11
Surgical management of spasticity
Patrick Mertens and Marc Sindou
Introduction
Spasticity is one of the commonest sequelae of neu-
rological diseases. In most patients spasticity is use-
ful in compensating for lost motor strength. Never-
theless, in a significant number of patients it may
become excessive and harmful, leading to further
functional losses. When not controllable by phys-
ical therapy, medications and/or botulinum toxin
injections, spasticity can benefit from neurostimula-
tion, intrathecal pharmacotherapy or selective abla-
tive procedures.
Neuro-stimulation procedures
Stimulation of the spinal cord was developed in the
1970s on the basis of the ‘gate-control theory’ of
Melzach and Wall (1974) for the treatment of neu-
rogenic pain. This method has been found to be
partially effective in the treatment of spastic syn-
dromes, such as those encountered in multiple scle-
rosis (Cook & Weinstein, 1973; Gybels & Van Roost,
1987) or spinal cord degenerative diseases, such as
Strumpell–Lorrain syndrome. However, this method
is generallymost effective when spasticityis mildand
the dorsal column has sufficient functional fibres,
as assessed by somatosensory evoked potentials.
Stimulation electrodes are implanted, either per-
cutaneously through a Tuohy needle under X-ray
fluoroscopy or surgically via an open interlaminar
approach in the extradural space posteriorly to the

is reduced without suppression of useful muscular
193
194 Patrick Mertens and Marc Sindou
tone or impairment of the residual motor and sen-
sory functions. Therefore, neuroablative techniques
must be as selective as possible. Such selective
lesions can be performed at the level of peripheral
nerves, spinal roots, spinal cord or the dorsal root
entry zone.
Peripheral neurotomies (PNs)
Selective PNs were introduced first for the treatment
of spastic deformities of the foot by Stoffel (1913).
Later, Gros et al. (1977) and Sindou and Mertens
(1988) advocated making neurotomies more selec-
tive by using microsurgical techniques and intra-
operative electrical stimulation for better identifica-
tion of the function of the fascicles constituting the
nerve. Selectivity is required to suppress the excess
of spasticity without producing excessive weakening
of motor strengthand severe amyotrophy. To achieve
this goal, preserving at least one-fourth of the motor
fibres is necessary.
Neurotomies are indicated when spasticity is
localized to muscles or muscular groups supplied
by a single or a few peripheral nerves that are easily
accessible. To help the surgeon decide if neurotomy
is appropriate, temporary local anaesthetic block of
the nerve (with lidocaine or with long-lasting bupi-
vacaine) can be useful. Such a test can determine if
articular limitations result from spasticity or muscu-

the components of the spastic disorder, according
to the following schedule: (1) equinus and/or ankle
clonus requires sectioning of the soleus nerve(s) and,
if necessary, the two gastrocnemius branches; (2)
varus necessitates interruption of the posterior tib-
ial nerve; and (3) tonic flexion of the toes requires
sectioning of the flexor fascicles situated inside the
distal trunk of the tibial nerve. Their precise identi-
fication, avoiding sensory fascicles, is of paramount
importance in avoiding hypoaesthesia and dysaes-
thetic disturbances as well as trophic lesions of the
plantar skin.
In 180 patients, 82% of tibial PNs resulted in sup-
pression of the disabling spasticity with improve-
ment of the residual voluntary movements (P.
Mertens & M. Sindou, unpublished data). We have
recently published the results of a multicentre study
of the long-term results of tibial neurotomy (Buf-
fenoir et al., 2004). This multicentre, prospective
study was conducted between 1999 and 2003 and
55 patients with spastic equinus foot were treated
in five neurosurgical centres. No postoperative com-
plications were observed in this series. Gait analy-
sis demonstrated a statistically significant increase
in the speed of gait after the surgical treatment and
improvements in the equinus score and foot appear-
ance. Overall 92.7% of preoperative objectives had
been achieved in the series, and there seemed to be
Figure 11.1. Selective tibial neurotomy. Left: Skin incision in the right popliteal fossa. Centre: Dorsal view showing tibial
(1), and peroneal (2) nerves, sural (sensory) nerve (3), medial gastrocnemius and lateral gastrocnemius branches (4), soleus

ski sign), a selective neurotomy of the branch(es) of
the deep fibular nerve to the hallux extensor can be
useful.
Upper limbs
Neurotomies are also indicated for spasticity in the
upper limbs (Mertens & Sindou, 1991). Selective
fascicular neurotomies can be performed in the
musculocutaneous nerve for spastic elbow flexion
(Fig. 11.4), and in the median (and ulnar) nerve
for spastic hyperflexion of the wrist and fingers
(Fig. 11.5).
The last procedure, which consists of sectioning
the branches to the forearm pronators, wrist flexors
and extrinsic finger flexors, is indicated for spasticity
in the wrist and the hand – the aim being to open
the hand and improve prehension. As the fascicular
organization of the median and ulnar nerves does
not allow for differentiation of motor from sensory
fascicles at the level of their trunks, it is necessary
to dissect the motor branches after they have left
the nerve trunk in the forearm. Special care must
be taken with the sensory fascicles to avoid painful
manifestations.
Neurotomies of brachial plexus branches have
now been developed for treating the spastic shoul-
der (Decq et al., 1997). The pectoralis major mus-
cle and teres major muscle are the main muscles
implicated in this condition. This excess of spas-
ticity restrains the active (and passive) abduction
Surgical management of spasticity 197

