Complication Review Pediatr Neurosurg 1992;18:43-47
Division of Pediatric Neurosurgery. New York University Medical Center. New York. N.Y., USA
Complications with Selective Posterior Rhizotomy
Keyw ords
Abstract
Rhizotomy Complications Bronchospasm Aspiration pneumonia Bladder dysfunction Hip dislocation
Since 1986 250 patients have undergone selective posterior rhizotomy for spastic cerebral palsy at New York University Medical Center. Severe, peri operative complications were experienced by 15% of these patients and con sisted of bronchospasm. aspiration pneumonia, urinary retention, ileus, sen sory loss. Additionally, most of our patients had severe pain immediately after the surgery and nearly half had dysesthesias for up to 3 weeks. Long-term complications such as decreasing range of muscle movement and hip disloca tion are now becoming apparent. This patient population must be viewed as having special risks attendant with surgery and particularly with selective pos terior rhizotomy.
Introduction
Cerebral palsy is a common physical disability in childhood that results from a central nervous system injury during the perinatal period [ 1]. The spastic form is characterized by increased muscle tone resulting in a decreased range of motion and an impairment of motor function. Selective posterior rhizotomy (SPR), a modifi cation of the classical sensory rhizotomy, followed by an intensive rehabilitation program provides a new alternate treatment for treating the functional disabilities associ ated with spasticity [2, 3]. Since 1986 we have performed SPRs on over 250 chil dren with spastic diplegia and quadriplegia at New York University Medical Center (NYUMC). We have seen sev eral types of perioperative and long-term complications among these patients (table 1). It will be the purpose of this chapter to describe them as well as the protective measures adopted to prevent them.
Table 1. Incidence of complications (NYUMC)
Number Pulmonary Bronchospasm intraoperative Aspiration pneumonia Bowel and bladder Urinary retention Constipation Ileus Postoperative discomfort Pain, severe Dysesthesias Sensory alteration Proprioceptive loss Pain/temperature loss
Rick Abbott. M l) Division of Pediatric Ncurosurgcr) New York University Medical Center New York. NY (USA)
%
13 5
5 2
13 49 3
5 20 1
145 100
58 40
3 2
1 1
© I992 S. Karger AG. Basel 10 16—2291/92/018 1— 0043 $2.75/0
Downloaded by: Stockholm University Library 130.237.165.40 - 2/27/2018 5:05:41 PM
Rick Abbott
Bronchospasm Children born prematurely or requiring either O: sup plementation or mechanical ventilation are known to have a much higher incidence of airway hyperactivity (at least 5 times greater than the general population) [4-6]. Addition ally, children with a history of meconium aspiration have a 3-fold increase in the incidence of bronchial hyperactiv ity [7], A perinatal history of meconium aspiration or ven tilatory support is not unusual in the cerebral palsy popu lation. Children at greatest risk for the development of perioperative bronchospasm typically are the more se verely impaired diplegics or quadriplegics born 2-4 months prematurely with evidence of hyaline membrane disease [8], They frequently require mechanical ventila tion at this time. Their respiratory compromise continues beyond the 1st month of life with a patent ductus arterio sus and feeding intolerance frequently becoming evident [18]. Respiratory problems often continue after discharge (3+ months after birth) with recurrent episodes of bronchi tis, aspiration pneumonia or episodic wheezing, especially at times of upper respiratory infections [8], Children who have a history of bronchodilator use for the treatment of asthma or bronchitis are also at risk for the development of intraoperative bronchospasm. These are children with a subclinical case of bronchopulmonary dysplasia not elic ited in the patient’s health history. Of the 250 patients who have undergone SPR at NYUMC, 13 experienced intra operative bronchospasm with 5 of these requiring prema ture ending of the procedure. At NYUMC the current management of the patients at risk for developing bronchospasm is to