Vol. 14 Issue 16
A Surgical Option for Spasticity
Selective dorsal rhizotomy gains steam in the management of CP
For Laurie (name changed), selective dorsal rhizotomy was the only option for her 3-year-old son, at least in her mind.
Laurie's son was diagnosed at 13 months with mild cerebral palsy, and his doctors did not paint a pretty picture of his future without some type of interventionrepeated orthopedic surgeries for tendons, hamstrings, knees and hips; foot and ankle orthoses for life; balance and coordination problems...there seemed no end to the list.
So when physicians assessed the boy's movement patterns and described SDR as a realistic option for him, Laurie jumped at the chance. She knew the three-hour surgery and subsequent period of intense postop rehab were an easy trade-off for the priceless improvements to his quality of life: no more surgeries for the rest of his life, resolution of balance and coordination issues, and a sharp reduction in the spasticity that stiffened his leg muscles so tight that walking was a chore.
"I wasn't even willing to consider another opinion," Laurie said. "We are now 10 months past the surgery, and some days we cannot believe how well he is able to walk flat-footed and upright. We still have rehab to do, but we are down to two days per week of PT already. He's still [using] ankle-foot orthoses, but they will go in the future."
Selective Dorsal Rhizotomy Defined
Laurie's son was the recipient of almost a century of research into analyzing and refining selective dorsal rhizotomy (SDR), to the point that an absolute minimum of bone and tissue is now disturbed during the technique.
Working from the assumption that spasticity arises from an interruption in the nerve circuitry of the brain and spinal column, early surgeons wondered if selectively cutting the offending nerves could shut down the faulty circuit and ease spastic symptoms in the proximal muscles of children with CP. They tried it as early as 1913.
While success was seen in these formative years, real progress surrounding SDRand raised eyebrows from the staunch neurosurgical communitydidn't come about until the 1970s. Unlike many surgeries, SDR has stood the test of time, and for many children with spastic CP it remains the best chance of being able to crawl, sit, stand, walk and play without constant medication.
Put simply, dorsal spinal roots transmit sensation from muscles to the spinal cord, while ventral roots transmit information (such as the command to contract) from the spine back to the muscle. It's the dorsal roots that surgeons target during SDR.
By selectively isolating these nerve roots, then stimulating each electrically and analyzing corresponding muscle response through EMG, surgeons are able to determine which rootlets are firing inappropriately. These faulty fibers are then sectioned off, greatly diminishing the transmission of improper commands to the central nervous system and reducing spasticity in muscles.
But pediatric specialists are quick to point out that surgery doesn't displace the need for intense physical therapy. In fact, both before and after the procedure, skilled PTs are needed more than ever.
PTs and Pre-Screening
Neurosurgeon T. S. Park, MD, director of the Center for Cerebral Palsy Spasticity at St. Louis Children's Hospital (affiliated with Washington University in St. Louis), is a forerunner in the field and has performed more of these delicate procedures than any other surgeon, according to Time Magazine (Feb. 25, 2002). Pre-screening and postoperative rehab for Dr. Park are handled by Joan Puglisi, PT, PCS, rehab coordinator at the center.
"Your best candidates for SDR are kids with typical spastic diplegia, and good strength," said Puglisi, who assesses ROM, motor control, gait, wheelchair needs and orthotics with families, as well as discussing pre- and postsurgical PT protocols. "Most of the families we see come to us from out of town, on a recommendation from their pediatrician, orthopedist or therapist." Sessions are videotaped to compare pre- and postsurgical functional levels.
Puglisi explained that children who present with mixed tone, athetosis or dystonia don't historically benefit as much from the SDR procedure.
"We also hope to see some degree of balance and underlying strength," added Mary Soley, MSPT, senior therapist at the Hyman-Newman Institute for Neurology and Neurosurgery, a division of Beth Israel Medical Center in New York. Soley works alongside neurosurgeon Richard Abbott, MD, in a capacity similar to Puglisi's.
"We look for strong isolated movement patterns in different postures, as well as in crawling, bunny-hopping, or whatever their preferred method of locomotion may be," Soley said, adding that true strength can be a challenging element to measure, given the spasticity that often masks it.
Soley hopes for good co-contraction and coordinated movement also, and tests for it with the squat-to-stand test. And being able to perform multiple repetitions can point to good muscle endurance, another predictor of a positive SDR outcome.
The ideal age for SDR is generally between 2 and 5, since spasticity may inhibit longitudinal muscle growth, and muscle contractures and orthopedic deformities can magnify as a child grows.
PTs and Postsurgical Rehab
Most children bounce back from SDR relatively swiftly, and are usually able to cope with declining inpatient stays that insurance payers have whittled from two to three months down to mere days. Rehab therapists generally encourage sitting up in bed and getting into a wheelchair by day two.
