in-cast radiograph
  • A lower Cobb angle on first-in-cast radiograph

The authors note that although this study analyzed longer-term follow-up data than most other similar investigations, “treatment of early-onset scoliosis is not truly finished until skeletal maturity has been reached.”

Severe Congenital Scoliosis Lowers Exercise Capacity

The etiology and pathogenesis of adolescent idiopathic scoliosis (AIS) and congenital scoliosis are markedly different. Among the differences, progressive congenital scoliosis has the potential to cause much more severe impairment of pulmonary function than does AIS.

In an observational study in the June 19, 2019 issue of The Journal of Bone & Joint Surgery, Lin et al. investigate the precise extent to which pulmonary function and exercise capacity are affected by congenital scoliosis of varying severity. Sixty patients with congenital scoliosis (ranging from 10 to 39 years old) underwent spinal radiography, static pulmonary function testing (PFT), and dynamic cardiopulmonary exercise testing (CPET). From that data the researchers determined the impact of thoracic spinal deformity and rib anomalies on pulmonary function and exercise capacity.

Not surprisingly, PFT results, including total lung capacity, decreased as the severity of thoracic curves increased. In addition, patients with moderate or severe static pulmonary dysfunction had lower exercise tolerance than those with no or mild pulmonary dysfunction. CPET also revealed reduced ventilation capacity, faster respiratory rate, and smaller tidal volume in patients with more complex rib anomalies, although overall exercise tolerance did not differ among patients based on the severity of rib anomalies.

The authors observe that “although patients with thoracic deformities have the potential to compensate during increasing exercise,…exercise capacity (represented by work rate and maximal heart rate) declined greatly in patients with a thoracic curve exceeding 100°.” Because of the connection between congenital scoliosis with pronounced thoracic curves and loss of exercise capacity, Lin et al. recommend “early diagnosis, close follow-up, and timely treatment” for patients with this condition.

What’s New in Spine Surgery 2019

Every month, JBJS publishes a review of the most pertinent and impactful studies published in the orthopaedic literature during the previous year in 13 subspecialties. Click here for a collection of all OrthoBuzz Specialty Update summaries. This month, Jacob M. Buchowski, MD, MS, coauthor of the June 19, 2019 What’s New in Spine Surgery,” selected the five most clinically compelling findings from among the 47 noteworthy studies summarized in the article.

Predictive Analytics for Deformity Conditions
–A validated model for predicting outcomes after lumbar spine surgery1 found that patients with lower preoperative disability scores, those covered by Medicaid or Workers’ Compensation, and current and previous smokers were less likely to improve with lumbar fusion surgery. Invasiveness of surgery and surgeon and hospital type had lower predictive value.

Early-Onset Scoliosis (EOS)
–A 5-year direct-cost estimate2 comparing magnetic growing rods and conventional growing rods for the treatment of EOS found the total cost for magnetic growing rods to be £34,741 compared with £52,293 for conventional growing rods.

Pediatric Neuromuscular Scoliosis
–A Level-II study investigated patient factors associated with postoperative pulmonary complications among patients with neuromuscular scoliosis who underwent posterior spinal fusion.3 Patients with a history of pneumonia or gastrotomy tube at the time of surgery had an elevated risk of postoperative respiratory infections.

Opioid Consumption
–Findings from a retrospective study of >27,000 patients who underwent lumbar decompression with or without fusion revealed that the majority of patients using prescription opioids discontinued those medications postoperatively. However, among the patients with opioid use >90 days after surgery, the duration of preoperative opioid use was the most important predictor of postoperative opioid use.

Neurological Decline after Adult Spinal Deformity Surgery
–In a retrospective analysis of 265 patients who underwent corrective surgery for adult spinal deformity,4 23% of patients experienced a neurological injury; among those, 33% experienced a major neurological decline. Among the patients with major decline, full recovery was observed in 24% at 6 weeks and 65% at 6 months, but one-third of those patients experienced persistent neurological deficits at 24 months postoperatively. Among patients who experienced a minor neurological injury, 49% reported full recovery at 6 weeks and 70% reported full recovery at 6 months. About one-quarter of those patients showed no improvement at 24 months.

References

  1. Khor S, Lavallee D, Cizik AM, Bellabarba C, Chapman JR, Howe CR, Lu D, Mohit AA, Oskouian RJ, Roh JR, Shonnard N,Dagal A, Flum DR. Development and validation of a prediction model for pain and functional outcomes after lumbar spine surgery. JAMA Surg.2018 Jul 1;153(7):634-42.
  2. Harshavardhana NS, Noordeen MHH, Dormans JP. Cost analysis of magnet-driven growing rods for early-onset scoliosis at 5 years. Spine (Phila Pa 1976).2019 Jan 1;44(1):60-7.
  3. Luhmann SJ, Furdock R. Preoperative variables associated with respiratory complications after pediatric neuromuscular spine deformity surgery. Spine Deform.2019 Jan;7(1):107-11.
  4. Kato S, Fehlings MG, Lewis SJ, Lenke LG, Shaffrey CI, Cheung KMC, Carreon LY, Dekutoski MB, Schwab FJ, Boachie-Adjei O, Kebaish KM, Ames CP, Qiu Y, Matsuyama Y, Dahl BT, Mehdian H, Pellisé F, Berven SH. An analysis of the incidence and outcomes of major versus minor neurological decline after complex adult spinal deformity surgery: a subanalysis of Scoli-RISK-1 study. Spine (Phila Pa 1976).2018 Jul 1;43(13):905-12.

June 2019 Article Exchange with JOSPT

In 2015, JBJS launched an “article exchange” collaboration with the Journal of Orthopaedic & Sports Physical Therapy (JOSPT) to support multidisciplinary integration, continuity of care, and excellent patient outcomes in orthopaedics and sports medicine.

During the month of June 2019, JBJS and OrthoBuzz readers will have open access to the JOSPT article titled “Hybrid Approach to Treatment Tailoring for Low Back Pain: A Proposed Model of Care.”

The authors of this clinical commentary propose a hybrid, prognosis-based approach to low back pain management that includes psychologically informed treatments for those with medium risk and a predominantly central pain mechanism and motor-control approaches to exercise for individuals with medium risk and a nociceptive pain mechanism.

May 2019 Article Exchange with JOSPT

In 2015, JBJS launched an “article exchange” collaboration with the Journal of Orthopaedic & Sports Physical Therapy (JOSPT) to support multidisciplinary integration, continuity of care, and excellent patient outcomes in orthopaedics and sports medicine.

During the month of May 2019, JBJS and OrthoBuzz readers will have open access to the JOSPT article titled “Cervical Muscle Endurance Performance in Women With and Without Migraine.”

The authors of this cross-sectional laboratory study found that a group of 26 female patients with migraine exhibited a lower holding time for both neck-extensor and neck-flexor endurance than a group of 26 women without migraine. Both groups reported a similar level of neck pain, but only individuals in the migraine group reported pain referred to the head during testing.