administer intra venous aminophylline during the pre-, intra- and postop erative period. A bolus dose of 6 mg/kg of intravenous aminophylline is given the evening before surgery and is followed with a continuous infusion of the drug at a rate of 1 mg/kg/h. This infusion continues throughout the pro cedure and postoperatively until there is no sign of respi ratory compromise (typically 24 h after the surgery). This protocol has now been used on 190 children and we have only seen bronchospasm in 2: 1 during the surgery and I after the surgery. In neither case did the bronchospasm compromise the surgery or the child’s recovery from it. Aspiration Pneumonia Aspiration pneumonia is frequently seen in children with more advanced cases of cerebral palsy [9], 10-15% of the severely involved cerebral palsied children have a history of recurrent vomiting ( > 8 episodes/month) [8],
44
Abbott
This vomiting can result in hyperactive airway disease or aspiration with subsequent pneumonia [10, 11]. Aspira tion pneumonia as a complication of a surgical procedure occurs most frequently in children who have a history of gastroesophageal reflux [ 12], Euler et al. [II] reported that 18/19 individuals with documented gastroesophageal re flux had a history' of recurrent pneumonia. These patients frequently have a history of nocturnal coughing (89%), recurrent pneumonias (94%) and a history of vomiting during infancy (42%) [11]. The children most at risk for aspiration pneumonia are also the most severely involved cognitively and have the greatest degree of spasticity [8. 12, 13], Children with a history of reactive airway disease should also be suspect since their reactive airway disease may be due to occult esophageal reflux [10, 11]. Lastly children with an enlarged gastric bubble on the preopera tive X-ray arc also at risk for developing an aspiration pneumonia. At NYUMC 5 of our rhizotomy patients developed aspiration pneumonia postoperatively with 3 of these requiring artificial ventilation with PEEP for at least 18 h after surgery. Two patients had a major lung segment or lobe collapse of unclear etiology during surgery resulting in the abandonment of the surgery and a period of postop erative artificial ventilation with PEEP. Measures used at NYUMC to avoid aspiration pneumonia are obvious. Abdominal x-rays are checked for signs of an enlarged gastric bubble heralding gastric stasis. Children with a his tory of gastric reflux or pneumonia are given a Hi blocker to decrease the acidity of the gastric contents to decrease its harmfulness if aspirated. Since the introduction of Hy blocker use, 180 rhizotomies have been performed with out a seerious case of aspiration pneumonia occurring.
Bowel and Bladder Dysfunction
Urinary Retention Children with cerebral palsy are at risk to develop a symptomatic neurogenic bladder. McNeal ct al. [14] re ported an 8% incidence of neurogenic bladder by cystometrograms and a 36% incidence of symptoms suggesting neurogenic bladder (enuresis, stress incontinence and dribbling) in 50 individuals interviewed at a cerebral palsy center. Postrhizotomy urinary retention may be a result of several factors. A loss of blood supply to the conus secondary to severing of important radicular arter ies may occur during the surgery leading to an infarct within the conus. Contusion of motor roots within the cauda also could explain any bladder dysfunction. Addi
Selective Posterior Rhizotomy
Downloaded by: Stockholm University Library 130.237.165.40 - 2/27/2018 5:05:41 PM
Respiratory Complications
Constipation and Ileus Postoperative gastrointestinal problems include con stipation as well as transient ileus. 3/250 children devel oped a postoperative ileus requiring 48 h of suctioning via a nasogastric tube. 20-25% of the children have trouble moving their bowels after the surgery. These adverse effects may be because of a predisposition to constipation or effects of anesthesia and postoperative narcotics. We are impressed that these children are very susceptible to postoperative constipation/ileus. For that reason we have become very conservative with their dietary advancement postoperatively.
