Selective Dorsal Rhizotomy for Spasticity Periprocedural Care

Updated: Dec 11, 2018
  • Author: Richard CE Anderson, MD; Chief Editor: Kim J Burchiel, MD, FACS  more...
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Periprocedural Care

Patient Education & Consent

It is essential for the family and interdisciplinary health care team to understand and agree upon the goals of surgical intervention in spasticity. With the correct patient selection and postoperative rehabilitation, children with spasticity can experience marked improvements in lower extremity function, range of motion, and global function following selective dorsal rhizotomy (SDR). With an irreversible procedure such as SDR, however, expectations should be clearly defined and realistic outcomes delineated.

The ability to participate in a rigorous postoperative physical therapy program is essential and must be discussed with families and caregivers in advance. [11]

Patient Instructions

All patients undergo general anesthesia so are required to be kept on nil per os (NPO; nothing by mouth) from midnight the night before surgery. Patients are sometimes instructed to use a special cleansing soap the night prior and morning of surgery in order to minimize the risk of surgical infection. Patients may expect to be kept flat in bed the first day or two postoperatively in order to minimize the risk of cerebrospinal fluid leakage.

Elements of Informed Consent

Patients must be aware the goal of surgery is reduction of motor tone, which has various functional implications based on the patient’s age, functional status, strength, and ability to engage in postoperative physical therapy. They must be aware that the consequences of rootlet transection are irreversible. The patient should also be informed of the risk of cerebrospinal fluid leak from an intradural operation.

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Pre-Procedure Planning

Preoperative MRI and intraoperative ultrasonography are helpful to determine if additional bone removal is needed to achieve adequate exposure around the conus.

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Equipment

Preoperative neurophysiologic monitoring electrodes are placed after intubation. Needle electrodes are typically placed in the adductor magnus (longus or brevis) (L2-4), vastus lateralis (L2-4), anterior tibialis (L4, L5), bicep femoris (L5, S1), gastrocnemius (S1, S2), and external anal sphincter muscles (S2-S4) in preparation for intraoperative electromyography (EMG).

Ultrasonography is used to ensure adequate bone removal

An operating microscope is used for the intradural portion of the case.

Rhizotomy stimulating electrodes and routine microinstruments should be made available.

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Anesthesia

The anesthetic regimen is critical to intraoperative evaluation by the neurophysiologist and physiotherapy team. Premedication with a short-acting benzodiazepine and induction agents such as sevoflurane and remifentanil are frequently used. Subsequently, propofol, benzodiazepines, and paralytics are avoided because of the alteration of EMG activity.

Anesthesia is often maintained with fentanyl, nitrous oxide, and sevoflurane.

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Positioning

The patient is placed in a prone position, with soft supports under the chest and hips, and appropriate padding of the knees, feet, and arms. The patient’s head is placed in a soft foam head-holder with the breathing tube to the side. The patient’s arms are typically placed at 90° at the shoulder and elbows, in a cephalad direction, in order to allow the surgeon access to the lumbosacral spine and anesthesiologist better access to lines. In smaller children, the arms may be left at the side of the hips in anatomical position, if desired.

If manual palpation of muscle groups is performed intraoperatively to assess response during nerve rootlet stimulation, the patient’s feet should be close to the bottom of the bed to allow adequate access for the therapists under the operative drapes.

If a traditional SDR is performed, a five- or six-level laminoplasty is typically done to expose the entire cauda equina. If a SDR centered at the conus is performed, fluoroscopy is used to localize L1. Preoperative MRI and intraoperative ultrasonography are helpful to determine if additional bone removal is needed to achieve adequate exposure around the conus.

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Monitoring & Follow-up

Initial management includes transfer to the PICU and then to the neurosurgical ward with intravenous and then oral pain medications, as needed.

Antibiotics are continued for 24 hours, and steroids for 72 hours postoperatively.

The patient may be kept flat for 1-3 days postoperatively to promote healing and to reduce the risk of cerebrospinal fluid leak.

Recovery from surgery typically takes 2-3 days.

Immediately after surgery, patients typically have a significant reduction in spasticity, often unmasking underlying muscle weakness. [14] Pudendal monitoring, in an attempt to avoid such complications, is practiced by many institutions. [15] Although studies have proposed an increased incidence of scoliosis and hip subluxation following SDR, the common finding of these conditions in patients with spasticity who have not undergone SDR leave the role of SDR in the causation of these conditions unclear. [22, 23, 24]

Long-term monitoring

Several studies have documented positive outcomes from SDR. Muscle tone, flexibility, gait pattern, functional positioning, and the functional ability of the child have all been documented as improving following SDR. [20, 25, 26] Of note, SDR did not eliminate the need for further orthopedic surgery in approximately half of patients requiring further tendon-lengthening procedures. The need for subsequent orthopedic procedures has also been reported in other studies; however, it is likely that these procedures would have been necessary regardless of SDR. [27]

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