"On the third day after the procedure, we start to introduce gentle PT twice a day," Puglisi said, including mild active and passive ROM, light strengthening and other movements for motor control. "By day four, they're usually ready to go down to the department gym, and work on whatever strengthening they're capable ofrolling, crawling, sit-to-stand or supported walking, for instance."
After an inpatient stay, Puglisi sends them back home with a specific PT protocol to achieve strengthening, alignment and isolated movements, and follows up with phone consultations.
Soley and the Beth Israel team recommend an ideal inpatient stay of six weeks, and send many children to the nearby Rusk Institute of Rehabilitative Medicine for it. But in cases where the family and therapy team are strongly dedicated and familiar with SDR rehab, the children can be sent home and supported with follow-up consults and outpatient visits to a local facility.
"I'm always asked if there's a specialized protocol for children after having this procedure," Soley said. "But in most cases, it follows the same type of approach you'd have for children with CP who don't have the operationstretching, gait training and functional activities to facilitate improvements in movement patterns and muscle recruitment. We always encourage natural activity, and the child is free to move as they wish, with a few passive positioning precautions in the first six weeks."
Despite the impressive outcomes surrounding SDR, surgery is surgery, and carries the risks and complications one would expect from such an intricate spinal procedure. Temporary sensory loss, weakness and skin sensitivity are quite common, but usually resolve in several weeks. Generally, SDR does not replace a need for orthopedic surgery. In very rare cases, paralysis of the legs and bladder, impotence and sensory loss can occur, and leakage of spinal cord fluid has been reported.
"We've performed over a thousand of these operations at the center, and we've never had a serious complication," said Puglisi, who said most would be caught by the physicians who consult with their patients daily.
Many pediatric specialists continue to eye the surgery with caution. Andrew Ball, PhD, MBA, PT, a North Carolina-based clinician and freelance adjunct professor with extensive history in pediatrics, cautions that because of the permanency of the procedure, all noninvasive options should be exhausted first.
"Once the dorsal roots are cut, the sensory system is compromised, and the potential prognosis from partial-weight bearing treadmill training (PWBTT) drops dramatically," noted Dr. Ball, referring to treadmill exercise while partially buoyed in a harness, which has been studied in patients following stroke, SCI and other neurotrauma, and that shows promise in children with CP. "This is due to the fact that PWBTT's central pattern generator stimulation and effectiveness depends on intact sensory tracts to the medulary locomotor region."
And while medical professionals are becoming more aware of PWBTT as an alternative to surgery for these children, in Dr. Ball's experience this training remains far behind other minimally invasive alternatives such as botox in the child's presurgical approach. "I really wish more PTs would push the PWBTT option to the surgeons before that option is lost forever," he said.
Susan Guzzardo, DPT, assistant professor at Touro College in New York, worked with Soley and Dr. Abbott in screening and rehabbing children who underwent rhizotomy procedures for 15 years before taking on her current teaching appointment. Even before coming to Beth Israel, she followed up on many of Dr. Abbott's cases as an inpatient therapist at the Rusk Institute.
Dr. Guzzardo noted that she has seen a marked decline in the number of SDR operations performed today, compared to just a few years ago. "I think it's a result of how neonatology and prenatal care are going," Dr. Guzzardo said. "Kids with CP today are not presenting with pure spasticity as much anymore, so good candidates for SDR are becoming more rare."
But don't take that as an encouraging sign that CP is vanishing from the medical landscapeother patterns of CP that result in a more mixed-tone presentation are on the rise, Dr. Guzzardo said, and the incidence of CP on the whole seems to be climbing.
Furthermore, despite the decline in pure spastic diplegia, Dr. Guzzardo does not see rhizotomy disappearing from the medical textbooks either, since good candidates will always be found; she intends to include SDR along with other forms of spasticity management as she constructs her lesson plan for pediatrics classes at Touro in the fall.
"If you're a good candidate for this procedure, you can be helped tremendously," Dr. Guzzardo maintained. "I strongly feel that it's a better option in most cases than something that is going to require constant management, such as baclofen pumps or repeated injections of botox. This is one procedure, followed by a period of intense rehab, and once it's over, that spasticity is never going to return. The only problem is that the best candidates are becoming harder and harder to find."
Contact the sources of this article at the following e-mail addresses: Joan Puglisi, firstname.lastname@example.org; Mary Soley, email@example.com; Andrew Ball, firstname.lastname@example.org; Susan Guzzardo, email@example.com
Jonathan Bassett is on staff at ADVANCE, and can be reached at firstname.lastname@example.org