Postoperative Discomfort
Discomfort is a near universal feature of the imme diate postoperative recovery period. Nearly all patients who have the selective rhizotomy procedure experience moderate to severe postoperative pain for the first 4872 h postoperatively. This is frequently accompanied by back spasms and an increase in the individual's baseline muscle tone. Nearly half the patients also will experience dysesthesias in a stocking distribution in the legs. Morphine sulfate 0.15-0.2 mg/kg subcutaneously ev ery 3-4 h is necessary for 24-48 h postoperatively. This is frequently augmented with a benzodiazepam to abort an escalating pain-spasm cycle. The pain dramatically disap pears in the 2nd to 3rd postoperative day allowing the dis continuance of narcotic pain medication. Parental prepa ration for the intensive postoperative pain will reduce their anxiety and allow them to focus their attention on comforting their child. During the immediate postoperative period children in severe discomfort may have persisting spasticity in their legs. Increased spasticity also may be evident during times of increased stress (due to illness, anxiety, etc.) for months and even years following surgery. We have now seen this in 10 of our patients, all of whom were spastic quadriplegics preoperatively. Dysesthesias or ‘needles and pins’ sensations in the legs are also common during the postoperative period. It has been reported as a side effect of sensory rhizotomies used to treat localized pain syndromes [16]. This is the same type of unpleasant sensation that occurs in spinal cord injury, expanding syringes and after surgery for intramedullary spinal cord tumors. It has been theorized that this represents an imbalance between the dorsal col umn fibers and spinothalamic fibers within the affected individual's spinal cord. The theory arose from observing individuals with spinal cord injuries resulting in a loss of pain and temperature sensation but preservation of dor sal column sensation [17]. As the utility of selective sen sory rhizotomy in treating spasticity was discovered serendipitously during its application to treat pain syn dromes. it should not be surprising that the density of pain fibers in those rootlets cut to treat spasticity is greater than those preserved. These dysesthetic sensa tions typically decrease in intensity with time in our patients and usually require no treatment other than patient/parental reassurance. Frequently these dysesthe sias are lessened if the child wears socks while in bed or therapy. On rare occasions carbamazepine has been used to treat the condition.
45
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tionally, since some children’s bladders may be depen dent upon spasmodic evacuation preoperatively, deafferentation could result in a decrease in ability to evacuate. The reduction in spasticity that occurs with the severing of the nerve rootlets would then leave the child with a hypotonic bladder requiring intermittent catheterization on either a temporary or permanent basis. Most impor tantly, we have discovered that there is a variability in the distribution of afferent pudendal nerve fibers within the cauda equina [ 15]. We have found that the afferent fibers of the penile/clitoral cutaneous branch of the pudendal nerve can be confined to a single, unilateral sacral root. Therefore, we postulate that fibers involved in the blad der’s reflex circuits could be isolated to a single root within the target zone of the SPR surgery. Postoperative urinary retention requiring intermittent catheterization has been necessary in 13 of the 250 patients who have undergone the rhizotomy procedure at NYUMC. One patient is still dependent on a catheteriza tion program 18 months after surgery. Children at great est risk for the development of postoperative bladder complications include those with a history suggesting a spastic bladder. This includes those with histories of recurrent urinary tract infections or constipation. De layed toilet training or the incidence of daytime inconti nence are also symptoms suggesting bladder spasticitv [14]. Clinical management of children should include pre operative cystometrograms for those with histories sug gesting spastic bladders. Parents should be warned of the possibility of intermittent catheterization for a period after the surgery and of the remote possibility of perma nent bladder dysfunction. Intraoperatively, we use prelesioning pudendal neurograms to avoid lesioning of root lets with significant pudendal afferent activity [15].
Alteration in Sensation Four of our patients have experienced focal areas of sensory loss postoperatively. Three of these patients have loss proprioception in one of their ten toes and one patient has loss pain and temperature sensation in the right SI dermatome. These deficits remained at their 6month postoperative réévaluation.
Long-Term Complications
We have now been able to follow over 50 patients for more than 2 years post-rhizotomy. We are becoming increasingly aware of several long-term complications that can potentially arise. Of utmost concern is the poten tial for functional decline in these patients. Several au thors have mentioned that the alleviation of spasticity can result in a decline in leg function if the spasticity is being used to help in weight bearing [18-21], This can be avoided by examining the patients’ concentric and eccen tric strength in their antigravity muscles. Using a simple test such as the ability to slowly rise out of a squat to stand and then lower back into a squat will examine a child’s antigravity strength [18]. A demonstrated ability to do this predicts adequate strength to bear the body’s weight standing. Loss in Muscle Range Many children we have been able to follow after their surgery have presented with progressive loss in muscle range of motion. This typically occurs in the hip adduc tors, hamstrings and gastrocnemius muscles. A history of a recent growth spurt is common. Most importantly, all the children who experienced this were not obtaining clasical muscle stretching therapy during the growth spurt. The loss of muscle range typically resulted in a deteriora tion in the child’s gait pattern and. usualy, the range loss could be reversed with an aggressive muscle stretching program. In 8 children, however, tendonotomies were required to regain the loss muscle range. This complica tion underlines the importance of maintenance therapy in these children, particularly during times of rapid growth. This is because muscle contractures persist in the legs' musculature although the spasticity has been treated.