cles (Fig. 11.6). This was certainly true for 82% of 180
adult patients operated on for spastic foot using tib-
ial PN. In our experience – since 1980 and more than
300 operations – tibial neurotomy has been the most
frequently used PN (Mertens & Sindou, unpublished
data).
With regard to the spastic hand, which is a very
difficult problem to deal with, a functional bene-
fit in prehension can only be achieved if patients
retain a residual motor function in the extensor and
198 Patrick Mertens and Marc Sindou
Figure 11.5. Median neurotomy (slightly modified from
Brunelli’s technique). Top: Skin incision on the right
forearm from the medial aspect of the biceps brachii at the
level of the elbow to the midline above the wrist. Centre:
First stage of the dissection; the pronator teres (PT) is
retracted upward and laterally, and the flexor carpi radialis
(FCR) is retracted medially. Branches from the median
nerve (MN), before it passes under the fibrous arch of the
flexor digitorum superficialis (FDS), are dissected. These
branches are (1) to the pronotor teres and (2,3) two nerve
trunks to the flexor carpi radialis, palmaris longus and
flexor digitorum superficialis. Bottom: Second stage of the
dissection; the fibrous arch of the FDS is sectioned to allow
more distal dissection of the median nerve. The FDS is
retracted medially, and branches from the median nerve
are identified to the (1) flexor pollicis longus (FPL),
supinator muscles together with a sufficient residual
sensory function. If these conditions are not present,
only better comfort and better cosmetic aspect can

one rootlet in five of each root, from L1 to S1.
Using similar principles, Ouaknine (1980), a pupil
of Gros, developed a microsurgical technique that
(2) flexor digitorum profundus (FDP) and (3) the
interosseous nerve and its proper branches to these
muscles.
Surgical management of spasticity 199
(a)
(b)
Figure 11.6 Movement analysis in a hemiplegic patient with a spastic foot (equinovarus) before and after selective tibial
neurotomy. (a) Surface polyelectromyography of the tibialis anterior (LAED) and the triceps surae (LPD) muscles on the
spastic leg during walking. Left: Preoperative recordings showing desynchronized activities of the triceps surae, with
abnormal co-contractions of antagonist muscles – triceps surae and tibialis anterior. Right: After selective tibial neurotomy
there is a reappearance of muscular activities in the tibialis anterior muscle, a clear decrease in triceps surae activities and
normal alternance of contractions of these muscles (i.e. triceps surae at the end of the stance phase and tibialis anterior
during the swing phase). (b) Tridimensional movement analysis of the ankle flexion-extension amplitude during the gait
with VICON system. Left: Preoperatively, the amplitude of the spastic ankle is limited to 18 degrees of dorsal flexion. Right:
After selective tibial neurotomy, the dorsal flexion increased to 32 degrees. Thus, the tonic balance of the ankle has been
re-equilibrated by the selective tibial neurotomy; consequently, motor function and gait have been improved.
consisted of resectioning one third to two thirds of
each group of rootlets of all the posterior roots from
L1 to S1.
Sectorial posterior rhizotomy
In an attempt to reduce the side effects of rhi-
zotomy on postural tone in ambulatory patients,
Gros (1979) and his pupils Privat et al. (1976) and
Frerebeau (1991) proposed a topographic selec-
tion of the rootlets to be sectioned. Firstly, a pre-
operative assessment is done to differentiate the
‘useful spasticity’ (i.e. the one sustaining postu-

ited spinal circuits responsible for spasticity. This
procedure, which was especially conceived for use
with children with cerebral palsy, has been also used
by other outstanding surgical teams, each one hav-
ing brought its own technical modifications to the
method (Peacock & Arens, 1982; Cahan et al., 1987;
Storrs, 1987; Abbott et al., 1989).
Personal technique
Our personal adaptations of these methods are sum-
marized below. Selection of candidates for surgery
was done in a multidisciplinary way, with the reha-
bilitation team, the physiotherapist, the orthopaedic
surgeon and the neurosurgeon being present, as
well as of course the patient’s family. Candidates
were retained only if spasticity was responsible for
a halt in motor skill acquisitions and/or evolutive
orthopaedic deformities in spite of intensive phys-
iotherapy. The main goals of the surgery were clearly
defined for every patient: improvement in comfort;
decrease in orthopaedic risks; improvement for sit-
ting, standing and/or walking; and improvement
in urinary function. The muscles in which there
was a harmful excess of tone and their – anatom-
ically – corresponding lumbosacral roots (i.e. those
to be resected, as well as the degree of their resec-
tioning according to amount of spasticity to be
reduced) were determined by the multidisciplinary
team. The surgical procedure used is detailed in Fig-
ure 11.7. Until recently, we have operated only on
very severely affected children – quadriplegic and

position
11–
Improvement
of standing
and walking
862
Improvement
of vesical
function
101
Total 18 10 8