.

It is not an actual "phase", simply the next step

if you mean "llegará"

In more resistance cases, the surgical phase is called for


Explanation:
In more resistant cases, surgery may be necessary/called for

something to this effect

as in several other suggestions I think 'may' would sound better

There is not enough context, but I am wondering whether they are talking about treatment-resistant cases, i.e. do not respond to medication, so they have to go on to surgical treatment.

Treatment of epilepsy following rejection of epilepsy surgery ...
Kev words: drug resistance; epilepsy surgery; lost hope; phamacotherapy; ... extent of pharmacoresistance which should be reached before considering surgery. .... In the individual case, they may be more successful than firstline drugs. ...
linkinghub.elsevier.com/retrieve/pii/S1059131198900048 - Similar
by P Wolf - 1998 - Cited by 5 - Related articles - All 4 versions


Recent advances in the medical and surgical treatment of multi ...
Recent advances in the medical and surgical treatment of multi-drug resistant tuberculosis. Lalloo UG, Naidoo R, Ambaram A. ...
www.ncbi.nlm.nih.gov/pubmed/16582672 - Similar
by UG Lalloo - 2006 - Cited by 15 - Related articles - All 4 versions

#
Arch Dermatol -- Abstract: Treatment-Resistant Alopecia Areata ...
... Facial Plastic Surgery, Family Medicine (1992-2000), General Psychiatry ... Treatment-Resistant Alopecia Areata. Response to Combination Therapy With ...
archderm.ama-assn.org/cgi/content/abstract/126/6/756 - Similar
by VC Fiedler - 1990 - Cited by 37 - Related articles - All 3 versions
#
Successful treatment of treatment-resistant laser-induced pigment ...
Surgical treatment options for this ... Lasers in Surgery and Medicine 27:358–361 (2000) .... ing of cosmetic tattoos may not be truly resistant ...
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Note added at 5 hrs (2009-07-25 14:43:23 GMT)
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sorry!!

that should read

treatment-resistant

cannot read my own refs!

Not very literal, but I think this is the meaning.