dysplasia who undergo SPR are at a higher risk for pro gressive dislocation when compared to children with nor mal hips who undergo SPR. Six of our patients have now undergone varus derotation osteotomies of the femurs for progressive dislocation of the hips. All these children were crawling before their surgery and after their surgery ad vanced to use walking as their main mode of locomotion. When walking these children exhibited poor control of hip alignment during terminal stance phase due to weak ness in their hip abductors and hip extensors. We now obtain preoperative hip X-rays and place children whom we think are at risk for hip subluxation in orthosis with single lateral upright bracing attached to a pelvic band after their surgery. This is done to support the hip joint during ambulation.
Conclusion
Postoperative complications of the SPR procedure oc cur in a small percentage of the operative cases. At NYUMC we feel that these complications can be mini mized or avoided by identifying those children at risk with detailed history and physical examination. These patients can then receive prophylactic treatment or care ful monitoring for prevention or treatment of such com plications. Additionally, it is vital that the family be aware of those risks for permanent dysfunction and those which cause transient discomfort or dysfunction.
46
Abbott
Selective Posterior Rhizotomy
Downloaded by: Stockholm University Library 130.237.165.40 - 2/27/2018 5:05:41 PM
Hip Dislocation Progressive dislocation of the hips is possible after SPR. Greene et al. [22] have recently reported rapid sub luxation of the hips in 6 children who had undergone SPR. It was their feeling that children with preexisting hip
References 9
10
11
12
13
14
15
Sondheimer JM. Morris BA: Gastroesophageal reflux among severely retarded children. .1 Pe diatr 1979:94:710-714. Bcrquist WE. Rachelefsky GS. Kadden M. Sie gel SC. Katz RM. Fonkalsrud EW. Ament ME: Gastroesophageal reflux-associated recurrent pneumonia and chronic asthma in children. Pediatr 1981:68:29-35. Euler AR. Byrne WJ. Ament ME. Fonkalsrud EW. Strobel CT. Siegel SC. Katz RM. Rachel efsky GS: Recurrent pulmonary disease in chil dren: A complication of gastroesophageal re flux. Pediatr 1979:63:47-51. Drvaric DM. Roberts JM. Burke SW. King AG. Falterman K: Gastroesophageal valuation in totally involved cerebral palsy patients. J Pediatr Orthop 1987;7:187-190. Abrahams P. Burkitt BFE: Hiatus hernia and gastro-oesophageal reflux in children and ado lescents with cerebral palsy. Aust Pediatr 1970: 6:41-46. McNeal DM. Hawtrey CE, Wolraich ML. Mapel JR: Symptomatic neurogenic bladder in a ccrebral-palsv population. Dev Med Child Neurol 1983:25:612-616. Deletis V. Vodusck D. Abott R. Epstein FJ. Tum dof H: Intraoperative monitoring of dor sal sacral roots. Minimizing the risk of iatro genic micturalion disorders. Neurosurgery 1992:30:72-75.
16 White JC. Kjellberg RN : Posterior rhizotomy: A substitute for cordotomy in the relief of local ized pain in patients w ith normal life-expectan cy. Neurochirurgia 1973:16:141-170. 17 Beric A, Dimitrijevic MR. Lindblom U: Cen tral dysesthesia syndrome in spinal cord inujury patients. Pain 1988:34:109-116. 18 Elk B: Pre-operative assessment and post-surgi cal occupational therapy for children who have undergone a selective posterior rhizotomy. S Afr J Occup Thcr 1984:14:45-50. 19 Foerster O: On the indications and results of the excision of posterior spinal roots in men. SurgGyn Obst 1913:16:463-475. 20 Peacock WJ. Stout LA: Functional outcome following selective posterior rhizotomy in chil dren with cerebral palsy. J Neurosurg 1991:74: 380-385. 2 1 Privât JM. Benezcch J. Frerebrau P. Gros C: Sectorial posterior rhizotomy, a new technique o f surgical treatment of spasticity. Acta Neuroehir 1976:35:181-195. 22 Greene WB. Dietz FR. Goldberg MJ. Gross RH, Miller F. Sussman MD: Rapid subluxa tion in cerebal palsy after selective posterior rhizotomy. .1 Pediatr Orthop 1991:11:494497.
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1 Huttenlocher PR: Cerebral palsy; in Vaugham VC. McKay RJ. Nelson WE(eds): Nelson Text book of Pediatrics, ed 10. Philadelphia. Saun ders. 1975, pp 1423-1425. 2 Abbott R, Forcm SL. Johann M: Selective pos terior rhizotomy for the treatment of spasticity; A review. Childs Nerv Syst 1989;5:337-346. 3 Peacock WJ. Arens U . Berman B; Cerebral palsy spasticity. Selective posterior rhizotomy. Pediatr Ncurosci 1987;13:61-66. 4 Bader D. Ramos AD. Lew CD. Platzer ACG. Stabile MW. Keens TG: Childhood sequelae of infant lung disese: Exercise and pulmonary function abnormalities after bronchopulmo nary dysplasia. J Pediatr 1987;110:448-456. 5 Bertrand JM. Riley SP. Popkin J. Coates AL: The long term pulmonary' sequelae of prema turity: The role of familial airway hyperactivity and the respiratory distress syndrome. N Engl J Med 1985:312:742-745. 6 Coates AL. Bergsteinsson H, Desmond K. Outerbridge EW. Beaudry' PH: Long-term pulmo nary sequelae of premature birth with and without idiopathic respiratory distress syn drome. J Pediatr 1977:90:611-616. 7 Swaiminathan S. Quinn J. Stabile MW. Bader D, Platzker ACG. Keens TG: Long-term pul monary sequelae of meconium aspiration syn drome J Pediatr 1989; 114:356-361. 8 Nickerson BG: Bronchopulmonary dysplasia: Chronic pulmonary disease following neonatal respiratory failure. Chest 1985:87:528-535.
Division of Pediatric Neurosurgery. New York University Medical Center. New York. N.Y., USA
Complications with Selective Posterior Rhizotomy
Keyw ords
Abstract
Rhizotomy Complications Bronchospasm Aspiration pneumonia Bladder dysfunction Hip dislocation
Since 1986 250 patients have undergone selective posterior rhizotomy for spastic cerebral palsy at New York University Medical Center. Severe, peri operative complications were experienced by 15% of these patients and con sisted of bronchospasm. aspiration pneumonia, urinary retention, ileus, sen sory loss. Additionally, most of our patients had severe pain immediately after the surgery and nearly half had dysesthesias for up to 3 weeks. Long-term complications such as decreasing range of muscle movement and hip disloca tion are now becoming apparent. This patient population must be viewed as having special risks attendant with surgery and particularly with selective pos terior rhizotomy.
Introduction
Cerebral palsy is a common physical disability in childhood that results from a central nervous system injury during the perinatal period [ 1]. The spastic form is characterized by increased muscle tone resulting in a decreased range of motion and an impairment of motor function. Selective posterior rhizotomy (SPR), a modifi cation of the classical sensory rhizotomy, followed by an intensive rehabilitation program provides a new alternate treatment for treating the functional disabilities associ ated with spasticity [2, 3]. Since 1986 we have performed SPRs on over 250 chil dren with spastic diplegia and quadriplegia at New York University Medical Center (NYUMC). We have seen sev eral types of perioperative and long-term complications among these patients (table 1). It will be the purpose of this chapter to describe them as well as the protective measures adopted to prevent them.
Table 1. Incidence of complications (NYUMC)
Number Pulmonary Bronchospasm intraoperative Aspiration pneumonia Bowel and bladder Urinary retention Constipation Ileus Postoperative discomfort Pain, severe Dysesthesias Sensory alteration Proprioceptive loss Pain/temperature loss
Rick Abbott. M l) Division of Pediatric Ncurosurgcr) New York University Medical Center New York. NY (USA)
%
13 5
5 2
13 49 3
5 20 1
145 100
58 40
3 2
1 1
© I992 S. Karger AG. Basel 10 16—2291/92/018 1— 0043 $2.75/0
Downloaded by: Stockholm University Library 130.237.165.40 - 2/27/2018 5:05:41 PM
Rick Abbott
Bronchospasm Children born prematurely or requiring either O: sup plementation or mechanical ventilation are known to have a much higher incidence of airway hyperactivity (at least 5 times greater than the general population) [4-6]. Addition ally, children with a history of meconium aspiration have a 3-fold increase in the incidence of bronchial hyperactiv ity [7], A perinatal history of meconium aspiration or ven tilatory support is not unusual in the cerebral palsy popu lation. Children at greatest risk for the development of perioperative bronchospasm typically are the more se verely impaired diplegics or quadriplegics born 2-4 months prematurely with evidence of hyaline membrane disease [8], They frequently require mechanical ventila tion at this time. Their respiratory compromise continues beyond the 1st month of life with a patent ductus arterio sus and feeding intolerance frequently becoming evident [18]. Respiratory problems often continue after discharge (3+ months after birth) with recurrent episodes of bronchi tis, aspiration pneumonia or episodic wheezing, especially at times of upper respiratory infections [8], Children who have a history of bronchodilator use for the treatment of asthma or bronchitis are also at risk for the development of intraoperative bronchospasm. These are children with a subclinical case of bronchopulmonary dysplasia not elic ited in the patient’s health history. Of the 250 patients who have undergone SPR at NYUMC, 13 experienced intra operative bronchospasm with 5 of these requiring prema ture ending of the procedure. At NYUMC the current management of the patients at risk for developing bronchospasm is to administer intra venous aminophylline during the pre-, intra- and postop erative period. A bolus dose of 6 mg/kg of intravenous aminophylline is given the evening before surgery and is followed with a continuous infusion of the drug at a rate of 1 mg/kg/h. This infusion continues throughout the pro cedure and postoperatively until there is no sign of respi ratory compromise (typically 24 h after the surgery). This protocol has now been used on 190 children and we have only seen bronchospasm in 2: 1 during the surgery and I after the surgery. In neither case did the bronchospasm compromise the surgery or the child’s recovery from it. Aspiration Pneumonia Aspiration pneumonia is frequently seen in children with more advanced cases of cerebral palsy [9], 10-15% of the severely involved cerebral palsied children have a history of recurrent vomiting ( > 8 episodes/month) [8],
44
Abbott
This vomiting can result in hyperactive airway disease or aspiration with subsequent pneumonia [10, 11]. Aspira tion pneumonia as a complication of a surgical procedure occurs most frequently in children who have a history of gastroesophageal reflux [ 12], Euler et al. [II] reported that 18/19 individuals with documented gastroesophageal re flux had a history' of recurrent pneumonia. These patients frequently have a history of nocturnal coughing (89%), recurrent pneumonias (94%) and a history of vomiting during infancy (42%) [11]. The children most at risk for aspiration pneumonia are also the most severely involved cognitively and have the greatest degree of spasticity [8. 12, 13], Children with a history of reactive airway disease should also be suspect since their reactive airway disease may be due to occult esophageal reflux [10, 11]. Lastly children with an enlarged gastric bubble on the preopera tive X-ray arc also at risk for developing an aspiration pneumonia. At NYUMC 5 of our rhizotomy patients developed aspiration pneumonia postoperatively with 3 of these requiring artificial ventilation with PEEP for at least 18 h after surgery. Two patients had a major lung segment or lobe collapse of unclear etiology during surgery resulting in the abandonment of the surgery and a period of postop erative artificial ventilation with PEEP. Measures used at NYUMC to avoid aspiration pneumonia are obvious. Abdominal x-rays are checked for signs of an enlarged gastric bubble heralding gastric stasis. Children with a his tory of gastric reflux or pneumonia are given a Hi blocker to decrease the acidity of the gastric contents to decrease its harmfulness if aspirated. Since the introduction of Hy blocker use, 180 rhizotomies have been performed with out a seerious case of aspiration pneumonia occurring.
Bowel and Bladder Dysfunction
Urinary Retention Children with cerebral palsy are at risk to develop a symptomatic neurogenic bladder. McNeal ct al. [14] re ported an 8% incidence of neurogenic bladder by cystometrograms and a 36% incidence of symptoms suggesting neurogenic bladder (enuresis, stress incontinence and dribbling) in 50 individuals interviewed at a cerebral palsy center. Postrhizotomy urinary retention may be a result of several factors. A loss of blood supply to the conus secondary to severing of important radicular arter ies may occur during the surgery leading to an infarct within the conus. Contusion of motor roots within the cauda also could explain any bladder dysfunction. Addi
Selective Posterior Rhizotomy
Downloaded by: Stockholm University Library 130.237.165.40 - 2/27/2018 5:05:41 PM
Respiratory Complications
Constipation and Ileus Postoperative gastrointestinal problems include con stipation as well as transient ileus. 3/250 children devel oped a postoperative ileus requiring 48 h of suctioning via a nasogastric tube. 20-25% of the children have trouble moving their bowels after the surgery. These adverse effects may be because of a predisposition to constipation or effects of anesthesia and postoperative narcotics. We are impressed that these children are very susceptible to postoperative constipation/ileus. For that reason we have become very conservative with their dietary advancement postoperatively.
Postoperative Discomfort
Discomfort is a near universal feature of the imme diate postoperative recovery period. Nearly all patients who have the selective rhizotomy procedure experience moderate to severe postoperative pain for the first 4872 h postoperatively. This is frequently accompanied by back spasms and an increase in the individual's baseline muscle tone. Nearly half the patients also will experience dysesthesias in a stocking distribution in the legs. Morphine sulfate 0.15-0.2 mg/kg subcutaneously ev ery 3-4 h is necessary for 24-48 h postoperatively. This is frequently augmented with a benzodiazepam to abort an escalating pain-spasm cycle. The pain dramatically disap pears in the 2nd to 3rd postoperative day allowing the dis continuance of narcotic pain medication. Parental prepa ration for the intensive postoperative pain will reduce their anxiety and allow them to focus their attention on comforting their child. During the immediate postoperative period children in severe discomfort may have persisting spasticity in their legs. Increased spasticity also may be evident during times of increased stress (due to illness, anxiety, etc.) for months and even years following surgery. We have now seen this in 10 of our patients, all of whom were spastic quadriplegics preoperatively. Dysesthesias or ‘needles and pins’ sensations in the legs are also common during the postoperative period. It has been reported as a side effect of sensory rhizotomies used to treat localized pain syndromes [16]. This is the same type of unpleasant sensation that occurs in spinal cord injury, expanding syringes and after surgery for intramedullary spinal cord tumors. It has been theorized that this represents an imbalance between the dorsal col umn fibers and spinothalamic fibers within the affected individual's spinal cord. The theory arose from observing individuals with spinal cord injuries resulting in a loss of pain and temperature sensation but preservation of dor sal column sensation [17]. As the utility of selective sen sory rhizotomy in treating spasticity was discovered serendipitously during its application to treat pain syn dromes. it should not be surprising that the density of pain fibers in those rootlets cut to treat spasticity is greater than those preserved. These dysesthetic sensa tions typically decrease in intensity with time in our patients and usually require no treatment other than patient/parental reassurance. Frequently these dysesthe sias are lessened if the child wears socks while in bed or therapy. On rare occasions carbamazepine has been used to treat the condition.
45
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tionally, since some children’s bladders may be depen dent upon spasmodic evacuation preoperatively, deafferentation could result in a decrease in ability to evacuate. The reduction in spasticity that occurs with the severing of the nerve rootlets would then leave the child with a hypotonic bladder requiring intermittent catheterization on either a temporary or permanent basis. Most impor tantly, we have discovered that there is a variability in the distribution of afferent pudendal nerve fibers within the cauda equina [ 15]. We have found that the afferent fibers of the penile/clitoral cutaneous branch of the pudendal nerve can be confined to a single, unilateral sacral root. Therefore, we postulate that fibers involved in the blad der’s reflex circuits could be isolated to a single root within the target zone of the SPR surgery. Postoperative urinary retention requiring intermittent catheterization has been necessary in 13 of the 250 patients who have undergone the rhizotomy procedure at NYUMC. One patient is still dependent on a catheteriza tion program 18 months after surgery. Children at great est risk for the development of postoperative bladder complications include those with a history suggesting a spastic bladder. This includes those with histories of recurrent urinary tract infections or constipation. De layed toilet training or the incidence of daytime inconti nence are also symptoms suggesting bladder spasticitv [14]. Clinical management of children should include pre operative cystometrograms for those with histories sug gesting spastic bladders. Parents should be warned of the possibility of intermittent catheterization for a period after the surgery and of the remote possibility of perma nent bladder dysfunction. Intraoperatively, we use prelesioning pudendal neurograms to avoid lesioning of root lets with significant pudendal afferent activity [15].
Alteration in Sensation Four of our patients have experienced focal areas of sensory loss postoperatively. Three of these patients have loss proprioception in one of their ten toes and one patient has loss pain and temperature sensation in the right SI dermatome. These deficits remained at their 6month postoperative réévaluation.
Long-Term Complications
We have now been able to follow over 50 patients for more than 2 years post-rhizotomy. We are becoming increasingly aware of several long-term complications that can potentially arise. Of utmost concern is the poten tial for functional decline in these patients. Several au thors have mentioned that the alleviation of spasticity can result in a decline in leg function if the spasticity is being used to help in weight bearing [18-21], This can be avoided by examining the patients’ concentric and eccen tric strength in their antigravity muscles. Using a simple test such as the ability to slowly rise out of a squat to stand and then lower back into a squat will examine a child’s antigravity strength [18]. A demonstrated ability to do this predicts adequate strength to bear the body’s weight standing. Loss in Muscle Range Many children we have been able to follow after their surgery have presented with progressive loss in muscle range of motion. This typically occurs in the hip adduc tors, hamstrings and gastrocnemius muscles. A history of a recent growth spurt is common. Most importantly, all the children who experienced this were not obtaining clasical muscle stretching therapy during the growth spurt. The loss of muscle range typically resulted in a deteriora tion in the child’s gait pattern and. usualy, the range loss could be reversed with an aggressive muscle stretching program. In 8 children, however, tendonotomies were required to regain the loss muscle range. This complica tion underlines the importance of maintenance therapy in these children, particularly during times of rapid growth. This is because muscle contractures persist in the legs' musculature although the spasticity has been treated.
dysplasia who undergo SPR are at a higher risk for pro gressive dislocation when compared to children with nor mal hips who undergo SPR. Six of our patients have now undergone varus derotation osteotomies of the femurs for progressive dislocation of the hips. All these children were crawling before their surgery and after their surgery ad vanced to use walking as their main mode of locomotion. When walking these children exhibited poor control of hip alignment during terminal stance phase due to weak ness in their hip abductors and hip extensors. We now obtain preoperative hip X-rays and place children whom we think are at risk for hip subluxation in orthosis with single lateral upright bracing attached to a pelvic band after their surgery. This is done to support the hip joint during ambulation.
Conclusion
Postoperative complications of the SPR procedure oc cur in a small percentage of the operative cases. At NYUMC we feel that these complications can be mini mized or avoided by identifying those children at risk with detailed history and physical examination. These patients can then receive prophylactic treatment or care ful monitoring for prevention or treatment of such com plications. Additionally, it is vital that the family be aware of those risks for permanent dysfunction and those which cause transient discomfort or dysfunction.
46
Abbott
Selective Posterior Rhizotomy
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Hip Dislocation Progressive dislocation of the hips is possible after SPR. Greene et al. [22] have recently reported rapid sub luxation of the hips in 6 children who had undergone SPR. It was their feeling that children with preexisting hip
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16 White JC. Kjellberg RN : Posterior rhizotomy: A substitute for cordotomy in the relief of local ized pain in patients w ith normal life-expectan cy. Neurochirurgia 1973:16:141-170. 17 Beric A, Dimitrijevic MR. Lindblom U: Cen tral dysesthesia syndrome in spinal cord inujury patients. Pain 1988:34:109-116. 18 Elk B: Pre-operative assessment and post-surgi cal occupational therapy for children who have undergone a selective posterior rhizotomy. S Afr J Occup Thcr 1984:14:45-50. 19 Foerster O: On the indications and results of the excision of posterior spinal roots in men. SurgGyn Obst 1913:16:463-475. 20 Peacock WJ. Stout LA: Functional outcome following selective posterior rhizotomy in chil dren with cerebral palsy. J Neurosurg 1991:74: 380-385. 2 1 Privât JM. Benezcch J. Frerebrau P. Gros C: Sectorial posterior rhizotomy, a new technique o f surgical treatment of spasticity. Acta Neuroehir 1976:35:181-195. 22 Greene WB. Dietz FR. Goldberg MJ. Gross RH, Miller F. Sussman MD: Rapid subluxa tion in cerebal palsy after selective posterior rhizotomy. .1 Pediatr Orthop 1991:11:494497.
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